The first step is to determine how much water the pool is losing. Once you know that it's easier to determine the cause and therefore possibly the location of the leak. Here are our suggestions:
Fill the pool to the proper operating level and mark the water level with tape, marker or crayon. Record the loss in 1/4 of inches, once in the morning and once in the evening for 24 to 48 hrs.
As a rule of thumb, losses up to 1/2 inch daily may indicate a combination of evaporation / wind / splash out. Losses up to 1 inch daily more than likely indicate a leak somewhere in the system, more than 2 inches of water loss per day would normally be caused by broken pipe, broken or loose fitting or by a visible hole or tear in the liner.
Cause 1: "Splash out" is lost through various activities in the pool including diving, water games, etc.
- Observation: Fill pool to operating level. If water level does not drop on days pool is not used, splash out is the cause.
- Cure: Warn pool users that splash out is the cause
Cause 2: The loss of 1/4" (up to 1/2" during excessive hot or dry periods) of pool water per day is an indication of water loose due to evaporation.
- Observation: Loss of water to evaporation will be noticeable in the morning as cooler night air causes a higher rate of evaporation than hot sunlight. Wind also contributes to evaporation.
Cause 3: Filtration/Plumbing System. If splash out and evaporation have been eliminated as probable causes of water loss, the next step is to check the filter / plumbing system.
- Observation: If water loss continues, the leak may be in one of the wall fittings, such as an inlet, skimmer, underwater light, or in the main drain. Us a dye, such as phenol red of a test kit. With the filter turned off, use dye in the suspected area and observe if it is drawn into the leak.
- Cure A: Check the pipe/hose connections at valves, filter and pump for leaks. If none are found:
- Cure B: Shut down the filter and plug the skimmer, main drain and all inlets. If water loss ceases, there is leakage somewhere in the piping. Check the lines by pressure testing them.
- Cure C: Allow water level to drop until it stops at either a tear in the liner or at one of the wall fittings, to indicate the leak is there. However, if the water continues to drop below the fittings or light cut-out add water to the pool to maintain pressure on the walls. The leak is at or below the low water level somewhere in the liner.
Cause 4: The liner. To locate a small hole in the liner will require someone with diving apparatus to search underwater for the hole. It is important that the pool be operational so the water is absolutely clear for the diver.
- Observation: Check the entire pool bottom starting at the liner seams and corners. If a particular area is suspect, the leak can be verified using a dye, such as the phenol red of a test kit, in the area and observing if it is drawn in to the hole.
- Cure: There are a number of underwater adhesives designed for patching vinyl liners without draining the pool; follow the manufacturer's instructions.