How to Find Underground Sprinkler Valves

With a Map

1). Locate your sprinkler system installation chart. This should be a map of your yard that was given to you by the company that installed the in-ground sprinkler system. It may not have the location of the underground sprinkler valve on it, but it will have the location where the main line and sprinkler heads exist in your yard.
2). Go to your water meter. This box is on the exterior of your house and commonly used by your local utility company to read your water consumption for the month. If you cannot find your water meter, go to your main sprinkler system control station, which is the box you use to control the system and set its timer.
3). Follow the irrigation map from the point you're standing -- at the water meter or control box -- to your underground sprinkler valve. Specifically, follow the main line on the map until you find the valve. The map should give you a detailed breakdown of exactly where the main line goes. The main line connects to the water meter or control box as well as to the sprinkler valve, so just follow the line across your yard until you find the box the valve is stored in.

1). Walk to the area of your yard where your sprinkler heads are located. These are the parts of the sprinkler that pop up out of the ground and water your lawn. These should be in lines stretching across the length or width of your yard.
2). Walk across the lines that form your sprinkler heads, looking for the lines to split off away from the heads in another direction. This is your main line. This typically happens at the location where the flow of your water splits in half, but there is no guarantee that this will be in the direct center of all your sprinkler heads.
3). Walk to the end of your main line. Nearby, you will see a box in the ground that contains your sprinkler control valves. This could be in your grass or in a patch of soil like a garden or bed of flowers. The box should be covered by some type of metal or hard plastic lid. Remove the lid to access your sprinkler valve.