Safety Codes Bulletin: Sump Pumps within Dwelling Units

2023-08-16

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Purpose

This bulletin is issued to rescind the previously established guidelines concerning the recommendation of sump pits within dwelling units.

Discussion

In November 2011, the City of Medicine Hat released a Safety Codes Bulletin outlining guidelines for the installation of sump pits within dwelling units. These guidelines aimed to inform stakeholders about the requirements outlined in the Building, Plumbing, and Electrical construction codes for cases involving the installation of sump pits. Originally, these guidelines were developed primarily for parcels within the Southlands subdivision that were identified as having potential high groundwater levels.

Interpretation

Effective immediately, the installation of a sump pit will not be mandatory for new buildings containing one or two dwelling units, provided that the excavation does not indicate any signs of potential water ingress and foundation drains (also known as weeping tile) can be naturally drained to a sewer by gravity.

However, if it is determined that gravity drainage is not feasible for the foundation drainage (weeping tile), a sump pit will still be required. This situation typically arises in walkout foundations where foundation footings step down to ensure proper frost coverage in areas where the basement floor aligns with the ground level.

In cases where an excavation reveals a potential high-water table, additional drainage might be necessary. Granular drainage layers connected with drainage piping must be drained to storm or sanitary sewers by gravity, or if deemed necessary, through a sump pit.

When installing a sump pit, it is crucial to adhere to the guidelines of the 2020 National Plumbing Code and install a sump pump. The sump pump must be equipped with a dedicated branch circuit and an outlet that is permanently labeled as a sump pump receptacle and placed in proximity to the pump. This dedicated branch circuit should not be equipped with arc-fault protection.

The responsibility for ensuring that design drawings submitted for a building permit application align with the Safety Codes Act and its regulations falls on the building designer. If a sump pit is installed, construction drawings must include detailed information.

Code References for Sump Pits and Pumps

2019 NBC (AE)

9.14.5.1. Drainage Disposal

1) Foundation drains shall drain to a sewer, drainage ditch or dry well.

9.14.5.2. Sump Pits

1) Where a sump pit is provided it shall be

a) not less than 750 mm deep,

b) not less than 0.25 m2 in area, and

c) provided with a cover.

2) Covers for sump pits shall be designed

a) to resist removal by children, and

b) to be airtight in accordance with Sentence 9.25.3.3.(7).

3) Where gravity drainage is not practical, an automatic sump pump shall be provided to discharge the water from the sump pit described in Sentence (1) into a sewer, drainage ditch or dry well.

2020 NATIONAL PLUMBING CODE

2.4.5.3. Connection of Subsoil Drainage Pipe to a Sanitary Drainage System

1) Where a subsoil drainage pipe is connected to a sanitary drainage system, the connection shall be made on the upstream side of a trap with a cleanout or a trapped sump.

2.4.6.3. Sumps or Tanks

1) Piping that is too low to drain into a building sewer by gravity shall be drained to a sump or receiving tank.

3) Where the sump or tank receives subsurface water from a subsoil drainage pipe, it shall be provided with a water- and air-tight cover.

4) Equipment such as a pump or ejector that can lift the contents of the sump or tank and discharge it into the building drain or building sewer shall be installed.

5) Where the equipment does not operate automatically, the capacity of the sump shall be sufficient to hold at least a 24 h accumulation of liquid.

7) The discharge pipe from every pumped sump shall be equipped with a union, a backwater valve and a shut-off valve installed in that sequence in the direction of discharge.

8) The discharge piping from a pump or ejector shall be sized for optimum flow velocities at pump design conditions.

2021 CANADIAN ELECTRICAL CODE: Part 1

Rule 26-658 Arc-fault protection of branch circuits for dwelling units

Arc-fault protection of branch circuits for dwelling units shall meet the following requirements:

1) Each branch circuit supplying 125 V receptacles rated 20 A or less shall be provided with arc-fault protection by a combination-type arc-fault circuit interrupter, except for branch circuits supplying

b) a single receptacle for a sump pump where

i) the receptacle is labelled in a conspicuous, legible, and permanent manner identifying it as a sump pump receptacle; and

ii) the branch circuit does not supply any other receptacles.

Planning and Development Services
City of Medicine Hat

Unless stated otherwise, the Code references in this Bulletin are to Division B of the current National Building Code – Alberta Edition (NBC-AE) Bulletins do not overrule the NBC-AE nor constitute a relaxation of the Code. They serve to clarify the Code in areas where the latter is ambiguous or does not cover a specific topic. Bulletins are City of Medicine Hat clarifications for staff use to enable consistency in the application of the Code. Regulation Bulletins should always be read in the context of the appropriate requirements of the Code.