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Sprinkler and Irrigation Systems Services
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Residential Maintenance & Repair
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Modifications / Retrofits / Upgrades
Sprinkler System Maintenance for Homeowners
Consumer Education Series
Function of Isolation Valve
The isolation valve is the positive shut off point of all water from the sprinkler system. It allows water supply to the sprinkler system to be shut down, (isolated), without interrupting water service to the residence. It is extremely important that this valve be accessible and operable. A malfunctioning, or damaged sprinkler system can waste a tremendous amount of water in a very short period of time. Law requires that professional licensed irrigators install an approved backflow prevention device. The valves used on these devices can be utilized to "isolate" the sprinkler system as well as perform the backflow prevention function. These valves are generally, (but not always), located near the city-owned water meter, (often near your front curb). In most cases, they are enclosed in a plastic or concrete/steel valve box. Many times they are covered over with grass or mulch, so invisible to the untrained eye. It is extremely important that the valve be accessible. Even those boxes which are visible and accessible may contain a valve which is so buried, and corroded, that it is inoperable. The importance of this becomes fearfully evident when 30 gallons per minute, (or more), of your precious water is gushing down the gutter! Locate and inspect your sprinkler system isolation valve. Note its condition and operability. Remember, in an emergency, unplugging the controller, and taking the battery out, is not going to stop the water! If you cannot find the isolation valve immediately, shut off the water meter if possible, then look for it, (or call a professional).
Function of Backflow Prevention Valve
A properly installed backflow prevention device protects the public potable water supply from potential contaminants, (such as pesticides, herbicides, or fertilizers), that may enter through your sprinkler system. The most commonly used backflow prevention device for modern irrigation systems in Texas are double check-valve assemblies. When these devices are installed and operating properly, they allow water flow in only one direction. Therefore in cases where there is a temporary loss of pressure on the "city side" of the meter. (like an open fire hydrant, or water main repairs), the device stops potential back-siphonage, or backflow into the potable water supply.
Texas law requires that some type of backflow prevention device be installed on all irrigation systems. The Texas Commission on Enviromental Quality, (TCEQ), regulates and enforces compliance with these laws. Municipal water departments, or building inspection departments require permits, and testing of these devices upon installation.
Unfortunately, many older irrigation systems, (and some newer ones), do not have a backflow prevention device in place. Contaminated water can pose serious health risks, incidents or back-siphonage have been documented to have caused illness and death.
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