Have you ever wondered what a stop and waste valve is? Usually people refer to it as the “sprinkler main shutoff” that is 4-5 feet in the ground and is turned off by that long “T-bar.” It’s essentially an isolation valve which allows you to shut off the sprinklers in the winter without shutting off the water to your house. Shutting the stop and waste valve off also allows part of the main sprinkler line to drain in order to reduce the chance of pipes freezing and breaking.
How is it set up?
When installing a sprinkler system, a Sprinkler Technician will physically dig down to your main water line which comes from the city via the water meter out near the road and enters the house through your foundation. Older lines were made out of galvanized steel but the transition to copper main lines was made in the 70’s and 80’s. In new homes, you’ll find typically find copper.
This main line supplies culinary water to your property. The sprinkler technician will cut into the main line somewhere between the water meter and where it comes through the foundation of the house and install a “compression T.”
The stop and waste valve is attached via the compression T and runs in a perpendicular direction to the main culinary line. From the stop and waste valve the water runs toward the sprinkler valves located in the green valve boxes throughout your yard.
Why is it called a “Stop and Waste Valve”?
It’s quite simple really. When you turn the water off in the Fall, this “stops” the flow of water past the valve. When it is in the off position, a hole is opened up at the bottom of the valve which allows water between the stop and waste and the regular sprinkler valves to drain out; thus, “wasting” the water out. This “wasting” significantly decreases the chance of pipes freezing and breaking during the winter, at least in the main sprinkler line. To guarantee that all the water is removed from all the lines, the system should be blown out with an air compressor.
Replacing a Stop and Waste Valve
A commercial grade stop and waste valve should last 20-30 years. Sometimes they can last beyond that. The tell-tale sign of a broken stop and waste valve in need of replacing is when water flows steadily from the pipe the T-bar is inserted down to turn the valve on and off. It may flow slowly or at a rapid pace. It could flow when the valve is in the on or off position or both though typically it is when it is in the on position. The seal inside of the valve has worn out at this point.
Another sign of needing to be replaced is when the valve may become increasingly difficult to turn with the T-bar. When this time comes, don’t look to Home Depot for the part. Home Depot has many useful products but stop and waste valves are not one of them! The material and design are poor. I’ve replaced them as soon as two years after they were installed because the top snapped off when turning the valve on.
Finally, there are several other important steps to take while replacing a stop and waste valve. I always use commercial grade parts and use a particular brand of valve that has a wider nob on top allowing for significantly easier use. As an added measure of stability, I add a brass elbow just after the stop and waste valve to route the flow of water upward toward the level of the regular sprinkler valves. Some use a pvc elbow which has the tendency to snap if too much torque is used with the T-bar when turning the valve on or off. I also lay a gravel bed directly under the valve as a drain field and to keep dirt away.
If you believe your stop and waste valve may be in need of replacing, give us a call and we’ll come provide a free diagnosis.