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Pool & Spa Tips

20 September 2019
5 Spot Checks to Detect a Leak in Your Pool

A leaking pool will not only lose a large volume of heated water, but it can cause structural damage to the pool and surrounding building. Follow these tips to spot and stop leaks before they do lasting damage.

Tip #1: Check the filter multi-port valve
If your pool is losing water, the cause could be the gasket in the multi-port valve. The seal between the ports of the value may have worn, allowing water to trickle out through the waste port. This can be checked by detaching the waste connection to the multi-port but this is probably not a job you will want to tackle yourself. The engineer will be able to do this quickly and, if this is the cause of the leak, they will replace the spider gasket in the valve or replace the whole valve if necessary.

Tip #2: The bucket test
While a noticeable loss of water is usually a sign of a leak in the pool, if you have an outdoor pool and the weather has been very warm, the water could be evaporating in the high temperature.  When the weather conditions are suitable and the pool is not being used, do the ‘bucket test’ – place a bucket, filled with pool water, on the pool steps and weight it with something heavy (eg large garden stones).  Mark the water levels inside and outside of the bucket (should be identical at the start of the test) and as recommended by SPATA, leave it for seven days to get the most accurate result.  Articles/videos you find online often say to do the test for 24 hours (as does the video below) but we would always follow SPATA guidelines.  Check the water level after the test. If the water line has dropped more outside the bucket than inside, your pool has a leak. 

Tip #3: Inspect the pool liner
Older pool liners are susceptible to cracks, tears and small holes so conduct periodic checks, especially around fittings such as the pool steps, lights, skimmer, returns and suction line.  Testing a liner thoroughly includes the bottom of the pool and this could mean lengthy underwater work – for safety this is best undertaken by a professional servicing company. If you suspect that the liner is damaged, do call the company in quickly to ensure they can book the work as a priority. They will replace the liner which will protect the integrity of the pool.

Tip #4: Beware small cracks
The pool walls and floor of concrete pools should be inspected regularly to ensure that they are free from loose tiles and minor cracks, as these can lead to leakage. If bathers spot anything concerning when they are in the pool, the pool engineer will need to do a thorough inspection to find the little cracks and refurbish them and/or replace tiles. Unfortunately, not all pools are built to perfection and leaks can occur due to inadequate sealing, poor structural design or the use of mediocre materials. If you find yourself in this position, structural enhancements will need to be carried out by a reputable pool refurbishment company to make the pool watertight. 

Tip #5: Air bubbles in the water
A leak in the pool’s suction lines can damage the pool’s plumbing system.  If you see air bubbles in the water in the return line when the pump is running there is most likely a leak in the suction line. Air bubbles in the return line may also be caused by blockages in the suction line. Check all the  connections, seals, gaskets and o-rings to see if there is a problem that needs fixing. This video highlights the problem.

To find out more about London Swimming Pool Company's Servicing and Maintenance Programmes, please visit this page of our website.

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