Region of Durham backflow prevention program (By-law 24-2018)

Who has to comply

On June 13, 2018, Durham Regional Council passed Backflow Prevention By-law 24-2018 as part of the Region's multi-barrier approach to safe drinking water. The by-law requires a premise-isolation backflow preventer, tested and maintained every year, on every water service that could pose a hazard to the municipal system. It applies to industrial, commercial, institutional and multi-residential properties classified as severe or moderate hazards under the CSA B64 series of standards, wherever Regional water is supplied. Multi-residential means an apartment, condominium, townhouse, co-op or similar property with more than six self-contained dwelling units. The by-law also applies to any property where a condition hazardous to the drinking water system exists.

Council amended the by-law on May 27, 2026 (By-law 2026-023). The amendment:

• makes the owner responsible for the 5-year survey and the annual test;
• makes the tester responsible for filing every test report within 28 days;
• requires every tester to be registered with the Region before carrying out any authorized function (survey, installation, repair or test) under the by-law;
• makes fines recoverable under the Provincial Offences Act.

The hazard classification decides the device. A severe hazard needs a reduced-pressure assembly (RP, also called an RPZ). A moderate hazard needs a double check valve assembly (DCVA).

The steps Durham sets out

1. Survey notice. The Region notifies the property owner that a cross-connection survey is required. The Region issued its survey report notices on October 1, 2019.
2. Survey. A qualified contractor surveys the property and submits the survey online through BSI's website within 90 days of the notice. The survey identifies connections to the drinking water system and any on-site hazards. Anything severe or moderate requires a device.
3. Region's notice. Based on the survey, the Region issues a notice to install, repair or test a device. The owner has 180 days from the notice to complete the work.
4. Installation, testing and reporting. The contractor applies to the local building department for permits, installs what is required and tests it to the CSA B64 series. The test report goes through BSI within 28 days of the test. The by-law requires each survey and test report to go to both the Region and the local municipality; we file through BSI and send the local municipality its copy. If a device fails, the tester notifies the Region and the local municipality in writing within 24 hours, and the device is repaired or replaced immediately at the owner's expense. Every device is then tested and maintained annually. The owner keeps the test reports on site for at least 5 years.
5. Repeat surveys. A new survey is required every 5 years from the first requested survey. It is required sooner after a change of tenant, ownership, zoning, facility use or chemical use, or when the Commissioner of Works requires it.

Fees

There is no fee to submit a survey report or to register as a tester. The Region charges $26.00 for each test report under its 2026 fee schedule, paid online at the time of submission (the Region's program page still shows the earlier $25).

Who is a qualified contractor

Durham defines a qualified contractor as a person certified by the Ontario Water Works Association, or another body the Region approves. The Region's definition covers installation, testing and maintenance; the by-law's Authorized Functions List adds the cross-connection survey. Every tester must register with the Region each year and provide proof of certification. Since the 2026 amendment, no one may carry out an authorized function under the by-law unless registered. The Region's qualified contractor list, kept by BSI, shows the company under its former name, Spec-Mark Mechanical. Our certificates are listed on the Qualifications page.

What we do in Durham

For a property in Durham we:

• complete the survey the Region's notice asks for and submit it through BSI;
• apply for permits and install devices where the Region requires them;
• test every device annually;
• submit each test report through BSI, with a copy to the local municipality and to you;
• pay the report fee on your behalf.

We keep the next due date on file and send a courtesy reminder before it; the due date remains the owner's responsibility.

Permits from the local municipality

The Region runs the program and receives every report. Devices beyond premise isolation are the responsibility of the local building department. The building permit for any new device comes from the city or town.

Permit rules by municipality: Oshawa, Pickering, Whitby, Ajax, Clarington, and Uxbridge, Scugog and Brock.

Ajax

Ajax properties on the Regional water system follow the same by-law, deadlines and BSI filing route. Plumbing permit applications to the Town of Ajax go through its online application portal for residential properties. For everything else they go by email to the Town's building permits address. Staff pre-screen the submission. The date of application is the day after the pre-screen is approved. The Town's 2026 fee schedule has no line for plumbing or backflow work. The fee is therefore 1.5 per cent of the estimated construction value, or an amount the Chief Building Official determines. A $44 pre-application review fee is paid first and credited to the permit fee. Plumbing inspections, from outside service to final, are booked on the Town's inspection line with a day's notice. We found no backflow-specific checklist on the Town's website.

Clarington

Clarington properties on the Regional water system, including Bowmanville, Courtice, Newcastle, Newtonville and Orono, follow the same program. The Municipality of Clarington requires a permit for altering or adding any plumbing. The permit is applied for through its Service Clarington portal. Plumbers working on a Clarington permit must hold a municipal plumbing licence under By-law 89-175; in Clarington, installation is done by a plumber licensed by the Municipality. Under Building By-law 2024-006, consolidated in January 2026, the fee is $54.45 for each backflow preventer. The minimum fee is $135.31. Fees rise by 3 per cent each January. Inspections are requested by 3 p.m. the business day before. A plumbing inspector witnesses the tests the Building Code requires. The Building Division is on the main floor of the Municipal Administrative Centre at 40 Temperance Street in Bowmanville.

Uxbridge, Scugog and Brock

The three northern townships are covered by the by-law wherever Regional water is supplied. The same survey, testing and BSI reporting rules apply. Permits come from each township's building department.

Backwater valves across Durham

A backwater valve is a sewer device that stops sewage from backing up into a basement. It is not what the Region's backflow notice is about.

Homeowners may be eligible for help under the Region's basement flooding programs; the Region sets the terms, and the local building permit applies.