Locating Sprinkler Valves

Irrigation solenoid valves are the gatekeepers to your sprinkler heads.
They are connected to the water source for your irrigation and control the flow of water to each sprinkler "zone" or section. If you have a five zone system you have five valves.
Quality solenoid valves are built to perform under adverse conditions. They lay quietly in the ground doing their job year after year, covered in dirt and water. As with any equipment that is made up of moving parts, they will eventually wear out and fail.
Sprinkler valves generally fail in one of three ways:
* They will stick open and run 24 hours a day until the water source is turned off.
*They will constantly leak a small amount of water, known as "weeping".
*Or they will not turn on at all.
The problem is that after 15-20 years of being out of site and out of mind, when they fail---how do you find them?
The best and easiest way to locate a valve is with a specialized tool called a valve locater. However, these devices are expensive to purchase and generally not for rent. So before you go to the expense of hiring an irrigation contractor to find your malfunctioning valve, here are some places to look:
First, check near your water source. Many homes have their irrigation system connected to their house water (versus connected to a pump). Most city water systems will have an above ground back flow preventer. This is a metal device with handles on it to turn off the sprinkler water without turning off the water to the house. It should be located near where the water from your city meter goes into your house.
After finding the back flow preventer, take a 12" screwdriver and GENTLY probe a six foot area around the back flow. Take care to probe slowly as to not puncture any pipes. If you hit something solid , probe around this spot six inches in diameter. If you hit anything smaller than that, keep looking.
The next place to look is where the sprinkler timer is located. Check this area in the same way as you probed the back flow area.
Another indicator to determine the location of the valve is to turn on the defective zone and determine which sprinklers pressurize first. The first heads to pressurize are the ones closest to the valve. Obviously, this will not work with valves that will not come on.
Quite often, the valves will not all be placed in a central location. They will be scattered throughout the yard. A very common location is on the corners of the house.
Because your system was probably installed with a walk-behind-trencher, the valves will be at about two feet off of the walls.
Although buried sprinkler valves can be difficult to find without a valve locator, with some patience and a little luck, they can be found.