Backflow Prevention

Federal and State law requires that water suppliers protect their water systems from contamination. When a determination is made by the City that the potable (drinking) water system may be subject to contamination through a backflow condition, the customer will be notified and required to install an approved backflow prevention assembly. The City makes these decisions based on a case-by-case basis. Residential, commercial and industrial customers demonstrating a high potential for contaminants to enter the potable water system must install and maintain backflow prevention assemblies. The Sate Water Resources Control Board-Division of Drinking Water (SWRCB-DDW) requires each of these assemblies to be tested annually. This testing is done by backflow assembly testers approved by the County of Los Angeles Public Health -Cross Connections & Water Pollution Control.  Failure to have the device(s) tested could result in the termination of water service.

The City of Inglewood Water Department (City) is committed to delivering safe, high quality water to customers. Our water quality program operates 24 hours a day, 365 days a year, to ensure that the water delivered to our customers is kept free from harmful contaminants. City had adopted Inglewood Municipal Code Chapter 10 Article 20. Regulations for the Control of backflow and Cross-Connections to the City’s Water System.

The City determines which type of backflow prevention is required based on the degree of hazard that your property presents to the potable water system.

  • Air Gap (AG)
  • Double Check Valve Detector  Assembly (DCDA)
  • Reduced Pressure Principal Assemble (RP)
  • Pressure vacuum breaker assembly (PVB)

What is backflow?

Engineers design water systems so that water flows from the distribution system to customers. However, unusual hydraulic conditions can cause the water to flow backwards—from the customer’s plumbing system into the public water system. Backflow can occur at any existing or potential physical “cross connection” between a public water system or the customer’s water system and any source of liquid, solid, or gas that could contaminate the water supply.

What cause a backflow:

Backsiphonage occurs when pressure in the public water system drops below the customer’s plumbing system pressure during fire fighting, water main breaks or sheared hydrants.

Backpressure occurs when pressure in a customer’s plumbing system rises above the public water distribution supply pressure. 

Things you can do to prevent backflow:

  • Be aware of and eliminate cross-connections.
  • Maintain air gaps. Do not submerge hoses or place them where they could become submerged.
  • Use hose bibb vacuum breakers on fixtures (hose connections in the basement, laundry room and outside).
  • Install approved, testable backflow prevention assemblies on lawn irrigation systems.
  • Install an approved, testable backflow prevention assembly at your home's water service connection.
  • Do not create a connection between an auxiliary water system (well, cistern, body of water) and the water supply plumbing.

What is an Approved Backflow Prevention Assembly (ABPA)?

A backflow prevention assembly is an approved, testable assembly which uses check valves and/or relief valves, in different configurations, to prevent potential contaminants for flowing into the potable (drinking) water system. An approved backflow prevention assembly has gone through an approval process at the Foundation for Hydraulic Research and Cross-Connection Control at the University of Southern California. This is a two-step process of laboratory tests and a 12-month field test. Only assemblies successfully completing the entire testing procedure are recognized by the City as approved backflow prevention assemblies.

For more information please contact:  

Armando Aguilar Water Operations Manager-Cross Connection Control Specialist
(310) 412-5480  

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