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Values this chapter turns on
- permitted for treated rainwater supply
- 9 uses
- permitted for treated rainwater supply
- permitted for treated greywater or storm sewage
- 4 uses
- permitted for treated greywater or storm sewage
- minimum set required in every dwelling unit
- 4 fixtures
- minimum set required in every dwelling unit
- non-dwelling room types that need a floor drain
- 4 rooms
- non-dwelling room types that need a floor drain
Section 7.1. sets the ground rules for every plumbing system: what Part 7 covers, which facilities are required, where each system must connect, and a few location rules. The section is short, so exam questions tend to test exact wording: which systems can connect where, and which floor drain rule applies.
Scope, application and definitions
The scope of Part 7 is set in Div. A Subsection 1.3.3. (OBC Div. B 7.1.0.1.OBC Div. B 7.1.0.1. Scope(1) The scope of this Part shall be as described in Subsection 1.3.3. of Division A.). Part 7 applies to the design and construction of plumbing (OBC Div. B 7.1.1.1.OBC Div. B 7.1.1.1. Application(1) Except as provided in Sentence (2), this Part applies to the design and construction of plumbing. (2) This Part does not apply to industrial process systems unless the industrial process system is interconnected with the plumbing system, in which case the interconnection shall be so designed and installed so that…). It does not apply to industrial process systems, unless one is interconnected with the plumbing system. In that case the interconnection must protect the plumbing system from contamination or malfunction.
Italic words carry the Div. A 1.4.1.2. definitions. Part 7 adds one local definition: a storey is the interval between two successive floor levels, including mezzanine floors that contain plumbing fixtures, or between a floor level and the roof (OBC Div. B 7.1.1A.1.OBC Div. B 7.1.1A.1. Definitions(1) Except as provided in Sentence (2), words that appear in italics are defined in Article 1.4.1.2. of Division A and in the Building Code Act, 1992. (2) In this Part, Storey means the interval between two successive floor levels including mezzanine floors that contain plumbing fixtures or between a floor level and…). This matters when counting storeys for stack, wet vent and vent stack rules.
Plumbing facilities
Required facilities come from Subsection 3.7.4. and Section 9.31. (OBC Div. B 7.1.1B.1.OBC Div. B 7.1.1B.1. Facilities Required(1) Plumbing facilities shall be provided in accordance with Subsection 3.7.4. and Section 9.31.). For a house that means a kitchen sink, lavatory, water closet and bathtub or shower.
Floor drains in houses are a favourite question (OBC Div. B 7.1.1B.2.OBC Div. B 7.1.1B.2. Floor Drains(1) Where gravity drainage to a sanitary drainage system is possible, a floor drain shall be installed in a basement forming part of a dwelling unit. (2) Where gravity drainage to a sanitary drainage system is not possible, the floor drain required by Sentence (1) may be connected to a storm drainage system, dry well…):
| Situation | Rule |
|---|---|
| Basement of a dwelling unit, gravity drainage to the sanitary system possible | floor drain required |
| Gravity drainage to the sanitary system not possible | the floor drain may go to a storm system, dry well or drainage ditch, if it can only receive clear-water waste or storm sewage |
| Laundry, garbage, incinerator, boiler or heating room not inside a dwelling unit | floor drain required |
Service connections
| System | Must connect to (7.1.2.OBC Div. B 7.1.2.1. Sanitary Drainage Systems(1) Except as provided in Section 7.7., sanitary drainage systems shall be connected to a public sanitary sewer, a public combined sewer or a private sewage disposal system. (2) A combined building drain or a combined building sewer shall not be installed. (See Note A-7.1.2.1.(2))) |
|---|---|
| Sanitary drainage | public sanitary sewer, public combined sewer or private sewage disposal system (7.1.2.1.OBC Div. B 7.1.2.1. Sanitary Drainage Systems(1) Except as provided in Section 7.7., sanitary drainage systems shall be connected to a public sanitary sewer, a public combined sewer or a private sewage disposal system. (2) A combined building drain or a combined building sewer shall not be installed. (See Note A-7.1.2.1.(2))) |
| Storm drainage | public storm sewer, public combined sewer or designated storm water disposal location (7.1.2.2.OBC Div. B 7.1.2.2. Storm Drainage Systems(1) Except as provided in Section 7.7., storm drainage systems and private sewers conveying storm sewage shall be connected to a public storm sewer, a public combined sewer or a designated storm water disposal location.) |
| Water distribution | public water main, drinking water system or potable private water supply (7.1.2.3.OBC Div. B 7.1.2.3. Water Distribution Systems(1) Except as provided in Section 7.7. and Sentences (2) and (3), water distribution systems shall be connected to a public water main, drinking water system or a potable private water supply system. (2) Storm sewage or greywater that is free of solids and treated to conform to Article 7.7.4.1. is permitted to be used…) |
A combined building drain or combined building sewer must not be installed (7.1.2.1.(2)OBC Div. B 7.1.2.1. Sanitary Drainage Systems(1) Except as provided in Section 7.7., sanitary drainage systems shall be connected to a public sanitary sewer, a public combined sewer or a private sewage disposal system. (2) A combined building drain or a combined building sewer shall not be installed. (See Note A-7.1.2.1.(2))). Sanitary and storm piping stay separate inside the property even if the street sewer is combined.
Non-potable sources are allowed for limited uses (OBC Div. B 7.1.2.3.OBC Div. B 7.1.2.3. Water Distribution Systems(1) Except as provided in Section 7.7. and Sentences (2) and (3), water distribution systems shall be connected to a public water main, drinking water system or a potable private water supply system. (2) Storm sewage or greywater that is free of solids and treated to conform to Article 7.7.4.1. is permitted to be used…), provided the water is free of solids and treated to 7.7.4.1.:
| Source | Permitted uses |
|---|---|
| Storm sewage or greywater | water closets, urinals, sub-surface irrigation, trap priming |
| Rainwater | the four above, plus clothes washers, laundry trays, mop sinks, bedpan washers and hose bibbs |
The longer list for rainwater is a common trick. Greywater cannot supply a clothes washer or hose bibb under this Sentence.
Separate services
Each building connected to public services gets its own connection (OBC Div. B 7.1.2.4.OBC Div. B 7.1.2.4. Separate Services(1) Except as provided in Sentences (2) and (3), piping in any building connected to the public services shall be connected separately from piping of any other building, except that an ancillary building on the same property may be served by the same service. (See Note A-7.1.2.4.(1)) (2) No plumbing serving a dwelling…). The exception that matters for houses: an ancillary building on the same property may share the service, so a detached garage with a sink can be fed from the house. Plumbing serving one dwelling unit must not run in or under another unit unless it is in a tunnel, pipe corridor, common basement or parking garage where it stays accessible. Plumbing serving an upper unit may still run in or under the unit below.
Location of fixtures, movement and seismic design
- Fixtures may only be installed in rooms that are lighted and ventilated under Parts 3, 6 and 9 (OBC Div. B 7.1.3.1.OBC Div. B 7.1.3.1. Lighting and Ventilation Requirements(1) Plumbing fixtures shall not be installed in a room that is not lighted and ventilated in accordance with the appropriate requirements in Parts 3, 6 and 9.).
- Every fixture, plumbing appliance, interceptor, cleanout, valve, device or piece of equipment must be readily accessible for use, cleaning and maintenance (OBC Div. B 7.1.3.2.OBC Div. B 7.1.3.2. Accessibility(1) Every fixture, plumbing appliance, interceptor, cleanout, valve, device or piece of equipment shall be located so that it is readily accessible for use, cleaning and maintenance.). The definition of accessible says that needing to cut or break materials to reach an item means it is not accessible (def.OBC Div. A 1.4.1.2.(1) AccessibleAccessible means, when applied to a fixture, connection, plumbing appliance, valve, cleanout or equipment, to be accessible with or without having to first remove an access panel, door or similar obstruction, but a fixture, connection, plumbing appliance, valve, cleanout or equipment is not accessible if access can be…). Removing an access panel is fine.
- Plumbing must accommodate the maximum relative structural movement provided for in the building (OBC Div. B 7.1.3A.1.OBC Div. B 7.1.3A.1. Structural Movement(1) Plumbing shall be designed and installed to accommodate the maximum relative structural movement provided for in the construction of the building.).
- Seismic design of plumbing under Subsection 4.1.8. applies to buildings built under Part 3 (OBC Div. B 7.1.4.1.OBC Div. B 7.1.4.1. Seismic Restraints and Design(1) Plumbing systems in buildings constructed in accordance with Part 3 shall be designed and installed to accommodate the seismic forces addressed in Subsection 4.1.8. (See Note A-7.1.4.1.(1))). A Part 9 house is not caught by this Article, though Part 9 has its own water heater restraint rule (9.31.6.2.(3)).
Worked example
A house sits on a lot where the basement floor is below the sanitary sewer, so gravity drainage to the sanitary system is not possible. Is a basement floor drain required, and where may it go? Sentence 7.1.1B.2.(1) only requires the floor drain where gravity drainage is possible. If the owner still installs one, Sentence (2) lets it drain to the storm system, a dry well or a ditch, but only if it can receive nothing but clear-water waste or storm sewage. A drain next to a laundry tub would not qualify.
Common traps
- Thinking a combined building drain is fine when the street sewer is combined. It is not.
- Giving greywater the rainwater list of uses.
- Applying 7.1.4.1. seismic design to a Part 9 house.
- Treating a fixture behind a screwed access panel as not accessible. It is accessible.
Chapter review
Chapter at a glance
One line per section: the idea to carry into the exam. Then the answers that most often catch candidates out.
- Scope, application and definitions
The scope of Part 7 is set in Div. A Subsection 1.3.3.. Part 7 applies to the design and construction of plumbing.
- Plumbing facilities
Required facilities come from Subsection 3.7.4. and Section 9.31.. For a house that means a kitchen sink, lavatory, water closet and bathtub or shower.
- Service connections
A combined building drain or combined building sewer must not be installed.
Usual exam traps
- Thinking a combined building drain is fine when the street sewer is combined. It is not.
- Giving greywater the rainwater list of uses.
- Applying 7.1.4.1. seismic design to a Part 9 house.
- Treating a fixture behind a screwed access panel as not accessible. It is accessible.
Practice this chapter
Questions on Part 7 general: scope, definitions, facilities and service connections, in the exam format, every answer explained and cited to its article. Sign in to start; a free account gets the free questions.
Code cited in this chapter
Based on the official 2024 Building Code Compendium on ontario.ca.
© King's Printer for Ontario, 2024. Reproduced with permission.
OBC Div. B 7.1.0.1. Scope
Open OBC Div. B 7.1.0.1. in the code viewer(1)The scope of this Part shall be as described in Subsection 1.3.3. of Division A.
OBC Div. B 7.1.1.1. Application
Open OBC Div. B 7.1.1.1. in the code viewer(1)Except as provided in Sentence (2), this Part applies to the design and construction of plumbing.
(2)This Part does not apply to industrial process systems unless the industrial process system is interconnected with the plumbing system, in which case the interconnection shall be so designed and installed so that the plumbing system is protected against contamination or malfunction that may be caused by the industrial system.
OBC Div. B 7.1.1A.1. Definitions
Open OBC Div. B 7.1.1A.1. in the code viewer(1)Except as provided in Sentence (2), words that appear in italics are defined in Article 1.4.1.2. of Division A and in the Building Code Act, 1992.
(2)In this Part,
Storey means the interval between two successive floor levels including mezzanine floors that contain plumbing fixtures or between a floor level and roof.
OBC Div. B 7.1.1B.1. Facilities Required
Open OBC Div. B 7.1.1B.1. in the code viewer(1)Plumbing facilities shall be provided in accordance with Subsection 3.7.4. and Section 9.31.
OBC Div. B 7.1.1B.2. Floor Drains
Open OBC Div. B 7.1.1B.2. in the code viewer(1)Where gravity drainage to a sanitary drainage system is possible, a floor drain shall be installed in a basement forming part of a dwelling unit.
(2)Where gravity drainage to a sanitary drainage system is not possible, the floor drain required by Sentence (1) may be connected to a storm drainage system, dry well or drainage ditch provided it is located where it can receive only clear-water waste or storm sewage.
(3)A floor drain shall be provided in a public laundry room, garbage room, incinerator room, boiler or heating room that is not located within a dwelling unit.
OBC Div. B 7.1.2.1. Sanitary Drainage Systems
Open OBC Div. B 7.1.2.1. in the code viewer(1)Except as provided in Section 7.7., sanitary drainage systems shall be connected to a public sanitary sewer, a public combined sewer or a private sewage disposal system.
(2)A combined building drain or a combined building sewer shall not be installed. (See Note A-7.1.2.1.(2))
OBC Div. B 7.1.2.2. Storm Drainage Systems
Open OBC Div. B 7.1.2.2. in the code viewer(1)Except as provided in Section 7.7., storm drainage systems and private sewers conveying storm sewage shall be connected to a public storm sewer, a public combined sewer or a designated storm water disposal location.
OBC Div. B 7.1.2.3. Water Distribution Systems
Open OBC Div. B 7.1.2.3. in the code viewer(1)Except as provided in Section 7.7. and Sentences (2) and (3), water distribution systems shall be connected to a public water main, drinking water system or a potable private water supply system.
(2)Storm sewage or greywater that is free of solids and treated to conform to Article 7.7.4.1. is permitted to be used as a water supply for
(a)water closets,
(b)urinals,
(c)sub-surface irrigation, or
(d)the priming of traps.
(3)Rainwater that is free of solids and treated to conform to Article 7.7.4.1. is permitted to be used as a water supply for
(a)clothes washers,
(b)laundry trays,
(c)mop sinks,
(d)bedpan washers,
(e)water closets,
(f)urinals,
(g)hose bibbs,
(h)sub-surface irrigation, or
(i)the priming of traps.
(4)Piping conveying the non-potable water described in Sentence (2) shall be installed in conformance with Section 7.7.
Show all 14 articles
OBC Div. B 7.1.2.4. Separate Services
Open OBC Div. B 7.1.2.4. in the code viewer(1)Except as provided in Sentences (2) and (3), piping in any building connected to the public services shall be connected separately from piping of any other building, except that an ancillary building on the same property may be served by the same service. (See Note A-7.1.2.4.(1))
(2)No plumbing serving a dwelling unit shall be installed in or under another unit of the building unless the piping is located in a tunnel, pipe corridor, common basement or parking garage, so that the piping is accessible for servicing and maintenance throughout its length without encroachment on any private living space, but this Sentence does not prevent plumbing serving a unit located above another unit from being installed in or under the lower unit.
(3)Water service pipes or building sewers serving buildings located on the same property may connect into a private water supply or a private sewer conforming to Article 7.1.2.5.
OBC Div. B 7.1.3.1. Lighting and Ventilation Requirements
Open OBC Div. B 7.1.3.1. in the code viewer(1)Plumbing fixtures shall not be installed in a room that is not lighted and ventilated in accordance with the appropriate requirements in Parts 3, 6 and 9.
OBC Div. B 7.1.3.2. Accessibility
Open OBC Div. B 7.1.3.2. in the code viewer(1)Every fixture, plumbing appliance, interceptor, cleanout, valve, device or piece of equipment shall be located so that it is readily accessible for use, cleaning and maintenance.
OBC Div. A 1.4.1.2.(1) Accessible
Open OBC Div. A 1.4.1.2.(1) in the code viewerAccessible means, when applied to a fixture, connection, plumbing appliance, valve, cleanout or equipment, to be accessible with or without having to first remove an access panel, door or similar obstruction, but a fixture, connection, plumbing appliance, valve, cleanout or equipment is not accessible if access can be gained only by cutting or breaking materials.
OBC Div. B 7.1.3A.1. Structural Movement
Open OBC Div. B 7.1.3A.1. in the code viewer(1)Plumbing shall be designed and installed to accommodate the maximum relative structural movement provided for in the construction of the building.
OBC Div. B 7.1.4.1. Seismic Restraints and Design
Open OBC Div. B 7.1.4.1. in the code viewer(1)Plumbing systems in buildings constructed in accordance with Part 3 shall be designed and installed to accommodate the seismic forces addressed in Subsection 4.1.8. (See Note A-7.1.4.1.(1))