Plumbing sizing calculations for a house

Last updated October 22, 2026

When this shows up on the exam

The Plumbing House exam asks you to total fixture units for a house, pick a drain, stack or branch size from a table at a given slope, check a trap arm length, size a vent, convert roof area into a storm load and size a water pipe. The On-site Sewage Systems exam asks the simpler versions: fixture unit totals, fixture outlet sizes and the minimum slope of small drains.

The method

List every fixture draining to the pipe you are sizing. The load on a pipe is everything upstream of it, including fixtures roughed in for the future and any roof or paved area that drains into it (OBC Div. B 7.4.10.1.).
Give each fixture its drainage load from Table 7.4.9.3. A fixture that is not listed takes its load from its trap size in Table 7.4.10.2. (OBC Div. B 7.4.10.2.). Watch the rows that depend on trap size.
Use the bathroom group value when a water closet, a domestic lavatory and one bathtub or one single-head shower share a room. A flush-tank bathroom group is 6 fixture units, not the sum of its parts.
Add continuous flows. A pump or air-conditioning fixture adds 31.7 fixture units per L/s of flow to a sanitary system (OBC Div. B 7.4.10.3.).
Pick the table that matches the pipe: stack, Table 7.4.10.6.-A (check both the total and the per-storey column); branch, Table 7.4.10.6.-B; sanitary building drain or sewer, Table 7.4.10.6.-C in the column for the actual slope. Choose the smallest size whose limit is at least your load.
Apply the minimum sizes that override the tables: NPS 3 for any pipe serving a water closet, NPS 4 downstream of the third water closet (OBC Div. B 7.4.9.2.) and NPS 4 for a building drain or sewer downstream of the main cleanout when connected to a public sewer (OBC Div. B 7.4.9.4.).
Check the slope. Drainage pipes of NPS 3 or less need at least 1 in 50 (OBC Div. B 7.4.8.1.). Fall equals run divided by the slope ratio.
Trap arms and vents. Read the maximum trap arm length for the trap size in Table 7.5.6.3. An individual or dual vent is sized from the largest trap served using Table 7.5.7.1., with no length check (OBC Div. B 7.5.8.2.). A branch vent, header, circuit or continuous vent uses load and developed length in Table 7.5.8.3. A wet vent uses Table 7.5.8.1., leaving out the most downstream fixture.
Storm loads. Load in litres = SB-1 15 min rainfall (mm) x (horizontal roof area + one-half of the largest adjoining wall area) in m² (OBC Div. B 7.4.10.4.). The rainfall is the "15 Min Rain, mm" column of SB-1 Table 2. Size leaders with Table 7.4.10.11. and storm drains with Table 7.4.10.9. For a combined sewer, sanitary fixture units convert to litres: 2,360 L for 260 fixture units or fewer (OBC Div. B 7.4.10.5.).
Water pipes. Total the private use supply loads from Table 7.6.3.2.-A, then, for a house meeting the conditions in OBC Div. B 7.6.3.4.(5), read the smallest size in Table 7.6.3.4. under the chosen velocity column.

Worked example 1: total load and building drain size

A house has two bathroom groups with flush tanks, a powder room (flush-tank water closet and a domestic lavatory with an NPS 1¼ trap), a kitchen sink, a domestic dishwasher with its own drain connection, a clothes washer draining to a standpipe, and a floor drain with an NPS 2 trap. The building drain runs at 1 in 50 to a municipal sewer.

Fixture	Fixture units
2 bathroom groups x 6	12
Water closet, flush tank	4
Lavatory, NPS 1¼ trap	1
Kitchen sink	1½
Dishwasher (separate connection)	1
Clothes washer, domestic	1½
Floor drain, NPS 2 trap	2
Total	23

Table lookup: Table 7.4.10.6.-C, row NPS 3, column "1 in 50" gives 27 fixture units, so by load alone NPS 3 would work. But there are three water closets, so the drain downstream of the third one must be at least NPS 4 (OBC Div. B 7.4.9.2.(2)), and the drain downstream of the main cleanout must be NPS 4 anyway (OBC Div. B 7.4.9.4.(1)). NPS 4 at 1 in 50 allows 240. Answer: NPS 4. Note that 7.4.8.1. sets 1 in 50 only for NPS 3 or less; an NPS 4 drain could run at 1 in 100 (limit 180).

Worked example 2: trap arm length and fall

A kitchen sink has an NPS 1½ trap. Table 7.5.6.3., row NPS 1½, gives a maximum trap arm of 1.8 m at a minimum slope of 1 in 50 (OBC Div. B 7.5.6.3.(4)). Fall at full length: 1,800 mm / 50 = 36 mm. Article 7.5.6.3. also limits the total fall of the trap arm to its inside diameter and the cumulative change in direction to 135°. Check the inside diameter of the actual pipe used.

Worked example 3: vent sizes

The kitchen sink in Example 2 gets an individual vent. Table 7.5.7.1., row "NPS 1½" trap, gives a minimum NPS 1¼ vent, and length is not considered.

Upstairs, a branch vent serves two flush-tank bathroom groups (12 fixture units) and has a developed length of 12 m. Table 7.5.8.3. has rows for 8 and 20 fixture units and does not say how to treat a load in between, so the safe reading is the row at or above your load: row 20. NPS 1¼ is limited to 7.5 m (too short); NPS 1½ allows 15 m. Answer: NPS 1½. (Here the 8 row gives the same size, since NPS 1¼ allows only 9 m there.) Separately, every sanitary building drain needs at least one vent of NPS 3 or more (OBC Div. B 7.5.7.2.(2)).

Worked example 4: roof storm load

A house in Toronto (City Hall location) has a roof with a horizontal projection of 120 m², and a 30 m² wall drains onto it. SB-1 Table 2 gives a 15 min rain of 25 mm.

Effective area: 120 + (30 / 2) = 135 m²
Load: 135 x 25 = 3,375 L
Circular leader, Table 7.4.10.11.: NPS 2½ carries 3,070 L (too small), NPS 3 carries 5,000 L. Leader: NPS 3.
Storm building drain at 1 in 100, Table 7.4.10.9.: NPS 4 carries 4,220 L, which also meets the NPS 4 minimum for storm drains (OBC Div. B 7.4.9.4.(2)).

Common mistakes

Adding the water closet, lavatory and tub separately (6½) instead of using the bathroom group value (6).
Counting a domestic dishwasher that drains through the kitchen sink.
Using the wrong trap-size row for a lavatory or floor drain.
Using the "2 or 3 heads" shower row for a 4-head shower.
Checking only the stack total and forgetting the "from any 1 Storey" limit in Table 7.4.10.6.-A.
Reading Table 7.4.10.6.-C in the wrong slope column, or forgetting the NPS 4 minimums.
Applying the NPS 1½ trap arm row to an NPS 2 trap, or using the 1 in 100 row (NPS 4 only).
Using the row below your load in Table 7.5.8.3., which can give an undersized vent.
Including the most downstream fixture when sizing a wet vent.
Taking the whole wall area instead of half, or using the one-day rain column.
Applying the 75% hot and cold reduction when 7.6.3.4.(5) requires 100% of the load.

Find it fast in the code PDF

Bookmark Division B > Part 7 > Section 7.4 for drainage and Section 7.5 for venting. Useful Ctrl+F phrases:

"Minimum Permitted Size of Fixture Outlet Pipe" (fixture unit table)
"downward slope in the direction of flow" (7.4.8.1.)
"Maximum Permitted Hydraulic Load Drained to a Stack"
"largest adjoining vertical surface" (roof loads)
"Length of Trap Arm"
"Maximum Length of Vent Pipe"
"most downstream fixture" (wet vents)
"Sizing of Water Distribution Systems" (Section 7.6)
"15 Min Rain" (SB-1, Table 2)

Drill these questions

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Code cited in this method

Based on the official 2024 Building Code Compendium on ontario.ca.

OBC Div. B 7.4.10.1. Total Load on a Pipe
(1)The hydraulic load on a pipe is the total load from
(a)every fixture that is connected to the system upstream of the pipe,
(b)every fixture for which provision is made for future connection upstream of the pipe, and
(c)all roofs and paved surfaces that drain into the system upstream of the pipe.
Open OBC Div. B 7.4.10.1. in the code viewer
OBC Div. B Table 7.4.9.3. Minimum Permitted Size of Fixture Outlet Pipe and Hydraulic Loads for Fixtures[1]
Table 7.4.9.3. — Minimum Permitted Size of Fixture Outlet Pipe and Hydraulic Loads for Fixtures[1] Forming Part of Sentences 7.4.9.3.(1) and 7.4.10.2.(1) Fixture | Minimum Nominal Pipe Size of Fixture Outlet Pipe, NPS | Hydraulic Load, fixture units Autopsy table | 1½ | 2 Bathroom group (a) with flush tank | N/A | 6 Bathroom group (b) with direct flush valve | N/A | 8 Bathtub (with or without shower) | 1½ | 1½ Bath: foot, sitz or slab | 1½ | 1½ Beer cabinet | 1½ | 1½ Bidet | 1¼ | 1 Chinese range | 1½ | 3 Clothes washer (a) domestic[1] | N/A | 1½ with NPS 2 trap Clothes washer (b) commercial | N/A | 2 with NPS 2 trap Cup sinks | 1¼ | ½ Dental unit or cuspidor | 1¼ | 1 Dishwasher (a) domestic type | 1½ | 1 (no load when connected to garbage grinder or domestic sink) Dishwasher (b) commercial type | 2 | 3 Drinking fountain | 1¼ | ½ Fish tank or tray | 1½ | 1½ Floor drain[2] | 2 | 2 with NPS 2 trap 3 with NPS 3 trap Garbage grinder, commercial type | 2 | 3 Icebox | 1¼ | 1 Laundry tray (a) single or double units or 2 single units with common trap | 1½ | 1½ Laundry tray (b) compartments | 1½ | 2 Lavatory (a) barber or beauty parlor | 1½ | 1½ Lavatory (b) dental | 1¼ | 1 Lavatory (c) domestic type single, or 2 single with common trap | 1¼ | 1 with NPS 1¼ trap 1½ with NPS 1½ trap Lavatory (d) multiple or industrial type | 1½ | According to Table 7.4.10.2. Macerating toilet system | ¾ | 4 Potato peeler | 2 | 3 Shower drain Total volume of discharge from all shower heads and body sprays: (a) from 1 head | 1½ | 1½ Shower drain Total volume of discharge from all shower heads and body sprays: (b) from 2 or 3 heads | 2 | 3 Shower drain Total volume of discharge from all shower heads and body sprays: (c) from 4 to 6 heads | 3 | 6 Sink (a) domestic and other small types with or without garbage grinders, single, double or 2 single with a common trap | 1½ | 1½ Sink (b) other sinks | 1½ | 1½ with NPS 1½ trap 2 with NPS 2 trap 3 with NPS 3 trap Urinal (a) pedestal, siphon jet or blowout type | 2 | 4 Urinal (b) stall, washout type | 2 | 2 Urinal (c) wall (i) washout type | 1½ | 1½ Urinal (c) wall (ii) other types | 2 | 3 Water closet (a) with flush tank | 3 | 4 Water closet (b) with direct flush valve | 3 | 6 Notes to Table 7.4.9.3.: (1) See Note A-Table 7.4.9.3. (2) No hydraulic load for emergency floor drains.
Open OBC Div. B Table 7.4.9.3. in the code viewer
OBC Div. B Table 7.4.10.2. Permitted Hydraulic Load from a Fixture Based on Size of Trap
Table 7.4.10.2. — Permitted Hydraulic Load from a Fixture Based on Size of Trap Forming Part of Sentence 7.4.10.2.(2) Nominal Pipe Size, NPS | Hydraulic Load fixture units 1¼ | 1 1½ | 2 2 | 3 2½ | 4 3 | 5 4 | 6
Open OBC Div. B Table 7.4.10.2. in the code viewer
OBC Div. B 7.4.10.2. Hydraulic Loads for Fixtures
(1)The hydraulic load from a fixture that is listed in Table 7.4.9.3. is the number of fixture units set forth in the Table.
(2)Except as provided in Sentence (1), the hydraulic load from a fixture that is not listed in Table 7.4.9.3. is the number of fixture units set forth in Table 7.4.10.2. for the nominal pipe size of the trap that serves the fixture.
Open OBC Div. B 7.4.10.2. in the code viewer
OBC Div. B 7.4.10.3. Hydraulic Loads from Fixtures with a Continuous Flow
(1)Except as provided in Sentence (2), the hydraulic load from a fixture that produces a continuous flow, such as a pump or an air-conditioning fixture, is 31.7 fixture units for each litre per second of flow.
(2)Where a fixture or equipment that produces a continuous or semi-continuous flow drains to a combined sewer or to a storm sewer, the hydraulic load from the fixture is 900 L for each litre per second of flow.
Open OBC Div. B 7.4.10.3. in the code viewer
OBC Div. B Table 7.4.10.6-A. Maximum Permitted Hydraulic Load Drained to a Stack
Table 7.4.10.6.-A Maximum Permitted Hydraulic Load Drained to a Stack Forming Part of Sentences 7.4.10.6.(1) and 7.5.7.3.(2) and Table 7.5.8.4. Nominal Pipe Size of Stack, NPS | Maximum Hydraulic Load, fixture units | Maximum Fixture Units Drained from any 1 Storey 1¼ | 2 | 2 1½ | 8 | 2 2 | 24 | 6 3 | 102 | 18 4 | 540 | 100 5 | 1,400 | 250 6 | 2,900 | 500 8 | 7,600 | 830 10 | 15,000 | 2,700 12 | 26,000 | 4,680 15 | 50,000 | 9,000
Open OBC Div. B Table 7.4.10.6-A. in the code viewer
OBC Div. B Table 7.4.10.6-B. Maximum Permitted Hydraulic Load Drained to a Branch
Table 7.4.10.6.-B — Maximum Permitted Hydraulic Load Drained to a Branch Forming Part of Sentences 7.4.10.6.(2), 7.4.10.7.(1) and 7.5.7.3.(2) Nominal Pipe Size of Branch, NPS | Maximum Hydraulic Load, fixture units 1¼ | 2 1½ | 3 2 | 6 3 | 27 4 | 180 5 | 390 6 | 700 8 | 1,600 10 | 2,500 12 | 3,900
Open OBC Div. B Table 7.4.10.6-B. in the code viewer
OBC Div. B Table 7.4.10.6-C. Maximum Hydraulic Load, fixture units[2]
Table 7.4.10.6.-C[1] — Maximum Hydraulic Load, fixture units[2] Forming Part of Sentence 7.4.10.6.(2) and Article 7.4.10.8. Nominal Pipe Size of Drain or Sewer, NPS | Slope: 1 in 400 | Slope: 1 in 200 | Slope: 1 in 133 | Slope: 1 in 100 | Slope: 1 in 50 | Slope: 1 in 25 3 | N/A | N/A | N/A | N/A | 27 | 36 4 | N/A | N/A | N/A | 180 | 240 | 300 5 | N/A | N/A | 380 | 390 | 480 | 670 6 | N/A | N/A | 600 | 700 | 840 | 1,300 8 | N/A | 1,400 | 1,500 | 1,600 | 2,250 | 3,370 10 | N/A | 2,500 | 2,700 | 3,000 | 4,500 | 6,500 12 | 2,240 | 3,900 | 4,500 | 5,400 | 8,300 | 13,000 15 | 4,800 | 7,000 | 9,300 | 10,400 | 16,300 | 22,500 Notes to Table 7.4.10.6.-C: (1) See Note A-Table 7.4.10.6.-C. (2) Slope is the ratio of rise to run, in whatever measurement units are chosen.
Open OBC Div. B Table 7.4.10.6-C. in the code viewer

Show all 23 articles

OBC Div. B 7.4.9.2. Serving Water Closets
(1)Drainage pipes that serve a water closet shall be not less than NPS 3.
(2)Branch and building drains downstream of the third water-closet fixture drain connection shall be not less than NPS 4.
(3)Stacks that serve more than 6 water closets shall be not less than NPS 4.
(4)Discharge pipes serving a macerating toilet system shall be not less than NPS 3/4 .
(5)No vertical leg of the drainage pipe from a water closet or other fixture that has an integral siphonic flushing action shall exceed 1,000 mm.
Open OBC Div. B 7.4.9.2. in the code viewer
OBC Div. B 7.4.9.4. Minimum Size of Building Drain and Sewer
(1)Building drains and building sewers connected to the public sewer system downstream of the main cleanout (see Sentence 7.4.7.1.(6)) shall be not less than NPS 4.
(2)Storm building drains and storm building sewers shall be not less than NPS 4.
Open OBC Div. B 7.4.9.4. in the code viewer
OBC Div. B 7.4.8.1. Minimum Slope
(1)Except as provided in Sentences (2) and (3) and Articles 7.4.10.8. and 7.4.10.9., drainage pipes that are NPS 3 or less shall have a downward slope in the direction of flow of at least 1 in 50. (See Note A-7.4.8.1.(1))
(2)Sentence (1) does not apply to a force main.
(3)Where it is not possible to comply with Sentence (1), a lesser slope may be used if it will produce a gravity flow of not less than 0.6 m per second.
Open OBC Div. B 7.4.8.1. in the code viewer
OBC Div. B Table 7.5.6.3. Length of Trap Arm
Table 7.5.6.3. Length of Trap Arm Forming Part of Sentence 7.5.6.3.(4) Nominal Pipe Size of Trap Served, NPS | Maximum Length of Trap Arm, m | Minimum Slope 1¼ | 1.5 | 1 in 50 1½ | 1.8 | 1 in 50 2 | 2.4 | 1 in 50 3 | 3.6 | 1 in 50 4 | 4.9 | 1 in 50 4 | 9.8 | 1 in 100
Open OBC Div. B Table 7.5.6.3. in the code viewer
OBC Div. B Table 7.5.7.1. Minimum Permitted Size of Vent Pipe Based on Size of Trap Served
Table 7.5.7.1. — Minimum Permitted Size of Vent Pipe Based on Size of Trap Served Forming Part of Sentences 7.5.7.1.(1) and 7.5.8.2.(1) Nominal Pipe Size of Trap Served, NPS | Minimum Nominal Pipe Size of Vent Pipe, NPS 1¼ | 1¼ 1½ | 1¼ 2 | 1½ 3 | 1½ 4 | 1½ 5 | 2 6 | 2
Open OBC Div. B Table 7.5.7.1. in the code viewer
OBC Div. B 7.5.8.2. Individual Vents and Dual Vents
(1)The nominal pipe size of individual vents and dual vents shall be determined using Table 7.5.7.1. based on the largest trap served.
(2)When sizing an individual vent or a dual vent, the length is not taken into consideration.
Open OBC Div. B 7.5.8.2. in the code viewer
OBC Div. B Table 7.5.8.3. Maximum Length of Vent Pipe, m[1]
Table 7.5.8.3. — Maximum Length of Vent Pipe, m[1] Forming Part of Article 7.5.8.3. Total Hydraulic Load Served by Vent Pipe, fixture units | Nominal Pipe Size of Vent Pipe, NPS: 1¼ | Nominal Pipe Size of Vent Pipe, NPS: 1½ | Nominal Pipe Size of Vent Pipe, NPS: 2 | Nominal Pipe Size of Vent Pipe, NPS: 3 | Nominal Pipe Size of Vent Pipe, NPS: 4 | Nominal Pipe Size of Vent Pipe, NPS: 5 | Nominal Pipe Size of Vent Pipe, NPS: 6 | Nominal Pipe Size of Vent Pipe, NPS: 8 2 | 9 | NL | NL | NL | NL | NL | NL | NL 8 | 9 | 30 | 61 | NL | NL | NL | NL | NL 20 | 7.5 | 15 | 46 | NL | NL | NL | NL | NL 24 | 4.5 | 9 | 30 | NL | NL | NL | NL | NL 42 | NP | 9 | 30 | NL | NL | NL | NL | NL 60 | NP | 4.5 | 15 | 120 | NL | NL | NL | NL 100 | NP | NP | 11 | 79 | 305 | NL | NL | NL 200 | NP | NP | 9 | 76 | 275 | NL | NL | NL 500 | NP | NP | 6 | 55 | 215 | NL | NL | NL 1,100 | NP | NP | NP | 15 | 61 | 215 | NL | NL 1,900 | NP | NP | NP | 6 | 21 | 61 | 215 | NL 2,200 | NP | NP | NP | NP | 9 | 27 | 105 | 335 3,600 | NP | NP | NP | NP | 7.5 | 18 | 76 | 245 5,600 | NP | NP | NP | NP | NP | 7.5 | 18 | 76 Notes to Table 7.5.8.3.: (1) NP = not permitted and NL = not limited
Open OBC Div. B Table 7.5.8.3. in the code viewer
OBC Div. B Table 7.5.8.1. Maximum Hydraulic Load, Fixture Units
Table 7.5.8.1. — Maximum Hydraulic Load, Fixture Units Forming Part of Sentences 7.5.7.3.(2) and 7.5.8.1.(1) Nominal Pipe Size of Wet Vent, NPS | Not Serving Water Closets | Fixtures, Other Than Water Closets, That Serve Not More Than 2 Water Closets 1½ | 2 | N/A 2 | 4 | 3 3 | 12 | 8 4 | 36 | 14 5 | N/A | 18 6 | N/A | 23
Open OBC Div. B Table 7.5.8.1. in the code viewer
OBC Div. B 7.4.10.4. Hydraulic Loads from Roofs or Paved Surfaces
(1)Except as provided in Sentence (2), the hydraulic load in litres from a roof or paved surface is the maximum 15 min rainfall determined in conformance with MMAH Supplementary Standard SB-1, "Climatic and Seismic Data," multiplied by the sum of
(a)the area in square metres of the horizontal projection of the surface drained, and
(b)one-half the area in square metres of the largest adjoining vertical surface.
(2)Flow control roof drains may be installed, provided
(a)the maximum drain down time does not exceed 24 h,
(b)the roof structure is designed to carry the load of the stored water,
(c)one or more scuppers are installed not more than 30 m apart along the perimeter of the building so that
(i)up to 200% of the 15-minute rainfall intensity can be handled, and
(ii)the maximum depth of controlled water is limited to 150 mm,
(d)they are located not more than 15 m from the edge of the roof and not more than 30 m from adjacent drains, and
(e)there is at least one drain for each 900 m².
(3)Reserved.
(4)Where the height of the parapet is more than 150 mm or exceeds the height of the adjacent wall flashing,
(a)emergency roof overflows or scuppers described in Clause (2)(c) shall be provided, and
(b)there shall be a minimum of 2 roof drains.
Open OBC Div. B 7.4.10.4. in the code viewer
OBC SB-1 Table 2: Climatic Design Data
Table 2: Climatic Design Data
Location | Elevation, m | Design Temperature — January — 2.5%, °C | Design Temperature — January — 1%, °C | Design Temperature — July 2.5% — Dry, °C | Design Temperature — July 2.5% — Wet, °C | Degree Days Below 18°C | 15 Min Rain, mm | One Day Rain, 1/50, mm | Annual Rain, mm | Moisture Index | Annual Total Precipitation, mm | Driving Rain Wind Pressures, Pa, 1/5 | Snow Load, kPa, 1/50 — Ss | Snow Load, kPa, 1/50 — Sr | Hourly Wind Pressures, kPa — 1/10 | Hourly Wind Pressures, kPa — 1/50
Ailsa Craig | 230 | -17 | -19 | 30 | 23 | 3840 | 25 | 103 | 800 | 0.9 | 950 | 180 | 2.2 | 0.4 | 0.37 | 0.48
Ajax | 95 | -20 | -22 | 30 | 23 | 3820 | 23 | 92 | 760 | 0.9 | 825 | 160 | 1.0 | 0.4 | 0.37 | 0.48
Alexandria | 80 | -24 | -26 | 30 | 23 | 4600 | 25 | 103 | 800 | 0.9 | 975 | 160 | 2.4 | 0.4 | 0.31 | 0.4
Alliston | 220 | -23 | -25 | 29 | 23 | 4200 | 28 | 113 | 690 | 0.8 | 875 | 120 | 2.0 | 0.4 | 0.28 | 0.36
Almonte | 120 | -26 | -28 | 30 | 23 | 4620 | 25 | 97 | 730 | 0.8 | 800 | 140 | 2.5 | 0.4 | 0.32 | 0.41
Armstrong | 340 | -37 | -40 | 28 | 21 | 6500 | 23 | 97 | 525 | 0.8 | 725 | 100 | 2.7 | 0.4 | 0.22 | 0.3
Arnprior | 85 | -27 | -29 | 30 | 23 | 4680 | 23 | 86 | 630 | 0.8 | 775 | 140 | 2.5 | 0.4 | 0.29 | 0.37
Atikokan | 400 | -33 | -35 | 29 | 22 | 5750 | 25 | 103 | 570 | 0.8 | 760 | 100 | 2.4 | 0.3 | 0.22 | 0.3
Attawapiskat | 10 | -37 | -39 | 28 | 21 | 7100 | 18 | 81 | 450 | 0.8 | 650 | 160 | 2.8 | 0.3 | 0.3 | 0.41
Aurora | 270 | -21 | -23 | 30 | 23 | 4210 | 28 | 108 | 700 | 0.8 | 800 | 140 | 2.0 | 0.4 | 0.34 | 0.44
Bancroft | 365 | -28 | -31 | 29 | 23 | 4740 | 25 | 92 | 720 | 0.9 | 900 | 100 | 3.1 | 0.4 | 0.25 | 0.32
Barrie | 245 | -24 | -26 | 29 | 23 | 4380 | 28 | 97 | 700 | 0.8 | 900 | 120 | 2.5 | 0.4 | 0.28 | 0.36
Barriefield | 100 | -22 | -24 | 28 | 23 | 3990 | 23 | 108 | 780 | 1.0 | 950 | 160 | 2.1 | 0.4 | 0.37 | 0.47
Beaverton | 240 | -24 | -26 | 30 | 23 | 4300 | 25 | 108 | 720 | 0.9 | 950 | 120 | 2.2 | 0.4 | 0.28 | 0.36
Belleville | 90 | -22 | -24 | 29 | 23 | 3910 | 23 | 97 | 760 | 0.9 | 850 | 180 | 1.7 | 0.4 | 0.34 | 0.43
Belmont | 260 | -17 | -19 | 30 | 24 | 3840 | 25 | 97 | 850 | 1.0 | 950 | 180 | 1.7 | 0.4 | 0.37 | 0.47
Big Trout Lake (Kitchenuhmaykoosib) | 215 | -38 | -40 | 26 | 20 | 7450 | 18 | 92 | 400 | 0.75 | 600 | 150 | 3.2 | 0.2 | 0.31 | 0.42
Borden (CBF) | 225 | -23 | -25 | 29 | 23 | 4300 | 28 | 103 | 690 | 0.82 | 875 | 120 | 2.2 | 0.4 | 0.28 | 0.36
Bracebridge | 310 | -26 | -28 | 29 | 23 | 4800 | 25 | 103 | 830 | 1.0 | 1050 | 120 | 3.1 | 0.4 | 0.27 | 0.35
Bradford | 240 | -23 | -25 | 30 | 23 | 4280 | 28 | 108 | 680 | 0.8 | 800 | 120 | 2.1 | 0.4 | 0.28 | 0.36
Brampton | 215 | -19 | -21 | 30 | 23 | 4100 | 28 | 119 | 720 | 0.8 | 820 | 140 | 1.3 | 0.4 | 0.34 | 0.44
Brantford | 205 | -18 | -20 | 30 | 23 | 3900 | 23 | 103 | 780 | 0.9 | 850 | 160 | 1.3 | 0.4 | 0.33 | 0.42
Brighton | 95 | -21 | -23 | 29 | 23 | 4000 | 23 | 94 | 760 | 0.9 | 850 | 160 | 1.6 | 0.4 | 0.37 | 0.48
Brockville | 85 | -23 | -25 | 29 | 23 | 4060 | 25 | 103 | 770 | 0.9 | 975 | 180 | 2.2 | 0.4 | 0.34 | 0.44
Burk's Falls | 305 | -26 | -28 | 29 | 22 | 5020 | 25 | 97 | 810 | 0.9 | 1010 | 120 | 2.7 | 0.4 | 0.27 | 0.35
Burlington | 80 | -17 | -19 | 31 | 23 | 3740 | 23 | 103 | 770 | 0.9 | 850 | 160 | 1.1 | 0.4 | 0.36 | 0.46
Caledon | 425 | -21 | -23 | 30 | 23 | 4450 | 28 | 119 | 730 | 0.84 | 875 | 140 | 2.2 | 0.4 | 0.31 | 0.4
Cambridge | 295 | -18 | -20 | 29 | 23 | 4100 | 25 | 113 | 800 | 0.9 | 890 | 160 | 1.6 | 0.4 | 0.28 | 0.36
Campbellford | 150 | -23 | -26 | 30 | 23 | 4280 | 25 | 97 | 730 | 0.9 | 850 | 160 | 1.7 | 0.4 | 0.32 | 0.41
Cannington | 255 | -24 | -26 | 30 | 23 | 4310 | 25 | 108 | 740 | 0.9 | 950 | 120 | 2.2 | 0.4 | 0.28 | 0.36
Carleton Place | 135 | -25 | -27 | 30 | 23 | 4600 | 25 | 97 | 730 | 0.8 | 850 | 160 | 2.5 | 0.4 | 0.32 | 0.41
Cavan | 200 | -23 | -25 | 30 | 23 | 4400 | 25 | 97 | 740 | 0.9 | 850 | 140 | 2.0 | 0.4 | 0.34 | 0.44
Centralia | 260 | -17 | -19 | 30 | 23 | 3800 | 25 | 103 | 820 | 1.0 | 1000 | 180 | 2.3 | 0.4 | 0.37 | 0.48
Chapleau | 425 | -35 | -38 | 27 | 21 | 5900 | 20 | 97 | 530 | 0.7 | 850 | 80 | 3.6 | 0.4 | 0.23 | 0.3
Chatham | 180 | -16 | -18 | 31 | 24 | 3470 | 28 | 103 | 800 | 0.9 | 850 | 180 | 1.0 | 0.4 | 0.34 | 0.43
Chesley | 275 | -19 | -21 | 29 | 22 | 4320 | 28 | 103 | 810 | 0.9 | 1125 | 140 | 2.8 | 0.4 | 0.35 | 0.45
Clinton | 280 | -17 | -19 | 29 | 23 | 4150 | 25 | 103 | 810 | 0.9 | 1000 | 160 | 2.6 | 0.4 | 0.36 | 0.46
Coboconk | 270 | -25 | -27 | 30 | 23 | 4500 | 25 | 108 | 740 | 0.9 | 950 | 120 | 2.5 | 0.4 | 0.27 | 0.35
Cobourg | 90 | -21 | -23 | 29 | 23 | 3980 | 23 | 94 | 760 | 0.9 | 825 | 160 | 1.2 | 0.4 | 0.38 | 0.49
Cochrane | 245 | -34 | -36 | 29 | 21 | 6200 | 20 | 92 | 575 | 0.8 | 875 | 80 | 2.8 | 0.3 | 0.27 | 0.35
Colborne | 105 | -21 | -23 | 29 | 23 | 3980 | 23 | 94 | 760 | 0.9 | 850 | 160 | 1.6 | 0.4 | 0.38 | 0.49
Collingwood | 190 | -21 | -23 | 29 | 23 | 4180 | 28 | 97 | 720 | 0.9 | 950 | 160 | 2.7 | 0.4 | 0.3 | 0.39
Cornwall | 35 | -23 | -25 | 30 | 23 | 4250 | 25 | 103 | 780 | 0.9 | 960 | 180 | 2.2 | 0.4 | 0.32 | 0.41
Corunna | 185 | -16 | -18 | 31 | 24 | 3600 | 25 | 100 | 760 | 0.9 | 800 | 180 | 1.0 | 0.4 | 0.37 | 0.47
Deep River | 145 | -29 | -32 | 30 | 22 | 4900 | 23 | 92 | 650 | 0.8 | 850 | 100 | 2.5 | 0.4 | 0.27 | 0.35
Deseronto | 85 | -22 | -24 | 29 | 23 | 4070 | 23 | 92 | 760 | 0.9 | 900 | 160 | 1.9 | 0.4 | 0.34 | 0.43
Dorchester | 260 | -18 | -20 | 30 | 24 | 3900 | 28 | 103 | 850 | 1.0 | 950 | 180 | 1.9 | 0.4 | 0.37 | 0.47
Dorion | 200 | -33 | -35 | 28 | 21 | 5950 | 20 | 103 | 550 | 0.8 | 725 | 160 | 2.8 | 0.4 | 0.29 | 0.39
Dresden | 185 | -16 | -18 | 31 | 24 | 3750 | 28 | 97 | 760 | 0.8 | 820 | 180 | 1.0 | 0.4 | 0.34 | 0.43
Dryden | 370 | -34 | -36 | 28 | 22 | 5850 | 25 | 97 | 550 | 0.7 | 700 | 120 | 2.4 | 0.3 | 0.22 | 0.3
Dundalk | 525 | -22 | -24 | 29 | 22 | 4700 | 28 | 108 | 750 | 0.9 | 1080 | 150 | 3.2 | 0.4 | 0.33 | 0.42
Dunnville | 175 | -15 | -17 | 30 | 24 | 3660 | 23 | 108 | 830 | 1.0 | 950 | 160 | 2.0 | 0.4 | 0.36 | 0.46
Durham | 340 | -20 | -22 | 29 | 22 | 4340 | 28 | 103 | 815 | 0.9 | 1025 | 140 | 2.8 | 0.4 | 0.34 | 0.44
Dutton | 225 | -16 | -18 | 31 | 24 | 3700 | 28 | 92 | 850 | 1.0 | 925 | 180 | 1.3 | 0.4 | 0.37 | 0.47
Earlton | 245 | -33 | -36 | 29 | 22 | 5730 | 23 | 92 | 560 | 0.8 | 820 | 120 | 3.1 | 0.4 | 0.35 | 0.45
Edison | 365 | -34 | -36 | 28 | 22 | 5740 | 25 | 108 | 510 | 0.7 | 680 | 120 | 2.4 | 0.3 | 0.23 | 0.31
Elliot Lake | 380 | -26 | -28 | 29 | 21 | 4950 | 23 | 108 | 630 | 0.8 | 950 | 160 | 2.9 | 0.4 | 0.3 | 0.38
Elmvale | 220 | -24 | -26 | 29 | 23 | 4200 | 28 | 97 | 720 | 0.9 | 950 | 140 | 2.6 | 0.4 | 0.28 | 0.36
Embro | 310 | -19 | -21 | 30 | 23 | 3950 | 28 | 113 | 830 | 0.9 | 950 | 160 | 2.0 | 0.4 | 0.37 | 0.48
Englehart | 205 | -33 | -36 | 29 | 22 | 5800 | 23 | 92 | 600 | 0.8 | 880 | 100 | 2.8 | 0.4 | 0.32 | 0.41
Espanola | 220 | -25 | -27 | 29 | 21 | 4920 | 23 | 108 | 650 | 0.8 | 840 | 160 | 2.3 | 0.4 | 0.33 | 0.42
Exeter | 265 | -17 | -19 | 30 | 23 | 3900 | 25 | 113 | 810 | 0.9 | 975 | 180 | 2.4 | 0.4 | 0.37 | 0.48
Fenelon Falls | 260 | -25 | -27 | 30 | 23 | 4440 | 25 | 108 | 730 | 0.9 | 950 | 120 | 2.3 | 0.4 | 0.28 | 0.36
Fergus | 400 | -20 | -22 | 29 | 23 | 4300 | 28 | 108 | 760 | 0.9 | 925 | 160 | 2.2 | 0.4 | 0.28 | 0.36
Forest | 215 | -16 | -18 | 31 | 23 | 3740 | 25 | 103 | 810 | 1.0 | 875 | 160 | 2.0 | 0.4 | 0.37 | 0.48
Fort Erie | 180 | -15 | -17 | 30 | 24 | 3650 | 23 | 108 | 860 | 1.0 | 1020 | 160 | 2.3 | 0.4 | 0.36 | 0.46
Fort Erie (Ridgeway) | 190 | -15 | -17 | 30 | 24 | 3600 | 25 | 108 | 860 | 1.0 | 1000 | 160 | 2.3 | 0.4 | 0.36 | 0.46
Fort Frances | 340 | -33 | -35 | 29 | 22 | 5440 | 25 | 108 | 570 | 0.7 | 725 | 120 | 2.3 | 0.3 | 0.23 | 0.31
Gananoque | 80 | -22 | -24 | 28 | 23 | 4010 | 23 | 103 | 760 | 0.9 | 900 | 180 | 2.1 | 0.4 | 0.37 | 0.47
Geraldton | 345 | -36 | -39 | 28 | 21 | 6450 | 20 | 86 | 550 | 0.8 | 725 | 100 | 2.9 | 0.4 | 0.22 | 0.3
Glencoe | 215 | -16 | -18 | 31 | 24 | 3680 | 28 | 103 | 800 | 0.9 | 925 | 180 | 1.5 | 0.4 | 0.34 | 0.43
Goderich | 185 | -16 | -18 | 29 | 23 | 4000 | 25 | 92 | 810 | 1.0 | 950 | 180 | 2.4 | 0.4 | 0.37 | 0.48
Gore Bay | 205 | -24 | -26 | 28 | 22 | 4700 | 23 | 92 | 640 | 0.8 | 860 | 160 | 2.6 | 0.4 | 0.34 | 0.44
Graham | 495 | -35 | -37 | 29 | 22 | 5940 | 23 | 97 | 570 | 0.8 | 750 | 140 | 2.6 | 0.3 | 0.22 | 0.3
Gravenhurst (Muskoka Airport) | 255 | -26 | -28 | 29 | 23 | 4760 | 25 | 103 | 790 | 0.9 | 1050 | 120 | 2.7 | 0.4 | 0.28 | 0.36
Grimsby | 85 | -16 | -18 | 30 | 23 | 3520 | 23 | 108 | 760 | 0.9 | 875 | 160 | 0.9 | 0.4 | 0.36 | 0.46
Guelph | 340 | -19 | -21 | 29 | 23 | 4270 | 28 | 103 | 770 | 0.9 | 875 | 140 | 1.9 | 0.4 | 0.28 | 0.36
Guthrie | 280 | -24 | -26 | 29 | 23 | 4300 | 28 | 103 | 700 | 0.8 | 950 | 120 | 2.5 | 0.4 | 0.28 | 0.36
Haileybury | 210 | -32 | -35 | 30 | 22 | 5600 | 23 | 92 | 590 | 0.8 | 820 | 120 | 2.4 | 0.4 | 0.34 | 0.44
Haldimand (Caledonia) | 190 | -18 | -20 | 30 | 23 | 3750 | 23 | 108 | 810 | 0.9 | 875 | 160 | 1.2 | 0.4 | 0.34 | 0.44
Haldimand (Hagersville) | 215 | -17 | -19 | 30 | 23 | 3760 | 25 | 97 | 840 | 1.0 | 875 | 160 | 1.3 | 0.4 | 0.36 | 0.46
Haliburton | 335 | -27 | -29 | 29 | 23 | 4840 | 25 | 92 | 780 | 0.9 | 980 | 100 | 2.9 | 0.4 | 0.27 | 0.35
Halton Hills (Georgetown) | 255 | -19 | -21 | 30 | 23 | 4200 | 28 | 119 | 750 | 0.8 | 850 | 140 | 1.4 | 0.4 | 0.29 | 0.37
Hamilton — Above Escarpment - West of John C. Munro Int'l Airport | 240 | -17 | -19 | 31 | 23 | 3460 | 23 | 108 | 810 | 0.9 | 875 | 160 | 1.5 | 0.4 | 0.36 | 0.46
Hamilton — Above Escarpment - East of John C. Munro Int'l Airport | 200 | -17 | -19 | 31 | 23 | 3460 | 23 | 108 | 810 | 0.9 | 875 | 160 | 1.3 | 0.4 | 0.36 | 0.46
Hamilton — Below Escarpment - West of Highway 403 | 90 | -17 | -19 | 31 | 23 | 3460 | 23 | 108 | 810 | 0.9 | 875 | 160 | 1.1 | 0.4 | 0.36 | 0.46
Hamilton — Below Escarpment - East of Highway 403 | 90 | -17 | -19 | 31 | 23 | 3460 | 23 | 108 | 810 | 0.9 | 875 | 160 | 1.1 | 0.4 | 0.36 | 0.46
Hanover | 270 | -19 | -21 | 29 | 22 | 4300 | 28 | 103 | 790 | 0.9 | 1050 | 140 | 2.6 | 0.4 | 0.34 | 0.44
Hastings | 200 | -24 | -26 | 30 | 23 | 4280 | 25 | 92 | 730 | 0.9 | 840 | 140 | 2.0 | 0.4 | 0.32 | 0.41
Hawkesbury | 50 | -25 | -27 | 30 | 23 | 4610 | 23 | 103 | 800 | 0.9 | 925 | 160 | 2.3 | 0.4 | 0.32 | 0.41
Hearst | 245 | -35 | -37 | 29 | 21 | 6450 | 20 | 86 | 520 | 0.7 | 825 | 80 | 2.8 | 0.3 | 0.23 | 0.3
Honey Harbour | 180 | -24 | -26 | 29 | 23 | 4300 | 25 | 97 | 710 | 0.9 | 1050 | 160 | 2.7 | 0.4 | 0.3 | 0.39
Hornepayne | 360 | -37 | -40 | 28 | 21 | 6340 | 20 | 93 | 420 | 0.7 | 750 | 80 | 3.3 | 0.4 | 0.22 | 0.3
Huntsville | 335 | -26 | -29 | 29 | 22 | 4850 | 25 | 103 | 800 | 0.9 | 1000 | 120 | 2.9 | 0.4 | 0.27 | 0.35
Ingersoll | 280 | -18 | -20 | 30 | 23 | 3920 | 28 | 108 | 840 | 1.0 | 950 | 180 | 1.7 | 0.4 | 0.37 | 0.48
Iroquois Falls | 275 | -33 | -36 | 29 | 21 | 6100 | 20 | 86 | 575 | 0.8 | 825 | 100 | 2.9 | 0.3 | 0.29 | 0.37
Jellicoe | 330 | -36 | -39 | 28 | 21 | 6400 | 20 | 86 | 550 | 0.8 | 750 | 100 | 2.7 | 0.4 | 0.22 | 0.3
Kapuskasing | 245 | -34 | -36 | 29 | 21 | 6250 | 20 | 86 | 550 | 0.8 | 825 | 100 | 3.0 | 0.3 | 0.24 | 0.31
Kemptville | 90 | -25 | -27 | 30 | 23 | 4540 | 25 | 92 | 750 | 0.9 | 925 | 160 | 2.3 | 0.4 | 0.32 | 0.41
Kenora | 370 | -33 | -35 | 28 | 22 | 5630 | 25 | 113 | 515 | 0.6 | 630 | 120 | 2.5 | 0.3 | 0.23 | 0.31
Killaloe | 185 | -28 | -31 | 30 | 22 | 4960 | 23 | 86 | 680 | 0.8 | 825 | 120 | 2.7 | 0.4 | 0.27 | 0.35
Kincardine | 190 | -17 | -19 | 28 | 22 | 3890 | 25 | 92 | 800 | 1.0 | 950 | 180 | 2.6 | 0.4 | 0.37 | 0.48
Kingston | 80 | -22 | -24 | 28 | 23 | 4000 | 23 | 108 | 780 | 1.0 | 950 | 180 | 2.1 | 0.4 | 0.37 | 0.47
Kinmount | 295 | -26 | -28 | 29 | 23 | 4600 | 25 | 108 | 750 | 0.9 | 950 | 120 | 2.7 | 0.4 | 0.27 | 0.35
Kirkland Lake | 325 | -33 | -36 | 29 | 22 | 6000 | 23 | 92 | 600 | 0.8 | 875 | 100 | 2.9 | 0.3 | 0.3 | 0.39
Kitchener | 335 | -19 | -21 | 29 | 23 | 4200 | 28 | 119 | 780 | 0.9 | 925 | 140 | 2.0 | 0.4 | 0.29 | 0.37
Lakefield | 240 | -24 | -26 | 30 | 23 | 4330 | 25 | 92 | 720 | 0.9 | 850 | 140 | 2.2 | 0.4 | 0.3 | 0.38
Lansdowne House | 240 | -38 | -40 | 28 | 21 | 7150 | 23 | 92 | 500 | 0.8 | 680 | 140 | 3.0 | 0.2 | 0.24 | 0.32
Leamington | 190 | -15 | -17 | 31 | 24 | 3400 | 28 | 113 | 800 | 0.9 | 875 | 180 | 0.8 | 0.4 | 0.37 | 0.47
Lindsay | 265 | -24 | -26 | 30 | 23 | 4320 | 25 | 103 | 720 | 0.8 | 850 | 140 | 2.3 | 0.4 | 0.3 | 0.38
Lion's Head | 185 | -19 | -21 | 27 | 22 | 4300 | 25 | 103 | 700 | 0.9 | 950 | 180 | 2.7 | 0.4 | 0.37 | 0.48
Listowel | 380 | -19 | -21 | 29 | 23 | 4300 | 28 | 119 | 800 | 0.9 | 1000 | 160 | 2.6 | 0.4 | 0.34 | 0.43
London | 245 | -18 | -20 | 30 | 24 | 3900 | 28 | 103 | 825 | 0.9 | 975 | 180 | 1.9 | 0.4 | 0.37 | 0.47
Lucan | 300 | -17 | -19 | 30 | 23 | 3900 | 25 | 113 | 810 | 0.9 | 1000 | 180 | 2.3 | 0.4 | 0.37 | 0.48
Maitland | 85 | -23 | -25 | 29 | 23 | 4080 | 25 | 103 | 770 | 0.9 | 975 | 180 | 2.2 | 0.4 | 0.34 | 0.44
Markdale | 425 | -20 | -22 | 29 | 22 | 4500 | 28 | 103 | 820 | 0.9 | 1050 | 160 | 3.2 | 0.4 | 0.32 | 0.41
Markham | 175 | -21 | -23 | 31 | 24 | 4000 | 25 | 86 | 720 | 0.8 | 825 | 140 | 1.3 | 0.4 | 0.34 | 0.44
Martin | 485 | -35 | -37 | 29 | 22 | 5900 | 25 | 103 | 560 | 0.8 | 750 | 120 | 2.6 | 0.3 | 0.22 | 0.3
Matheson | 265 | -33 | -36 | 29 | 21 | 6080 | 20 | 86 | 580 | 0.8 | 825 | 100 | 2.8 | 0.3 | 0.3 | 0.39
Mattawa | 165 | -29 | -31 | 30 | 22 | 5050 | 23 | 86 | 700 | 0.9 | 875 | 100 | 2.1 | 0.4 | 0.25 | 0.32
Midland | 190 | -24 | -26 | 29 | 23 | 4200 | 25 | 97 | 740 | 0.9 | 1060 | 160 | 2.7 | 0.4 | 0.3 | 0.39
Milton | 200 | -18 | -20 | 30 | 23 | 3920 | 25 | 125 | 750 | 0.9 | 850 | 160 | 1.3 | 0.4 | 0.34 | 0.43
Milverton | 370 | -19 | -21 | 29 | 23 | 4200 | 28 | 108 | 800 | 0.9 | 1050 | 160 | 2.4 | 0.4 | 0.34 | 0.43
Minden | 270 | -27 | -29 | 29 | 23 | 4640 | 25 | 97 | 780 | 0.9 | 1010 | 100 | 2.7 | 0.4 | 0.27 | 0.35
Mississauga | 160 | -18 | -20 | 30 | 23 | 3880 | 25 | 113 | 720 | 0.9 | 800 | 160 | 1.1 | 0.4 | 0.34 | 0.44
Mississauga (Lester B. Pearson International Airport) | 170 | -20 | -22 | 31 | 24 | 3890 | 26 | 108 | 685 | 0.8 | 790 | 160 | 1.1 | 0.4 | 0.34 | 0.44
Mississauga (Port Credit) | 75 | -18 | -20 | 29 | 23 | 3780 | 25 | 108 | 720 | 0.9 | 800 | 160 | 0.9 | 0.4 | 0.37 | 0.48
Mitchell | 335 | -18 | -20 | 29 | 23 | 4100 | 28 | 113 | 810 | 0.9 | 1050 | 160 | 2.4 | 0.4 | 0.35 | 0.45
Moosonee | 10 | -36 | -38 | 28 | 22 | 6800 | 18 | 81 | 500 | 0.8 | 700 | 160 | 2.7 | 0.3 | 0.26 | 0.35
Morrisburg | 75 | -23 | -25 | 30 | 23 | 4370 | 25 | 103 | 800 | 0.9 | 950 | 180 | 2.3 | 0.4 | 0.32 | 0.41
Mount Forest | 420 | -21 | -24 | 28 | 22 | 4700 | 28 | 103 | 740 | 0.9 | 940 | 140 | 2.7 | 0.4 | 0.32 | 0.41
Nakina | 325 | -36 | -38 | 28 | 21 | 6500 | 20 | 86 | 540 | 0.8 | 750 | 100 | 2.8 | 0.4 | 0.22 | 0.3
Nanticoke (Jarvis) | 205 | -17 | -18 | 30 | 23 | 3700 | 28 | 108 | 840 | 1.0 | 900 | 160 | 1.4 | 0.4 | 0.37 | 0.48
Nanticoke (Port Dover) | 180 | -15 | -17 | 30 | 24 | 3600 | 25 | 108 | 860 | 1.0 | 950 | 140 | 1.2 | 0.4 | 0.37 | 0.48
Napanee | 90 | -22 | -24 | 29 | 23 | 4140 | 23 | 92 | 770 | 0.9 | 900 | 160 | 1.9 | 0.4 | 0.34 | 0.43
Newcastle | 115 | -20 | -22 | 30 | 23 | 3990 | 23 | 86 | 760 | 0.9 | 830 | 160 | 1.5 | 0.4 | 0.37 | 0.48
Newcastle (Bowmanville) | 95 | -20 | -22 | 30 | 23 | 4000 | 23 | 86 | 760 | 0.9 | 830 | 160 | 1.4 | 0.4 | 0.37 | 0.48
New Liskeard | 180 | -32 | -35 | 30 | 22 | 5570 | 23 | 92 | 570 | 0.8 | 810 | 100 | 2.6 | 0.4 | 0.34 | 0.43
Newmarket | 185 | -22 | -24 | 30 | 23 | 4260 | 28 | 108 | 700 | 0.8 | 800 | 140 | 2.0 | 0.4 | 0.3 | 0.38
Niagara Falls | 210 | -16 | -18 | 30 | 23 | 3600 | 23 | 96 | 810 | 0.9 | 950 | 160 | 1.8 | 0.4 | 0.34 | 0.43
North Bay | 210 | -28 | -30 | 28 | 22 | 5150 | 25 | 95 | 775 | 0.9 | 975 | 120 | 2.2 | 0.4 | 0.27 | 0.34
Norwood | 225 | -24 | -26 | 30 | 23 | 4320 | 25 | 92 | 720 | 0.8 | 850 | 120 | 2.1 | 0.4 | 0.32 | 0.41
Oakville | 90 | -18 | -20 | 30 | 23 | 3760 | 23 | 97 | 750 | 0.9 | 850 | 160 | 1.1 | 0.4 | 0.37 | 0.47
Orangeville | 430 | -21 | -23 | 29 | 23 | 4450 | 28 | 108 | 730 | 0.8 | 875 | 140 | 2.3 | 0.4 | 0.28 | 0.36
Orillia | 230 | -25 | -27 | 29 | 23 | 4260 | 25 | 103 | 740 | 0.9 | 1000 | 120 | 2.4 | 0.4 | 0.28 | 0.36
Oshawa | 110 | -19 | -21 | 30 | 23 | 3860 | 23 | 86 | 760 | 0.9 | 875 | 160 | 1.4 | 0.4 | 0.37 | 0.48
Ottawa (Barrhaven) | 98 | -25 | -27 | 30 | 23 | 4500 | 25 | 92 | 750 | 0.8 | 900 | 160 | 2.4 | 0.4 | 0.32 | 0.41
Ottawa (City Hall) | 70 | -25 | -27 | 30 | 23 | 4440 | 23 | 86 | 750 | 0.8 | 900 | 160 | 2.4 | 0.4 | 0.32 | 0.41
Ottawa (Kanata) | 98 | -25 | -27 | 30 | 23 | 4520 | 25 | 92 | 730 | 0.8 | 900 | 160 | 2.5 | 0.4 | 0.32 | 0.41
Ottawa (MacDonald-Cartier Int'l Airport) | 125 | -25 | -27 | 30 | 23 | 4500 | 24 | 89 | 750 | 0.8 | 900 | 160 | 2.4 | 0.4 | 0.32 | 0.41
Ottawa (Orleans) | 70 | -26 | -28 | 30 | 23 | 4500 | 23 | 91 | 750 | 0.8 | 900 | 160 | 2.4 | 0.4 | 0.32 | 0.41
Owen Sound | 215 | -19 | -21 | 29 | 22 | 4030 | 28 | 113 | 760 | 0.9 | 1075 | 160 | 2.8 | 0.4 | 0.34 | 0.44
Pagwa River | 185 | -35 | -37 | 28 | 21 | 6500 | 20 | 86 | 540 | 0.8 | 825 | 80 | 2.7 | 0.4 | 0.22 | 0.3
Paris | 245 | -18 | -20 | 30 | 23 | 4000 | 23 | 96 | 790 | 0.9 | 925 | 160 | 1.4 | 0.4 | 0.33 | 0.42
Parkhill | 205 | -16 | -18 | 31 | 23 | 3800 | 25 | 103 | 800 | 0.9 | 925 | 180 | 2.1 | 0.4 | 0.37 | 0.48
Parry Sound | 215 | -24 | -26 | 28 | 22 | 4640 | 23 | 97 | 820 | 1.0 | 1050 | 160 | 2.8 | 0.4 | 0.3 | 0.39
Pelham (Fonthill) | 230 | -15 | -17 | 30 | 23 | 3690 | 23 | 96 | 820 | 0.9 | 950 | 160 | 2.1 | 0.4 | 0.33 | 0.42
Pembroke | 125 | -28 | -31 | 30 | 23 | 4980 | 23 | 105 | 640 | 0.8 | 825 | 100 | 2.5 | 0.4 | 0.27 | 0.35
Penetanguishene | 220 | -24 | -26 | 29 | 23 | 4200 | 25 | 97 | 720 | 0.9 | 1050 | 160 | 2.8 | 0.4 | 0.3 | 0.39
Perth | 130 | -25 | -27 | 30 | 23 | 4540 | 25 | 92 | 730 | 0.8 | 900 | 140 | 2.3 | 0.4 | 0.32 | 0.41
Petawawa | 135 | -29 | -31 | 30 | 23 | 4980 | 23 | 92 | 640 | 0.8 | 825 | 100 | 2.6 | 0.4 | 0.27 | 0.35
Peterborough | 200 | -23 | -25 | 30 | 23 | 4400 | 25 | 92 | 710 | 0.8 | 840 | 140 | 2.0 | 0.4 | 0.32 | 0.41
Petrolia | 195 | -16 | -18 | 31 | 24 | 3640 | 25 | 108 | 810 | 0.9 | 920 | 180 | 1.3 | 0.4 | 0.37 | 0.47
Pickering Zone 1 | 85 | -19 | -21 | 30 | 23 | 3800 | 23 | 92 | 730 | 0.9 | 825 | 140 | 1.0 | 0.4 | 0.37 | 0.48
Pickering Zone 2 | 175 | -20 | -22 | 30 | 23 | 3900 | 23 | 92 | 730 | 0.9 | 825 | 140 | 1.5 | 0.4 | 0.37 | 0.48
Pickering Zone 3 | 255 | -21 | -23 | 30 | 23 | 4010 | 23 | 86 | 770 | 0.91 | 850 | 140 | 1.9 | 0.4 | 0.35 | 0.45
Pickering Zone 4 | 315 | -22 | -24 | 30 | 23 | 4200 | 23 | 86 | 770 | 0.91 | 850 | 140 | 2.3 | 0.4 | 0.35 | 0.45
Picton | 95 | -21 | -23 | 29 | 23 | 3980 | 23 | 92 | 770 | 0.9 | 940 | 160 | 2.0 | 0.4 | 0.38 | 0.49
Plattsville | 300 | -19 | -21 | 29 | 23 | 4150 | 28 | 103 | 820 | 0.9 | 950 | 140 | 1.9 | 0.4 | 0.33 | 0.42
Point Alexander | 150 | -29 | -32 | 30 | 22 | 4960 | 23 | 92 | 650 | 0.8 | 850 | 100 | 2.5 | 0.4 | 0.27 | 0.35
Port Burwell | 195 | -15 | -17 | 30 | 24 | 3800 | 25 | 92 | 930 | 1.1 | 1000 | 180 | 1.2 | 0.4 | 0.37 | 0.47
Port Colborne | 180 | -15 | -17 | 30 | 24 | 3600 | 23 | 108 | 850 | 1.0 | 1000 | 160 | 2.1 | 0.4 | 0.36 | 0.46
Port Elgin | 205 | -17 | -19 | 28 | 22 | 4100 | 25 | 92 | 790 | 0.9 | 850 | 180 | 2.8 | 0.4 | 0.37 | 0.48
Port Hope | 100 | -21 | -23 | 29 | 23 | 3970 | 23 | 94 | 760 | 0.9 | 825 | 180 | 1.2 | 0.4 | 0.37 | 0.48
Port Perry | 270 | -22 | -24 | 30 | 23 | 4260 | 25 | 97 | 720 | 0.8 | 850 | 140 | 2.4 | 0.4 | 0.34 | 0.44
Port Stanley | 180 | -15 | -17 | 31 | 24 | 3850 | 25 | 92 | 940 | 1.1 | 975 | 180 | 1.2 | 0.4 | 0.37 | 0.47
Prescott | 90 | -23 | -25 | 29 | 23 | 4120 | 25 | 103 | 770 | 0.9 | 975 | 180 | 2.2 | 0.4 | 0.34 | 0.44
Princeton | 280 | -18 | -20 | 30 | 23 | 4000 | 25 | 97 | 810 | 0.9 | 925 | 160 | 1.5 | 0.4 | 0.33 | 0.42
Raith | 475 | -34 | -37 | 28 | 22 | 5900 | 23 | 97 | 570 | 0.8 | 750 | 120 | 2.7 | 0.4 | 0.22 | 0.3
Rayside-Balfour (Chelmsford) | 270 | -28 | -30 | 29 | 21 | 5200 | 25 | 92 | 650 | 0.8 | 850 | 180 | 2.5 | 0.4 | 0.35 | 0.45
Red Lake | 360 | -35 | -37 | 28 | 21 | 6220 | 20 | 92 | 470 | 0.7 | 630 | 120 | 2.6 | 0.3 | 0.22 | 0.3
Renfrew | 115 | -27 | -30 | 30 | 23 | 4900 | 23 | 97 | 620 | 0.8 | 810 | 140 | 2.5 | 0.4 | 0.27 | 0.35
Richmond Hill | 230 | -21 | -23 | 31 | 24 | 4000 | 25 | 97 | 740 | 0.8 | 850 | 140 | 1.5 | 0.4 | 0.34 | 0.44
Rockland | 50 | -26 | -28 | 30 | 23 | 4600 | 23 | 92 | 780 | 0.9 | 950 | 160 | 2.4 | 0.4 | 0.31 | 0.4
Sarnia | 190 | -16 | -18 | 31 | 24 | 3750 | 25 | 100 | 750 | 0.9 | 825 | 180 | 1.1 | 0.4 | 0.37 | 0.47
Sault Ste. Marie | 190 | -25 | -28 | 29 | 22 | 4960 | 23 | 97 | 660 | 0.9 | 950 | 200 | 3.1 | 0.4 | 0.33 | 0.44
Schreiber | 310 | -34 | -36 | 27 | 21 | 5960 | 20 | 103 | 600 | 0.8 | 850 | 160 | 3.3 | 0.4 | 0.29 | 0.39
Seaforth | 310 | -17 | -19 | 30 | 23 | 4100 | 25 | 108 | 810 | 0.9 | 1025 | 160 | 2.5 | 0.4 | 0.35 | 0.45
Shelburne | 495 | -22 | -24 | 29 | 23 | 4700 | 28 | 108 | 740 | 0.9 | 900 | 150 | 3.1 | 0.4 | 0.31 | 0.4
Simcoe | 210 | -17 | -19 | 30 | 24 | 3700 | 28 | 113 | 860 | 1.0 | 950 | 160 | 1.3 | 0.4 | 0.35 | 0.45
Sioux Lookout | 375 | -34 | -36 | 28 | 22 | 5950 | 25 | 97 | 520 | 0.7 | 710 | 100 | 2.6 | 0.3 | 0.22 | 0.3
Smiths Falls | 130 | -25 | -27 | 30 | 23 | 4540 | 25 | 92 | 730 | 0.8 | 850 | 140 | 2.3 | 0.4 | 0.32 | 0.41
Smithville | 185 | -16 | -18 | 30 | 23 | 3650 | 23 | 108 | 800 | 0.9 | 900 | 160 | 1.5 | 0.4 | 0.33 | 0.42
Smooth Rock Falls | 235 | -34 | -36 | 29 | 21 | 6250 | 20 | 92 | 560 | 0.8 | 850 | 80 | 2.7 | 0.3 | 0.25 | 0.32
Southampton | 180 | -17 | -19 | 28 | 22 | 4100 | 25 | 92 | 800 | 1.0 | 830 | 180 | 2.7 | 0.4 | 0.37 | 0.48
South River | 355 | -27 | -29 | 29 | 22 | 5090 | 25 | 103 | 830 | 1.0 | 975 | 120 | 2.8 | 0.4 | 0.27 | 0.35
St. Catharines | 105 | -16 | -18 | 30 | 23 | 3540 | 23 | 92 | 770 | 0.9 | 850 | 160 | 1.0 | 0.4 | 0.36 | 0.46
St. Mary's | 310 | -18 | -20 | 30 | 23 | 4000 | 28 | 108 | 820 | 1.0 | 1025 | 160 | 2.2 | 0.4 | 0.37 | 0.47
St. Thomas | 225 | -16 | -18 | 31 | 24 | 3780 | 25 | 103 | 900 | 1.0 | 975 | 180 | 1.4 | 0.4 | 0.37 | 0.47
Stirling | 120 | -23 | -25 | 30 | 23 | 4220 | 25 | 97 | 740 | 0.9 | 850 | 120 | 1.7 | 0.4 | 0.31 | 0.4
Stratford | 360 | -18 | -20 | 29 | 23 | 4050 | 28 | 113 | 820 | 1.0 | 1050 | 160 | 2.3 | 0.4 | 0.35 | 0.45
Strathroy | 225 | -17 | -19 | 31 | 24 | 3780 | 25 | 103 | 770 | 0.9 | 950 | 180 | 1.9 | 0.4 | 0.37 | 0.47
Sturgeon Falls | 205 | -28 | -30 | 29 | 21 | 5200 | 25 | 95 | 700 | 0.9 | 910 | 140 | 2.4 | 0.4 | 0.27 | 0.35
Sudbury | 275 | -28 | -30 | 29 | 21 | 5180 | 25 | 97 | 650 | 0.8 | 875 | 200 | 2.5 | 0.4 | 0.36 | 0.46
Sundridge | 340 | -27 | -29 | 29 | 22 | 5080 | 25 | 97 | 840 | 1.0 | 975 | 120 | 2.8 | 0.4 | 0.27 | 0.35
Tavistock | 340 | -19 | -21 | 29 | 23 | 4100 | 28 | 113 | 820 | 1.0 | 1010 | 160 | 2.1 | 0.4 | 0.35 | 0.45
Temagami | 300 | -30 | -33 | 30 | 22 | 5420 | 23 | 92 | 650 | 0.8 | 875 | 120 | 2.6 | 0.4 | 0.29 | 0.37
Thamesford | 280 | -19 | -21 | 30 | 23 | 3950 | 28 | 108 | 820 | 0.9 | 975 | 160 | 1.9 | 0.4 | 0.37 | 0.48
Thedford | 205 | -16 | -18 | 31 | 23 | 3710 | 25 | 103 | 810 | 1.0 | 900 | 180 | 2.1 | 0.4 | 0.37 | 0.48
Thunder Bay | 210 | -31 | -33 | 29 | 21 | 5650 | 23 | 108 | 560 | 0.8 | 710 | 160 | 2.9 | 0.4 | 0.29 | 0.39
Tillsonburg | 215 | -17 | -19 | 30 | 24 | 3840 | 25 | 103 | 880 | 1.0 | 980 | 160 | 1.3 | 0.4 | 0.34 | 0.44
Timmins | 300 | -34 | -36 | 29 | 21 | 5940 | 20 | 108 | 560 | 0.8 | 875 | 100 | 3.1 | 0.3 | 0.27 | 0.35
Timmins (Porcupine) | 295 | -34 | -36 | 29 | 21 | 6000 | 20 | 103 | 560 | 0.8 | 875 | 100 | 2.9 | 0.3 | 0.29 | 0.37
Toronto Metropolitan Region — Etobicoke | 160 | -20 | -22 | 31 | 24 | 3800 | 26 | 108 | 720 | 0.8 | 800 | 160 | 1.1 | 0.4 | 0.34 | 0.44
Toronto Metropolitan Region — North York | 175 | -20 | -22 | 31 | 24 | 3760 | 25 | 108 | 730 | 0.8 | 850 | 150 | 1.2 | 0.4 | 0.34 | 0.44
Toronto Metropolitan Region — Scarborough | 180 | -20 | -22 | 31 | 24 | 3800 | 25 | 92 | 730 | 0.9 | 825 | 160 | 1.2 | 0.4 | 0.37 | 0.47
Toronto Metropolitan Region — Toronto (City Hall) | 90 | -18 | -20 | 31 | 23 | 3520 | 25 | 97 | 720 | 0.9 | 820 | 160 | 0.9 | 0.4 | 0.34 | 0.44
Trenton | 80 | -22 | -24 | 29 | 23 | 4110 | 23 | 97 | 760 | 0.9 | 850 | 160 | 1.6 | 0.4 | 0.37 | 0.47
Trout Creek | 330 | -27 | -29 | 29 | 22 | 5100 | 25 | 103 | 780 | 0.9 | 975 | 120 | 2.7 | 0.4 | 0.27 | 0.35
Uxbridge | 275 | -22 | -24 | 30 | 23 | 4240 | 25 | 103 | 700 | 0.8 | 850 | 140 | 2.4 | 0.4 | 0.33 | 0.42
Vaughan (Woodbridge) | 165 | -20 | -22 | 31 | 24 | 4100 | 26 | 113 | 700 | 0.8 | 800 | 140 | 1.1 | 0.4 | 0.34 | 0.44
Vittoria | 215 | -15 | -17 | 30 | 24 | 3680 | 25 | 113 | 880 | 1.0 | 950 | 160 | 1.3 | 0.4 | 0.37 | 0.47
Walkerton | 275 | -18 | -20 | 30 | 22 | 4300 | 28 | 103 | 790 | 0.9 | 1025 | 160 | 2.7 | 0.4 | 0.36 | 0.46
Wallaceburg | 180 | -16 | -18 | 31 | 24 | 3600 | 28 | 97 | 760 | 0.9 | 825 | 180 | 0.9 | 0.4 | 0.35 | 0.45
Waterloo | 330 | -19 | -21 | 29 | 23 | 4200 | 28 | 119 | 780 | 0.9 | 925 | 160 | 2.0 | 0.4 | 0.29 | 0.37
Watford | 240 | -17 | -19 | 31 | 24 | 3740 | 25 | 108 | 790 | 0.9 | 950 | 160 | 1.9 | 0.4 | 0.37 | 0.47
Wawa | 290 | -34 | -36 | 26 | 21 | 5840 | 20 | 93 | 725 | 0.9 | 950 | 160 | 3.4 | 0.4 | 0.3 | 0.39
Welland | 180 | -15 | -17 | 30 | 23 | 3670 | 23 | 103 | 840 | 1.0 | 975 | 160 | 2.0 | 0.4 | 0.34 | 0.43
West Lorne | 215 | -16 | -18 | 31 | 24 | 3700 | 28 | 103 | 840 | 1.0 | 900 | 180 | 1.3 | 0.4 | 0.37 | 0.47
Whitby | 85 | -20 | -22 | 30 | 23 | 3820 | 23 | 86 | 760 | 0.9 | 850 | 160 | 1.2 | 0.4 | 0.37 | 0.48
Whitby (Brooklin) | 160 | -20 | -22 | 30 | 23 | 4010 | 23 | 86 | 770 | 0.9 | 850 | 140 | 1.9 | 0.4 | 0.35 | 0.45
White River | 375 | -39 | -42 | 28 | 21 | 6150 | 20 | 92 | 575 | 0.8 | 825 | 100 | 3.6 | 0.4 | 0.22 | 0.3
Wiarton | 185 | -19 | -21 | 29 | 22 | 4300 | 25 | 103 | 740 | 0.9 | 1000 | 180 | 2.7 | 0.4 | 0.34 | 0.44
Windsor | 185 | -16 | -18 | 32 | 24 | 3400 | 28 | 103 | 800 | 0.9 | 900 | 180 | 0.8 | 0.4 | 0.37 | 0.47
Wingham | 310 | -18 | -20 | 30 | 23 | 4220 | 28 | 108 | 780 | 0.9 | 1050 | 160 | 2.6 | 0.4 | 0.36 | 0.46
Woodstock | 300 | -19 | -21 | 30 | 23 | 3910 | 28 | 113 | 830 | 0.9 | 930 | 160 | 1.9 | 0.4 | 0.34 | 0.44
Wyoming | 215 | -16 | -18 | 31 | 24 | 3700 | 25 | 103 | 815 | 0.9 | 900 | 180 | 1.6 | 0.4 | 0.37 | 0.47
Open OBC SB-1 in the code viewer
OBC Div. B 7.4.10.5. Conversion of Fixture Units to Litres and Gal/min
(1)Except as provided in Sentence 7.4.10.3.(2), where the hydraulic load is to be expressed in litres, fixture units shall be converted as follows:
(a)when the number of fixture units is 260 or fewer, the load is 2,360 L, and
(b)when the number of fixture units exceeds 260, the load is 9.1 L for each fixture unit.
(2)Where the hydraulic load is to be expressed in gal/min, fixture units shall be converted in accordance with Table 7.4.10.5.
Open OBC Div. B 7.4.10.5. in the code viewer
OBC Div. B 7.6.3.4. Size
(1)Water service pipes shall be sized according to the peak demand flow but shall not be less than NPS3/4 .
(2)Except as provided in Sentence (3), the nominal pipe size of a supply pipe that serves a fixture shall conform to Table 7.6.3.2.-A.
(3)For fixtures listed in Table 7.6.3.2.-A that are permitted to have an NPS3/8 supply pipe, a connector not more than 750 mm long and not less than NPS1/4 may be used to supply water to the fixture.
(4)No water system between the point of connection with the water service pipe or the water meter and the first water distribution pipe that supplies a water heater that serves more than one fixture shall be sized less than NPS 3/4.
(5)Except as permitted in Sentence (6), where both hot and cold water is supplied to fixtures in residential buildings containing one or two dwelling units or row houses with separate water service pipes, the water system may be sized in accordance with Table 7.6.3.4., where
(a)the hydraulic loads for maximum separate demands on water distribution system piping are not less than 100% of the total hydraulic load of the fixture units given in Table 7.6.3.2.-A, 7.6.3.2.-B, 7.6.3.2.-C or 7.6.3.2.-D for private use.
(b)the minimum water pressure at the entry to the building is 200 kPa, and
(c)the total maximum length of the water system is 90 m.
(See Note A-7.6.3.4.(5))
(6)Where both hot and cold water is supplied to fixtures in a house containing only one dwelling unit, the water service pipe is permitted to be a minimum of NPS ¾ in provided,
(a)a minimum NPS ¾ water supply piping located in the basement or lower level is extended to the base of every hot and cold riser that serves a maximum of one bathroom group and to the last water supply branch serving any basement bathroom group, fixture supply or hose bibb, and
(b)the total hydraulic load is not more than 26 fixture units, using the values given in Table 7.6.3.2.-A.
Open OBC Div. B 7.6.3.4. in the code viewer
OBC Div. B Table 7.6.3.4. Hydraulic Load, Fixture Units
Table 7.6.3.4. — Hydraulic Load, Fixture Units Forming Part of Sentence 7.6.3.4.(5) Nominal Pipe Size of Water Pipe, NPS | Water Velocity, 3.0 m/s[1]: Hydraulic Load, fixture units | Water Velocity, 2.4 m/s[1]: Hydraulic Load, fixture units | Water Velocity, 1.5 m/s[1]: Hydraulic Load, fixture units ½ | 8 | 7 | 4 ¾ | 21 | 16 | 9 1 | 43 | 31 | 18 1¼ | 83 | 57 | 30 Notes to Table 7.6.3.4.: (1) Table 2.6.3.4. is not intended to limit water velocities that are permitted by Sentence 7.6.3.5.(1).
Open OBC Div. B Table 7.6.3.4. in the code viewer
OBC Div. B 7.5.6.3. Location of Vent Pipes
(1)Except as provided in Sentences (2) and (3), vent pipes that protects a fixture trap shall be located so that
(a)the developed length of the trap arm is not less than twice the NPS of the fixture drain,
(b)the total fall of the trap arm is not greater than its inside diameter, and
(c)the trap arm does not have a cumulative change in direction of more than 135°.
(2)The trap arm of water closets, of S-trap standards or of any other fixture that also discharges vertically and depends on siphonic action for its proper functioning shall not have a cumulative change in direction of more than 225°.
(3)A vent pipe that protects a water closet or any other fixture that also depends on siphonic action for its proper functioning shall be located so that the distance between the connections of the fixture drain to the fixture and the vent pipe does not exceed
(a)1 m in the vertical plane, and
(b)3 m in the horizontal plane.
(4)The maximum length of every trap arm shall conform to Table 7.5.6.3.
Open OBC Div. B 7.5.6.3. in the code viewer
OBC Div. B 7.5.7.2. Size Restriction
(1)The nominal pipe size of a branch vent, stack vent, vent stack or vent header shall be not less than the nominal pipe size of the vent pipe to which it is connected.
(2)Sanitary building drains shall be provided with at least one vent that is not less than NPS 3.
(3)A vent referred to in Sentence (2) shall be a soil stack if one is available and may be a vent stack or waste stack that provides at least NPS 3 stack vent and that goes to open air above the roof, either directly or through a header.
Open OBC Div. B 7.5.7.2. in the code viewer