FAQ
Do Car Washes Need Backflow Preventers in New Jersey?
Car wash facilities use large volumes of water with high concentrations of cleaning chemicals, create significant back-pressure from high-pressure wash equipment, and often recycle wash water — making them one of the highest-risk commercial backflow environments in any community. In New Jersey, car washes are required to have RPZ assemblies and other backflow prevention devices on their water supply connections. This guide explains the specific requirements.
For the full picture of device types and hazard classifications, see our guide to types of backflow preventer valves and warning signs.
Why Car Washes Are High-Hazard Cross-Connection Sites
Chemical detergents and wax compounds: Car wash chemicals are formulated with high concentrations of surfactants, alkalis, and wax emulsions. Back-pressure from high-pressure pump systems could push these chemicals into the potable supply without adequate backflow protection
Reclaimed water systems: Most modern car washes recirculate and treat a portion of their wash water. Any connection between the reclaimed water system and the potable water supply is a high-hazard cross-connection
High-pressure equipment: Pump systems generating 1,000–3,000 PSI easily exceed typical municipal supply pressure. Back-pressure from these systems against an inadequate backflow device is a very real risk
Rinse aids and drying agents: Specialty chemicals used in the final rinse stages are toxic at the concentrations used
What Devices Are Required at a New Jersey Car Wash?
Main Water Service Connection: RPZ Required
All New Jersey water authorities require RPZ assemblies on the main water service connection for car wash facilities. The RPZ provides service protection against any backflow from the facility’s entire plumbing system into the public supply.
Reclaimed Water Connections: RPZ Required
Any connection between the reclaimed water system and the potable water supply — including makeup water connections that top off the reclaimed water tank — requires an RPZ assembly. The reclaimed water is classified as a high-health-hazard source because it contains the accumulated chemical load from multiple wash cycles and biological contamination from vehicle surfaces.
Chemical Injection Systems: RPZ Required
Chemical proportioning systems that inject detergents, degreasers, and wax compounds into the wash water require RPZ protection at the water supply connection. The chemical injection creates a high-health-hazard cross-connection requiring maximum protection.
Annual Testing Requirements for Car Wash Backflow Devices
Like all backflow prevention devices in New Jersey, car wash RPZ assemblies must be tested and certified annually. Car wash facilities typically have multiple testable devices — service protection RPZ, chemical system RPZs, reclaimed water connection RPZs — each requiring its own annual test. South Jersey Backflow provides multi-device annual testing for car wash facilities throughout all of New Jersey, with all test reports filed directly with the appropriate water authority. See our backflow preventer installation, testing, and rebuilding costs for commercial testing pricing. contact South Jersey Backflow.
Schedule Your Backflow Service Anywhere in New Jersey
South Jersey Backflow has proudly served residential and commercial customers across all of New Jersey since 2004. Our certified technicians provide annual backflow testing and certification, expert repairs and rebuilds, and protective backflow enclosures — all with transparent pricing, complete paperwork handling, and 24/7 emergency availability. Call (856) 291-6809 or contact us online to get started today.