Annual Backflow Testing Requirements

Backflow assemblies which are not tested annually pose a greater risk to the customer's home and the public water system.  Due to the seriousness of this risk, the State authorizes water purveyors to discontinue water service until it is determined the risk is no longer present.

Yes.  During a typical year, we will mail backflow testing reminder letters to residences who we do not have record of a passing annual backflow assembly test report.  First notices are mailed in March.  If needed, second notices are mailed in May and third/urgent notices are mailed in August.

The State and TVWD require all non-potable water sources, such as irrigation/sprinkler systems, have backflow protection.

Atmospheric Vacuum Breakers (AVBs) provide backflow protection (when installed properly to code) and are not subject to annual testing requirements.  AVBs do however, require regular inspection to ensure they are functioning properly.

In some instances, TVWD does not have record of a customer's backflow assembly and we are unable to send reminder letters to those customers about the annual testing requirements.  In addition, the customer may not familiar with backflow protection and its importance.

This is not a simple question to answer.  At a minimum, a hose bibb should have a hose bibb vacuum breaker or Atmospheric Vacuum Breaker (AVB). A hose bibb vacuum breaker is a threaded device that screws onto the spigot mouth. It prevents water from flowing backward into your pipe with a spring loaded check valve. This valve opens and closes based on the water pressure.

When the water flows, the pressure of the water pushes open the check valve in the hose bib backflow preventer. When you turn off the water, the pressure against the spring on the valve decreases, the valve closes, and air flows into the space around the valve. The air pressure and the spring keep water from seeping back into the spigot from the outside.

AVBs are the simplest and least expensive of devices intended to keep water from flowing back into the water lines. They operate by using the outside air pressure to close a check valve. When you turn on the water, the water pressure pushes open the water valve. When the water is off, the air pressure pushes down on the valve and blocks the pipe.

There are installation requirements for AVBs.  Atmospheric vacuum breakers require that they be installed at least 6-inches above all downstream piping and outlets. This is to eliminate the potential of backpressure. If the downstream piping or outlets are above the vacuum breaker then the resulting backpressure may flow back (backflow) through the vacuum breaker. In addition, there should not be any valves (shutoff valve or timers) downstream from the vacuum breaker.

Laying a hose on your lawn and attach a rotating or oscillating sprinkler head to the end of the hose is not a concern.  However, if your hose bibb is connected to an in-ground irrigation system or drip system piping, these are more permanent examples of an irrigation system and should be properly protected from backflow.  Our staff may discuss the details of your particular irrigation system and provide recommendations.