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Section 7.1. is short, but it decides the big questions for every plumbing permit: does Part 7 apply at all, where must each system connect, can two buildings share a service, and when does seismic design reach the plumbing. On the All Buildings exam the same Articles that a house designer knows show up in larger settings: a plant with process piping, a campus of buildings on one property, an apartment building with stacked units, or a Part 3 hospital in a seismic zone.
Scope, application and definitions
The scope of Part 7 is whatever Div. A Subsection 1.3.3. says it is (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 then 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…), with one carve-out: an industrial process system is outside Part 7. The carve-out ends where the process system is interconnected with the plumbing system. At that point the interconnection must be designed so that the plumbing system is protected against contamination or malfunction caused by the industrial system. So a factory's chemical rinse loop is not plumbing, but the potable water connection that feeds it is, and that connection must be protected.
Italic terms take their meaning from Div. A 1.4.1.2. and from the Building Code Act. Part 7 adds its own meaning of storey (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…): the interval between two successive floor levels, counting a mezzanine floor only if it contains plumbing fixtures, or between a floor level and the roof. In a tall building this changes storey counts for stack and vent rules. A mezzanine with a washroom is a storey for Part 7; an open mezzanine with no fixtures is not.
Definitions that matter in this section:
| Term | What it means in short | Source |
|---|---|---|
| Accessible | reachable with or without removing a panel or door; not accessible if you must cut or break material | 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… |
| Private water supply | piping on the property that is the source for more than one water service pipe | def.OBC Div. A 1.4.1.2.(1) Private water supplyPrivate water supply means piping that serves as a source of supply on the property to more than one water service pipe. |
| Water service pipe | pipe on the property carrying potable water from a drinking water system or private water supply into the building | def.OBC Div. A 1.4.1.2.(1) Water service pipeWater service pipe means a pipe on the property that conveys potable water from a drinking water system or a private water supply to the inside of the building. |
| Building sewer | pipe joined to the building drain 1 m outside a wall, leading to a public sewer or private sewage disposal system | def.OBC Div. A 1.4.1.2.(1) Building sewerBuilding sewer means a pipe that is connected to a building drain 1 m outside a wall of a building and that leads to a public sewer or private sewage disposal system. |
| Sewer lateral extension | the part of a building sewer from the public sewer up to 1.5 m into the property | def.OBC Div. A 1.4.1.2.(1) Sewer lateral extensionSewer lateral extension means the portion of a storm building sewer or sanitary building sewer that extends from the public sewer up to 1.5 m into the property. |
Plumbing facilities
Part 7 does not itself count fixtures. It points to Subsection 3.7.4. and Section 9.31. for the required facilities (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 an office, school or restaurant you go to the Part 3 fixture tables (covered in the PAB-2 chapter).
Floor drains (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…):
| Location | Rule |
|---|---|
| Basement forming part of a dwelling unit, gravity drainage to the sanitary system possible | floor drain required |
| Same basement, gravity drainage not possible | the drain may go to a storm system, dry well or ditch if it can receive only clear-water waste or storm sewage |
| Public laundry room, garbage room, incinerator room, boiler or heating room not within a dwelling unit | floor drain required |
The third row is the one that catches larger buildings: the common laundry room of an apartment building, its garbage room and its boiler room each need a floor drain.
Service connections
| System | Must connect to | Article |
|---|---|---|
| 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, and private sewers carrying storm sewage | 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 system | 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… |
Each of these starts with "except as provided in Section 7.7.", which is the door to rainwater harvesting and re-use systems. A combined building drain or combined building sewer must not be installed, whatever the street sewer is (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))).
Non-potable water may serve some outlets if it is free of solids and treated to 7.7.4.1. (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…):
| Use | Storm sewage or greywater | Rainwater |
|---|---|---|
| Water closets, urinals | yes | yes |
| Sub-surface irrigation, trap priming | yes | yes |
| Clothes washers, laundry trays, mop sinks | no | yes |
| Bedpan washers, hose bibbs | no | yes |
A hospital asking to supply bedpan washers from treated rainwater is fine under this Sentence; supplying them from greywater is not.
Separate services and multi-building sites
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…). Two exceptions, and one related restriction:
- An ancillary building on the same property may share the main building's service.
- Buildings on the same property may connect their water service pipes or building sewers into a private water supply or private sewer that meets 7.1.2.5. (7.1.2.4.(3)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…). This is how a campus, plaza or townhouse block with its own internal mains is served.
- Restriction: within one building, plumbing serving a dwelling unit may not run in or under another unit unless it is in a tunnel, pipe corridor, common basement or parking garage, accessible along its length without entering private living space. Piping for an upper unit may still pass through or under the unit below (7.1.2.4.(2)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…).
Private water supply pipes follow the MOE guideline PIBS 6881e, "Design Guidelines for Drinking-Water Systems", and private sewers follow PIBS 6879, "Design Guidelines for Sewage Works" (OBC Div. B 7.1.2.5.OBC Div. B 7.1.2.5. Private Sewers and Private Water Supply(1) Private water supply pipes shall be designed and installed according to MOE PIBS 6881e, "Design Guidelines for Drinking-Water Systems". (2) Private sewers shall be designed and installed according to MOE PIBS 6879, "Design Guidelines for Sewage Works".). Note the pairing: water uses 6881e, sewers use 6879.
Location of fixtures, movement and seismic design
- A fixture may not be installed in a room that is not lighted and ventilated to 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.). A grease interceptor buried under a fixed kitchen floor with no access cover fails this rule.
- 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.). Think of stacks crossing expansion joints or long risers in a high building.
- Plumbing in buildings constructed under Part 3 must be designed and installed for the seismic forces of Subsection 4.1.8. (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))). This is where PAB differs most from the house exam: a Part 3 building brings seismic restraint of plumbing; a Part 9 building does not trigger this Article.
Worked example
A developer builds three retail buildings on one property with one connection to the municipal water main and one to the sanitary sewer. Inside the property a private water main and private sewer branch to each building. Is this allowed?
- Start with 7.1.2.4.(1): each building normally has a separate connection.
- Sentence (3) permits water service pipes and building sewers of buildings on the same property to connect into a private water supply and a private sewer.
- Those private systems must meet 7.1.2.5.: the water side to PIBS 6881e, the sewer side to PIBS 6879.
Answer: yes, provided the private systems are designed to those two guidelines.
Common traps
- Assuming Part 7 governs an industrial process loop. It does not, but the interconnection with plumbing must protect the plumbing system.
- Forgetting the floor drain in a common laundry, garbage or boiler room of an apartment building.
- Swapping the two MOE guidelines (6881e is water, 6879 is sewage).
- Applying 7.1.4.1. seismic design to a Part 9 building, or forgetting it for a Part 3 building.
- Giving greywater the longer rainwater list of uses.
- Thinking a combined street sewer allows a combined building drain.
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 whatever Div. A Subsection 1.3.3. says it is.
- Plumbing facilities
Part 7 does not itself count fixtures.
- Service connections
Each of these starts with "except as provided in Section 7.7.", which is the door to rainwater harvesting and re-use systems.
Usual exam traps
- Assuming Part 7 governs an industrial process loop. It does not, but the interconnection with plumbing must protect the plumbing system.
- Forgetting the floor drain in a common laundry, garbage or boiler room of an apartment building.
- Swapping the two MOE guidelines (6881e is water, 6879 is sewage).
- Applying 7.1.4.1. seismic design to a Part 9 building, or forgetting it for a Part 3 building.
- Giving greywater the longer rainwater list of uses.
- Thinking a combined street sewer allows a combined building drain.
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. 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. A 1.4.1.2.(1) Private water supply
Open OBC Div. A 1.4.1.2.(1) in the code viewerPrivate water supply means piping that serves as a source of supply on the property to more than one water service pipe.
OBC Div. A 1.4.1.2.(1) Water service pipe
Open OBC Div. A 1.4.1.2.(1) in the code viewerWater service pipe means a pipe on the property that conveys potable water from a drinking water system or a private water supply to the inside of the building.
OBC Div. A 1.4.1.2.(1) Building sewer
Open OBC Div. A 1.4.1.2.(1) in the code viewerBuilding sewer means a pipe that is connected to a building drain 1 m outside a wall of a building and that leads to a public sewer or private sewage disposal system.
OBC Div. A 1.4.1.2.(1) Sewer lateral extension
Open OBC Div. A 1.4.1.2.(1) in the code viewerSewer lateral extension means the portion of a storm building sewer or sanitary building sewer that extends from the public sewer up to 1.5 m into the property.
Show all 19 articles
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.
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 7.1.2.5. Private Sewers and Private Water Supply
Open OBC Div. B 7.1.2.5. in the code viewer(1)Private water supply pipes shall be designed and installed according to MOE PIBS 6881e, "Design Guidelines for Drinking-Water Systems".
(2)Private sewers shall be designed and installed according to MOE PIBS 6879, "Design Guidelines for Sewage Works".
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. 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))