What Is A Hydrostatic Relief Valve
An HRV or hydrostatic relief valve is a check valve installed in the pool floor that allows the water table outside of the pool to stabilize with the pool water if hydrostatic pressures under the pool build up. This would be common during periods of heavy rainfall like in the spring when water tables are at the highest.
Any time that the pool is empty enough that you have access to the main drains it is strongly recommended to replace the HRV. The one way valve is operated by a mechanical seal actuated on a spring.
This means that it is possible for the spring to rust or mechanical wear to develop on the moving parts. Just to be safe it is a good idea to replace this valve in the main drain any time you have the opportunity.
Hydrostatic Relief Valve
Other than the obvious condition that the pool can drain indefinitely, the only other obvious sign of hydrostatic relief valve failure is occasionally you will see a cloud of murky water appear at the bottom of your pool. This cloud is the ground water from beneath your pool accessing the inside of your pool. In short bursts, this murky cloud of water should be considered normal as the valve relieves the water table pressure.
Constant cloud or frequent clouding even during relatively dry periods should be considered abnormal operation for the hydrostatic relief valve. It is a mechanical connection, meaning it relies on moving parts in order to operate, and it will wear out eventually and thereby requires periodic replacement as preventative maintenance. Each time you replace your liner, be sure to have this inexpensive item replaced as well and you should be fine.
The menu on the right is a chronological step by step process to determine where a swimming pool is leaking. This website is written as a readthrough technical assistance guide for locating leaks. When you believe you have identified where the pool is leaking you need to go to our sister website to see pictures and learn more about the actual swimming pool leak repair process.