How Do You Know If Your Swimming Pool Is Leaking?

All pools lose some water due to evaporation, splash out and backwashing or vacuuming to waste, so it is normal to have to add water to your pool occasionally. But your swimming pool may be leaking if you routinely need to add more than a couple of inches to your pool per week, or if your water leveller seems to be topping up a lot. Here we explain how to tell if your swimming pool is leaking.

How can you tell what is normal water loss and what is not?

Follow our steps to check for problems that could cause your pool to lose water.

• Check for any signs of water leakage around the pump shed. Are there any damp or wet areas on the floor? Closely inspect the pump, filter, heater, chlorinator and any pipe joins/unions for drips or leaks. Any drips or leaks should be repaired as soon as possible.
• If you have a vinyl liner pool look for any rips or separation especially around any fittings in the liner, steps or corners. For all other pools inspect the pool surface for any cracks or deterioration in the surface. Sometimes the problem can be the size of a pin-hole and very hard to find.

To confirm a pool leak, do a bucket test. For this test, you will need a bucket or watertight container (a clear plastic container is ideal) and a couple of rocks or bricks to use as weights. If you have an automatic water leveller, turn it off while doing this test.

1. With the weights in the bucket, add pool water to the bucket so that when it sits on the pool step the water level in the bucket is the same as the water level in the pool.
2. Leave the bucket in place for 24 hours. During this time the pool cannot be used. If it rains or there are strong winds the test will need to be restarted.
3. Check the water levels after 24 hours. If the water level in the bucket is the same as the pool, there is no leak. If the water level in the bucket is higher than the pool you have a leak somewhere.
4. If this test indicates a leak, repeat the test with the pump turned off. If the water level in the bucket is the same as the water level in the pool when the test is repeated, the leak is likely in the pipework or equipment.

Please ensure the water level of the pool does not drop below the skimmer when running this test with the pump on.  If the water level drops below the skimmer, stop the test, turn off the pump and top the pool up with water.

If you have determined that the pool itself is losing water (not the equipment), to help identify where the problem is, you can turn the pump off and watch to see where the water loss stops. At the level where the water stops leaking, you will probably find the cause of the water loss.

• The skimmer or filtration system is probably the cause of the water loss if the water stops at the bottom of the skimmer.
• If the water stops at the light check the housing for the light.
• If the water is continuing to drop below the skimmer and the light, the problem could be the main drain (if the pool has one) or the surface of the pool.

Please note, fibreglass pools and vinyl liners always need to have water in them, so do not allow the pool to drain too far if you have a fibreglass pool or a vinyl liner. All pools are at risk of hydrostatic damage or earthquake damage when not full, so please consider this before doing this test just in case there is a leak on the lower part of the pool.

If you find a suspected leak point such as a crack or split, with the pump turned off, put a drop or two of pH indicator test reagent near the area. Watch to see if the reagent is drawn into the crack. If it is drawn into the crack, then the pool is probably losing water from this point.

What to do if your swimming pool is leaking

Not all leaks can be found using the above techniques. If you have found a leak or believe your pool is leaking, it may be time to call in the experts. We repair leaks in equipment and pipework above the ground. If your leak is not in this area, we can advise you who to contact for repair work in the Christchurch area.