A leaking hydrostatic relief valve may be responsible for your pool’s water loss. This is an easy repair for a qualified diver who will replace the valve without draining the pool. Hydrostatic valve leaking is only a problem for inground concrete, gunite, or fiberglass pools.
What Is a Hydrostatic Relief Valve?
The hydrostatic relief valve, or HRV, is designed to maintain the pressure between the water in the pool and the water in the ground. This is important in Florida and other areas with a high water table. If the ground around the pool becomes saturated, it can cause the pool to “float.” A fiberglass pool can buckle in at the sides if there is not enough water in the pool to maintain equal pressure. A concrete pool may actually crack if the groundwater saturates the soil.
Although you don’t want dirty groundwater in the pool, it is better to allow some of that water into the pool to stabilize pressure when necessary. This may occur after heavy rain from a tropical storm system.
You may not be aware that the valve is working to equalize pressure, even though the water is dirty after a storm. When you check your covered pool after a storm and the water is cloudy, it might be from groundwater released into the pool by the valve. If you see this, it is probably time for a shock treatment with heavy chlorine.
Valve Location
Hydrostatic relief valve leaking can allow water to flow out of the pool and saturate the surrounding ground. This can create the problem the valve was designed to protect against, which is one reason you should replace the valve every five years.
The hydrostatic valve is located at the deepest part of the pool or close to the main drain. The drain is designed to suck water into the plumbing system through the PVC pipes. The water is pulled into the filter and the heater and returned to the pool. The system is the same for in-ground spa tubs.
The main drain, a suction system, may be covered with a plastic screen for safety and to keep debris out of the plumbing. The HRV is located within the drain assembly or nearby in its own covered box or sump. The plastic unit has a grate and a dress ring (large O-ring) over the valve unit. A stem from the valve protrudes into the gravel or ground beneath the pool. The valve opens to release pressure when the groundwater moves up through the stem.
The ring and grate can deteriorate with age, causing the hydrostatic relief valve to leak over time; they may also collect particles of dirt and rock. Aquaman Leak Detection has professional divers with the right equipment to open the enclosure holding the valve unit, remove it, and replace it with a new one. The process does not take long, and the valve unit is not expensive.
A leak caused by the HRV may begin small, but it can grow larger over time. It is a difficult problem to locate since many pool owners are not even familiar with its location or how to check it.
Call Aquaman Leak Detection if you suspect a problem with the drain or the HRV. We can check it out and replace the valve immediately, usually with same-day service throughout Florida.
Hydrostatic Valve FAQs
Can a pool leak through a hydrostatic valve?
Yes, a pool can leak through a hydrostatic valve if it gets stuck in the open position or if debris prevents it from sealing properly. When functioning correctly, the valve should only open when there’s excessive groundwater pressure and close when pressures equalize, but wear, damage, or obstruction can cause it to remain open and allow pool water to drain out.
What happens if a hydrostatic valve fails?
If a hydrostatic valve fails to open when needed, extreme groundwater pressure can cause the pool shell to crack, buckle, or even pop completely out of the ground, resulting in expensive structural damage. Conversely, if it fails in the open position, it will continuously leak pool water, leading to water loss and potentially allowing dirt and debris to enter the pool.
How to stop a pressure relief valve from leaking?
If the pressure relief valve is leaking, first try lifting and releasing the lever 2-3 times to flush out any debris that may be preventing it from sealing properly. If that doesn’t work, the valve likely needs to be replaced, or you should check if your system pressure is too high.
What is hydrostatic pressure in a pool?
Hydrostatic pressure in pools refers to the force exerted by groundwater underneath and around the pool structure when the water table rises above the pool’s base. This upward pressure can be significant during heavy rains or high water table conditions and must be managed to prevent the empty or partially filled pool from floating or being pushed out of the ground.