At the Point of Connection
Turning off your sprinkler system from the controller works well when there are no leaks and when your controller is functioning properly; however, if there is a leak, or your controller isn’t working, turning off the Sprinkler controller will not stop the flow of water to the sprinkler system. Turning off the water to your sprinkler system involves closing the valves at the point of connection/backflow preventer. All sprinkler systems get their water source from somewhere, and typically this point of connection is in the vicinity of the water meter.
Inside the backflow preventer box are two levers. One lever closes the valve that controls the water coming into the backflow preventer from the water meter, and the other controls the water that leaves the backflow preventer, going to your sprinkler system. When it comes down to it, it does not matter which valve you close. To close the valve, turn the lever 90 degrees (a quarter turn). Sometimes the levers are old and rusty or even broken off. If this is the case, do not try to turn it. It is very possible that when it closes it will be stuck closed and then the whole valve shut will have to be replaced. In situations such as this, please call a professional.
At the Ball Valve Shut-off
Most newer sprinkler systems are required to have a ball valve that can be a more reliable, and easier, shut-off. If your system has a ball valve, it is typically located in front of the house, between the street and sidewalk. It is located directly downstream from the point of connection, on the sprinkler system side. A ball valve is very easy to use and will not rust out. Just like with the control box above, turn the lever 90 degrees to close the valve and stop the flow of water to your sprinkler system. If you do not have a ball valve, I would recommend having one installed. It does not require permitting or testing.
At the Water Meter
If all else fails, turn the water off at the water meter. Unfortunately, this will turn the water off to your home as well however, this may be your best option to stop the uncontrolled flow of water down the street. Unlike the double check valve and the ball valve, you will need to turn the handle a full 180 degrees to stop the flow of water. You will likely need a special key/pliers.