Water Distribution System


1.1.3.2.

Water distribution system means an assembly of pipes, fittings, valves and appurtenances that conveys water from the water service pipe or private water supply system to water supply outlets, fixtures, plumbing appliances and devices.


1.1.3.2.

Water service pipe means a pipe on the property that conveys potable water from a water works or private water source to the inside of the building.




Water distribution systems must connect to one of two different water supply locations. These are either a public water main or if a main is not available, to private potable water system.


7.1.6.3.

  1. Except as provided in Sentence (2), every water distribution system shall be connected to a public water main or if no public water main is available to a potable private water supply system.
  2. Where a supply of potable water is unavailable or insufficient to supply water to a plumbing system, non-potable water may be used for flushing of water closets, urinals or the priming of traps, and the piping conveying the non-potable water shall be installed in conformance with Section 7.7.


There must be no interconnection between the potable and non-potable water systems.

7.7.1.1.(1)

A non-potable water piping shall not be connected to a potable water system.


7.7.3.1.(1)

Non-potable water piping shall not be located


7.7.3.2.(1)

An outlet from a non-potable water system shall not be located where it can discharge into

  • a sink or lavatory,
  • a fixture into which an outlet from a potable water system is discharged,
  • a fixture that is used for a purpose related to the preparation, handling or dispersing of food, drink or products that are intended for human consumption.


7.7.2.1.(1)

Non-potable water piping shall be identified by markings that are permanent, distinct and easily recognized.



7.6.1.1.

  1. Potable water systems must be designed, fabricated and installed in accordance with good engineering practice.
  2. Every fixture supplied with separate hot and cold water controls shall have the hot water control on the left and cold on the right.
  3. Where hot and cold water are mixed and the temperature is regulated by a single, unmarked, manual control, a movement to the left shall increase the temperature and a movement to the right shall decrease the temperature.



7.6.1.2.(1)

A water distribution system shall be installed so that the system can be drained or blown out with air and outlets for this purpose shall be provided.


In normal circumstances, the distribution system will drained down through the lowest faucets on the system, as in the laundry tub faucet.


7.6.2.2.(1)

Every newly installed part of a potable water system shall be cleaned and free of any matter that may affect the health of a person before being put into service (See Appendix A.) (with chemicals)


The minimum diameter of a water distribution system is 3/4" from the connection of the water service pipe to the branch that supplies the hot water tank.

7.6.3.2.(2)

No water system between the point of connection with the water service pipe or the water meter and the first branch that supplies a water heater, shall be less than 3/4" size.


The minimum water service size is 3/4".

7.6.3.4.(1)

Every water service pipe shall be not less than 3/4" trade size.




The minimum water pipe size that may be installed to serve a number of common fixtures is listed in Table 7.6.3.1.. Most of the common fixtures listed in the table require a 1/2" supply with a few having a minimum of 3/8" and one fixture, a direct flush valve water closet requiring a minimum pipe size of 1".

7.6.3.1.(1)

Except as provided in Sentence (2), the size of every water distribution system that supplies water to a fixture or device shall comply with Table 7.6.3.1..


We are permitted to use the supply tube instead of prescribed pipes as long as the length of 3/8" tube is not more than 14"

7.6.3.1.(2)

Where a pipe in a water distribution system is not directly connected to a fixture or a fixture faucet but is connected with a flexible tube of a diameter smaller than that specified by Table 7.6.3.1., the developed length of the connector shall not be more than 355 mm (14"0 and, where 3/8" pipe of iron pipe size is used, the maximum length shall not exceed 914 mm (3').



7.6.3.3.(1)

Where the static water pressure exceeds 550 kPa (79.8 psi), a pressure reducing valve shall be installed to limit the maximum static pressure to not more than 550 kPa (79.8 psi) in areas that may be occupied.


7.2.10.12.(1)

Direct acting water pressure reducing valves for domestic water supply systems shall conform to CSA-B356, Water Reducing Valves for Domestic Water Supply Systems".


7.2.1.3.(2)

Materials and equipment that have been used for a purpose other than the distribution of potable water shall not be subsequently used in a potable water system.


7.6.2.1.

  1. Connections to potable water systems shall be designed and installed so that non-potable system water or substances that may render the non-potable cannot enter the system.
  2. No connection shall be made between a potable water system supplied with water from a drinking-water system and any other potable water system without the consent of the water purveyor.


7.6.2.3. Back Siphonage

  1. Every potable water system that supplies a fixture or tank that is not subject to pressure above atmospheric shall be protected against back-siphonage by a backflow preventer.
  2. Where a potable water supply is connected to a boiler, tank, cooling jacket, lawn sprinkler system or other device where a non-potable fluid may be under pressure that is above atmospheric or the water outlet may be submerged in the non-potable fluid, the water supply shall be protected against backflow by a backflow preventer.
  3. Where a hose bibb is installed outside a building, inside a garage, or where there is an identifiable risk of contamination, the potable water system shall be protected against backflow by a backflow preventer.
  4. Where a potable water system system serves a fire protection system, the fire protection system shall be isolated from potable water system in the following manner:
  1. a wet sprinkler fire protection system containing water only shall be provided with a listed alarm check valve installed in conformance with NFPA 13, "Installation of Sprinkler Systems".
  2. a wet standpipe fire protection containing water only shall be provided with a resilient seated check valve.
  3. a wet sprinkler or wet stand pipe fire protection system containing anti-freeze or chemicals shall be provided with a reduced pressure principle backflow preventer certified to CAN/CSA-B64.4 Series, "Backflow Preventers, Reduced Pressure Principle Type (RP)".
  4. a dry sprinkler or dry stand pipe fire protection system does not require isolation.
  5. a water storage tank fire protection system shall be provided with a backflow preventer certified to CAN/CSA-B64.4 Series, "Backflow Preventers and Vacuum Breakers".
  6. A fire hydrant fire protection fire protection system does not require isolation.
  7. a fire service main shall be provided with a reduced pressure principle backflow preventer certified to CAN/CSA-B64.4, "Backflow Preventers, Reduced Pressure Principle Type (RP)" if it is connected to more than one of the following different sources of supply:

i) a drinking water system, or

ii) a source of non-potable water.

  1. Backflow prevention devices shall be provided in conformance with Sentence 7.2.10.10(1).-link neitralizing_dilution_tanks


  1. Building of residential occupancy within the scope of Part 9 are not require to be isolated unless they have access to an auxiliary water supply.