Code: RPZ (Backflow prevention device)
Description: (Reduced Pressure Zone Backflow Preventer) is a mechanical device installed on a water supply line to prevent contaminated water from flowing backward into the clean city water supply, used where there is a higher risk of contamination than a standard PVB or DCVA can handle. It is required by NYC DEP in situations involving higher hazard levels, such as buildings with boilers, chemical systems, or other equipment that could seriously contaminate the public water supply if backflow occurred.
Practical Meaning: For a NYC homeowner or building owner, an RPZ device may be required by DEP if your property has a system that poses a high contamination risk to the water supply — such as a boiler, irrigation system, or fire suppression system with chemicals. You must have the RPZ installed by a licensed plumber, tested annually by a certified tester, and the test results filed with DEP — failure to do so can result in DEP violations and water service interruption.
Where You May See It: DEP backflow prevention notice, DEP filing requirements, plumbing plans, building compliance review, contractor or expeditor proposal, annual backflow test report, DOB violation referencing cross-connection control.
Why It Matters: Missing or untested RPZ devices can lead to DEP violations, mandatory water service shut-off, and serious liability if contamination occurs. Owners who ignore annual DEP testing and reporting often discover the problem only when they try to sell or refinance and a compliance review reveals open DEP issues.