Skip to content 
Request ServiceBackflow Preventer Installation & Annual Testing — Mississauga
Delex Plumbing installs and tests backflow preventers throughout Mississauga — reduced pressure (RP) assemblies, double check (DC) valves, residential dual checks, and irrigation zone backflow devices. Licensed, certified testers, City registry compliant.
Why Backflow Prevention Is Required in Mississauga
Backflow occurs when water flows backward through a cross-connection — from a non-potable source back into the potable water supply. This can happen when a pressure drop in the municipal main causes water to be drawn backward from a connected system: an irrigation system that has drawn fertilizer or pesticide into the supply line, a fire suppression system, a commercial process connection, or even a garden hose submerged in a bucket of soapy water.
The City of Mississauga and Peel Region require backflow preventers on all cross-connections to the potable water supply. The specific type of backflow preventer required depends on the degree of hazard at the cross-connection. High-hazard connections — irrigation systems with chemical injectors, commercial boiler systems, cooling towers, medical equipment — require a reduced pressure (RP) assembly. Lower-hazard connections may require a double check (DC) valve assembly. Residential hose bibs require at minimum a hose bib vacuum breaker.
Annual testing of certified backflow preventers is mandatory in Mississauga. The test confirms that the differential pressure relief valve in an RP assembly opens at the correct pressure differential and that the check valves seat correctly under test pressure. Failed annual tests must be reported to Peel Region, and assemblies that fail testing must be repaired or replaced within a specified period.
We are certified backflow preventer testers recognized by the American Backflow Prevention Association (ABPA). After testing, we submit the test report directly to the Peel Region backflow prevention registry on your behalf. Properties that miss their annual test receive a notice of non-compliance from Peel Region — we track annual test dates for all clients and provide advance reminders.
Reduced Pressure (RP) Assembly — Installation & Testing
An RP assembly contains two independently acting check valves and a differential pressure relief valve between them. If either check valve leaks, the relief valve opens and discharges water — visibly — rather than allowing backflow to reach the potable supply. This self-indicating feature makes RP assemblies the required device for high-hazard cross-connections in Mississauga commercial and industrial properties.
RP assembly installation requires isolation valves upstream and downstream, test cocks at each check valve and at the relief valve zone, and a minimum 300mm of clearance below the relief valve discharge port to allow observation of any discharge. The assembly must be installed horizontally and protected from freezing — in outdoor installations, an insulated enclosure is required.
We install RP assemblies for irrigation systems, commercial boiler makeup water connections, commercial dishwasher supply lines, cooling tower makeup, and any other high-hazard cross-connection identified during a cross-connection survey. Irrigation systems with chemical fertilizer injectors are classified as high-hazard connections requiring RP protection in all Peel Region municipalities, including Mississauga.
Annual RP testing is performed with a calibrated differential pressure test kit following the ABPA test procedure. The test verifies: check valve 1 is tight (no leakage), check valve 2 is tight, the relief valve opens at a minimum differential pressure of 2 PSI, and the relief valve closes completely. We also inspect the assembly body, test cocks, and isolation valves for corrosion or mechanical damage during each annual test visit.
Residential Backflow Prevention — Hose Bibs & Dual Checks
Peel Region requires hose bib vacuum breakers on all outdoor faucets connected to the municipal supply in Mississauga. A standard outdoor hose bib without a vacuum breaker allows backflow through the hose connection when supply pressure drops — a common scenario during water main flushing or breaks in the distribution system. A hose submerged in a swimming pool, a bucket of herbicide, or a pressure washer reservoir is a direct cross-connection when the tap is open.
Hose bib vacuum breakers are simple, inexpensive devices that thread onto the hose bib nozzle. They allow forward flow and vent to atmosphere when supply pressure drops, preventing back-siphonage. We install vacuum breakers on all outdoor hose bibs as standard practice during any exterior plumbing service visit.
Residential dual check valve assemblies are required on irrigation system connections in many Mississauga properties. Unlike RP assemblies, dual checks do not have a relief valve and are rated for lower-hazard cross-connections. They are non-testable units — when they fail, they are replaced rather than repaired.
For properties with an in-ground irrigation system, the backwater valve and the irrigation system backflow preventer serve different functions and must both be correctly installed. We review the complete cross-connection inventory for each property during a backflow survey and specify the correct device type and test frequency for each connection.
Backflow Preventer Repair & Replacement
When an RP or DC assembly fails its annual test, repair is often possible without replacing the entire assembly. Internal check valve seats and disc assemblies are available as repair kits for most standard assembly brands. A check valve that fails the closure test can be repaired by replacing the seat and disc assembly — a 30-minute procedure that restores the assembly to compliance without the cost of a new assembly.
We repair RP and DC assemblies from Watts, Febco, Ames, and Wilkins — the most common brands in Mississauga commercial and residential installations. For assemblies that are corroded, cracked, or obsolete (no longer supported with repair parts), we replace the assembly with a currently approved model and register the new device with the Peel Region emergency plumbing compliance registry.
For properties where backflow prevention devices were required by the City of Mississauga following a cross-connection survey notice, we coordinate the installation, initial test, and registry submission within the City-specified compliance deadline. We provide written documentation of the installed device, test results, and registry confirmation for your records. The City of Mississauga cross-connection control program identifies unprotected cross-connections through periodic site inspections and issues compliance notices requiring installation within a set deadline. Missing the compliance deadline can result in water service interruption. We have helped dozens of Mississauga commercial and residential property owners achieve compliance quickly — from initial site assessment through device installation, certification testing, and registry reporting — in a single coordinated service process. All devices we install are from the current Peel Region approved product list, ensuring the installation is accepted without issue. Backflow incidents in Mississauga are more common than most homeowners realize. Peel Region reports backflow-related contamination events to the Ontario Ministry of Environment annually — the majority are caused by unprotected irrigation system connections and garden hose cross-connections at properties without vacuum breakers. A correctly installed and annually tested backflow prevention device protects both the individual property and the shared municipal supply that neighbouring properties also use. The integrity of the Peel Region distribution system depends on every cross-connection being protected — a single unprotected connection can contaminate multiple city blocks of supply during a pressure transient event. Calling Delex before a compliance notice arrives is always less costly than responding under a deadline. We offer voluntary cross-connection surveys for Mississauga commercial properties — a site walk-through identifying all existing and potential cross-connections with a written report and device recommendation for each. The survey cost is credited toward any installation work performed within 30 days. A cross-connection survey takes approximately one hour on a standard commercial property and produces a written list of every identified hazard with a recommended device type and estimated installation cost for each.
Free Estimate — Call 416-910-2550
For backflow preventer installation, annual testing, or repair, call 416-910-2550, contact us online, or request service for same-day booking.
Frequently Asked Questions
Q: How much does backflow preventer installation cost in Mississauga?
A: A residential hose bib vacuum breaker costs $80 to $150 installed. A residential dual check assembly costs $250 to $450. A commercial RP assembly installation costs $600 to $1,500 depending on pipe size and enclosure requirements. Annual testing costs $150 to $300. Call 416-910-2550 for a free estimate.
Q: How often must a backflow preventer be tested in Mississauga?
A: Peel Region requires annual testing of all certified RP and DC assemblies in Mississauga. The test must be performed by a certified tester and the results submitted to the Peel Region registry. We handle all testing and reporting on your behalf and track your annual test date.
Q: What happens if my backflow preventer fails the annual test?
A: A failed test result must be reported to Peel Region. The assembly must be repaired or replaced and re-tested within the compliance deadline set by the Region. We handle failed test repair and re-test in a single service call where possible, using manufacturer-approved repair kits.
Q: Do I need a backflow preventer for my irrigation system in Mississauga?
A: Yes. Any irrigation system connected to the Peel Region municipal water supply requires a backflow preventer. The device type depends on whether the system has chemical injectors — if so, an RP assembly is required. If not, a dual check or pressure vacuum breaker is typically acceptable. We specify the correct device during the irrigation connection service.
Get Your Free Estimate Today!
Or Give Us A Call: 416-910-2550
Licensed & Insured
Trusted Local Plumbers 
Fast Response
Usually Within 1 Hour 
Satisfaction Guaranteed
100% Quality Work 