Backflow is water flowing in the opposite direction from its normal flow. Water systems are designed to have higher pressure than a customer’s system to keep water flowing in the right direction. However, when there is a drop in water main pressure, a reverse flow – or backflow – can occur causing potentially contaminated water to enter the potable (drinking) water distribution system.

There are two ways in which backflow can occur:

• Backsiphonage: Backsiphonage can occur when there is a sudden reduction in the water pressure of the distribution system, such as during firefighting or when a water main breaks. At these occurrences, water flow can be reversed. This reversal can create a suction effect and draw potential contaminants into the potable water system.

• Backpressure: Backpressure is created when pressure from on-site pumps or auxiliary private wells in the customer’s water system exceeds the pressure in the potable water system. This can force the potable water to reverse its direction of flow through a cross-connection between the two systems. Potential contaminants can then enter the potable water system.

A cross-connection is a permanent or temporary connection between potable drinking water and anything that can pollute or contaminate the water supply. Any connection between the water meter and backflow assembly or a connection between an auxiliary water system (private wells, canal water and ponds) and the potable water supply plumbing are examples of a cross-connection. A backflow condition can result in water contamination if hazardous cross-connections exist. 

• Eliminate any connections on service line between water meter and backflow assembly.
• Do not submerge hoses or place them where they could become submerged in swimming pools and ponds.
• Install Indio Water Authority approved, testable backflow prevention assemblies.

A backflow prevention assembly is an approved, testable assembly, which uses check valves and/or relief valves in different configurations, to prevent potential contaminants from flowing into the potable water system. An approved backflow prevention assembly has gone through an approval process at the Foundation for Cross-Connection Control and Hydraulic Research (USC FCCC&HR) at the University of Southern California. Only low lead or lead-free assemblies are recognized by IWA as approved backflow prevention assemblies.  Here are the IWA approved backflow spec sheets for reference and sample backflow devices are listed below.

State and Federal law requires that water suppliers protect their potable water systems from contamination. When a determination is made, either by plan check and/or on-site inspection, that the potable 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.

Indio Water Authority makes these decisions based on a case-by-case basis. Residential, Apartment and Commercial customers demonstrating a high potential for contaminants to enter the potable water system must install and maintain backflow prevention assemblies. IWA will complete the annual testing of each backflow assembly and will notify customers if repairs to the assembly are required.

IWA provides a partial listing of certified backflow testers for your convenience to assist you in completing required repairs or installations to bring your water service into compliance. These testers have shown their competency to test backflow prevention assemblies. Alternatively, you may choose to use other contractors for backflow repairs or installations. In order for installations or repairs to be approved for compliance by Indio Water Authority, the customer must provide a copy of a current CA-NV AWWA, or Riverside County Backflow Assembly Tester Certification, and proof of testing gauge calibration from the Certified Backflow Assembly Tester. Once the tester has completed the testing, then the original Test and Maintenance Report must be returned to Indio Water Authority.

Backflow devices are commonly made of low grade metals and they are stolen for their scrap metal value. The Indio Water Authority tests backflows to make sure they are working properly. The overall responsibility for maintaining backflows is the customer’s responsibility. This means that when a backflow is stolen, the customer must pay the cost of replacing it.

Paint the domestic backflow assembly. Domestic backflow assemblies may be painted  Hunter Green or Almond Tan to blend in with the current landscaping.  Backflow Serial Number information may not be painted. 

Install an IWA approved backflow cage to protect from theft. The cage must meet Indio Water Authority specifications. Customer are strongly encouraged, but not required to put a cage around their backflow device.  A cage cannot guarantee that the backflow will not be stolen.  Any padlock installed on backflow cages must be IWA approved padlocks.  Here is the  IWA enclosure spec sheet.  

Reduced-Pressure Backflow Prevention Assembly (RP)

RP devices have a relief valve located between two internally loaded, independently operating check valves together with tightly closing shut-off valves upstream and downstream of the check valves. RP devices are used on larger domestic and landscape service lines.

Double Check Valve Assembly (DC)

DC devices consist of two internally loaded, independently operating check valves together with tightly closing shut-off valves upstream and downstream of the check valves. DC devices are used primarily on isolated landscape service lines.

DCDA Double Check Detector Assembly (DCDA)

DCDA consist of two backflow assemblies, one on the main line and other on a bypass line. The bypass line contains a small IWA meter for detecting water use. A DCDA lacks a relief valve. DCDA assemblies are used on main fire service lines that contain no chemicals.

Reduced-Pressure Principle Detector Assembly (RPDA)

RPDA is similar to DCDA but is also equipped with a relief valve. RPDA consist of two backflow assemblies, one on the main line and other on a bypass line. The bypass line contains a small IWA meter for detecting water use. RPDA are used on sites where chemicals are added to a fire fighting system. RPDA provide additional protection compared to DCDA.