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Answers To FAQ

Backflow Prevention FAQs

What is backflow prevention?

The water in our domestic water mains is classified as “potable”, or safe to drink. Once it enters our buildings, it becomes cross-connected via copper piping to plumbing fixtures such as hot water heaters, boilers, washing machines, lawn sprinklers, garden hoses and swimming pools. That’s where the clean water becomes contaminated with rust inhibitors, bleach and chemical surfactants, animal waste, and other contaminants. Under normal conditions, the contaminated water stays where it is and is eventually and safely discharged into our sewers. When water pressure within a NYC building exceeds the water pressure delivered by the water main, the water within the building will reverse direction and pollute our clean, drinking water. The resulting back-siphonage is called ‘backflow’. Backflow prevention devices are designed to prevent back-siphonage as well prevent reverse flow due to back-pressure.

What causes a reduction in supply pressure?

Water main breaks, thermal expansion from hot water boilers/ heaters or an open fire hydrant are main causes for pressure reduction and potential backflow hazards. Drinking water contaminated with “backflow particulates” can be hazardous, making backflow prevention a legal mandate throughout the entire country.

Am I required to have a backflow device installed?

Every building inside the five boroughs of NYC is required to install primary backflow preventers on each water main that feeds the property. If you have a fire/sprinkler system in place, you’ll need to install a primary backflow preventer immediately downstream from the DEP meter or fire/sprinkler supply branch.

*Please be aware that a DEP “Order to install a Backflow Preventer” provides a finite period of time to complete the work before a violation is issued. If you ignore it, the DEP can and will shut the water to your entire building.

What is a primary backflow preventer?

A primary backflow preventer is a plumbing device consisting of two to three internal valves that absolutely prevents the water inside your building from reversing flow and contaminating the local water supply. It’s installed immediately downstream from the DEP water meter. These devices are aggressively managed by NYC DEP’s Cross Connection Control Unit (CCCU) in Flushing, Queens.

What is a secondary backflow preventer?

Secondary backflow devices protect the drinking water in your building from getting contaminated by dangerous, hazardous or objectionable substances that are already inside your building. Secondary devices that protect the buildings’ internal drinking water from contamination are managed by NYC DOB and should be tested annually.

How do I know if I need an RPZ (Reduced Pressure Zone) or DCV (Double Check Valve).

The threat level posed by dangerous, toxic or objectionable substances that exist inside your building will determine which type of backflow device you need. Most buildings require an RPZ on their domestic supply lines and a DCDA (double check detector assembly) or RPDA (reduced pressure zone detector assembly) on the fire/sprinkler supply lines. The DCV is the recommended solution for low hazard conditions and the RPZ is the recommended solution for high hazard conditions, since it has a relief valve that will dump contaminated water down the drain vs. siphoning it out of your building. Your inspector will determine which type of device is required for your property.


How many backflow devices are required per property?

A backflow preventer must be installed on each water supply line, including your domestic, fire/garden sprinkler system.

Testing FAQs

How often does a backflow device need to be tested?

NYC DEP mandates that ALL backflow devices be tested every 12 months by a NYS Certified Backflow Tester who is employed by a NYC Licensed Master Plumber. The test results must be overnighted in the form of annual testing reports (GEN215B’s) to NYC DEP’s Cross Connection Control Unit in Flushing, Queens.

How do I get my backflow device tested?

Contact Ashokan Water Meter and Backflow to schedule an annual inspection of your backflow device. We will also submit the required documentation to the DEP so you will have proof of compliance.

How are annual tests* performed?

Each backflow preventer has four test ports, which are used to connect a pressure kit that has the ability to create backflow pressure in each test port to simulate a real backflow situation. The Certified NYS tester watches the gauges closely to make sure each internal valve opens and closes correctly.


*Please note that the water supply to the entire building must be shut, as there cannot be any downstream demand while we test. When we call to schedule the tests with you, we encourage you to post a brief water shut-off notice in your building so your tenants are aware of the very brief shut down.

My backflow preventer is dripping, what does that indicate?

It’s likely that there’s dirt and debris build-up accumulating internally, which can freeze the moving parts of your device in place, and prevent check valves from opening and closing. When check valves no longer open and close freely, your device may leak slightly. An RPZ can actually dump a very high rate of water from its Relief Valve and when that happens, it’s likely that you may need to clean or replace some of the internal components.

Can I remove a backflow violation?

It is possible to have a violation dismissed and it’s also possible to actually receive a reduced fine, as long as you test and file those tests prior to the initial hearing date. A dismissal can occur when the DEP makes a mistake by issuing a violation, despite the fact that the device had been tested.

Am I required to test downline devices?

Yes, you are required to test secondary backflow preventers. DOB(Department of Buildings) is the controlling authority for downline devices and they send inspectors out for physical inspections of buildings. When the inspector arrives, he/she may ask for your completed annual test reports and if you do not have them, they will issue an IWN.