Backflow Prevention: Why It Matters and What NVC Requires
Backflow prevention isn't glamorous, but it's one of the most important protections in your plumbing system. Here's what it is, why NVC requires it, and what you need to know.
What Is Backflow?
Backflow happens when water flows backward through your plumbing — from your property back into the public water supply. This can happen due to a pressure drop in the city main (a broken water main, fire hydrant use, etc.) or from excessive pressure in your system. When it happens, contaminated water can enter the clean water supply.
Why It's Dangerous
Backflow can push chemicals, bacteria, fertilizer, or wastewater into the drinking water supply. A single backflow event from one property can contaminate water for an entire block. This is why NVC requires backflow prevention on all commercial properties and many residential connections.
- Irrigation systems with fertilizer
- Boiler systems with chemical treatment
- Commercial kitchens and food processing
- Dental and medical offices
- Swimming pools and spas
NVC Requirements
NVC code requires backflow prevention assemblies (BPAs) on all commercial water service connections and on residential properties with irrigation systems, pools, or solar heating. BPAs must be tested annually by a certified tester and results must be filed with the NVC Water Authority.
Types of Backflow Preventers
The most common types in NVC are reduced pressure zone (RPZ) assemblies for high-hazard connections and double check valve assemblies (DCVA) for low-hazard connections. Your plumber will determine which type you need based on your specific installation.
- RPZ: Required for commercial kitchens, chemical connections, fire sprinklers
- DCVA: Suitable for irrigation, pools, low-hazard residential
- Atmospheric vacuum breakers: For individual fixtures like hose bibs
Annual Testing
NVC requires annual testing of all backflow prevention assemblies. The test takes about 30 minutes and must be performed by a certified tester. Marco is certified and files results directly with the NVC Water Authority. If your BPA fails the test, it usually means a repair or replacement of internal check valves — a routine service.
Need your backflow preventer tested? Marco is a certified backflow tester. Call 555-0714 to schedule your annual test.