Swimming Pool Leak Detection
Swimming pool leaks are not uncommon. Diagnosis of a swimming pool leak is normally best left to professionals, but there are several steps you can take to narrow down the cause of the leak. As leak detection is so expensive the more information you can supply to the pool company the faster they can find the problem - you never know, you might even find it yoursefl!
A swimming pool leak can be a nightmare for the pool owner.
The cost of an untreated swimming pool leak can be enormous, not just in terms of lost water, but also with problems that can be created by the water that has escaped from the pool. By understanding the possible causes it may be possible to repair the leak yourself. Untreated swimming pool leaks can, over time, cause subsidence and structural problems for the pool or near by buildings.
So what do I do?
Gather information and eliminate possible causes. This will narrow down the places where a leak could be. Most tests should be done with water in the pool. This is very important if you need a pro, much of their equipment is dependant on saturated ground, but consult them first as some tests can be done without water in the swimming pool. It is futile to allow the water to find its natural level and assume its at the closest fitting. In 9 times out of 10, the leak is not in the pipe you think. Many of the pipes form a U bend. Or they are interconnected.
All of these steps can be taken by the home owner, but sometimes a specialist is needed. On the Costa Del Sol, Specialised Swimming Pool Repairs, have the latest in pressure testing, noise correlation and micro CCTV equipment.
Find out if the swimming pool is actually leaking.
Sometimes there is more evaporation than normal or a valve may have been left open etc...Perform a bucket test (details below). Checks on pump house plumbing. Establish if it is a suction leak or a pressure leak. Tests on lights and structure. Inspection of most common leak areas. Fluid for repairing leaks.
Evaporation. Most pools loose around 1inch or 25mm per week even in hot weather. This can triple, if heavy bathing is combined with very hot weather or heavy wind.The bucket test will show if the pool is leaking. The method is to half fill a bucket with water, put this on the top step of the pool. Mark the level of the water in the bucket and the level of the water in the pool. Leave for 24 hours, then measure the amount that each has dropped. If the water level in the pool has dropped more than the water in the bucket, there is a leak. If both have dropped the same amount, the water loss is due to environmental concerns.
A leak has been established. Now what?
First check the integrity of the selector valve. If the selector valve has failed, water will be leaking into the drain when the motor is running. To check this, set the valve to FILTER, turn on the pump, then watch the glass vial behind the selector valve. On some models it can be unscrewed. If water leaks out under pressure the selector valve has failed. The best solution to this is to replace the selector valve. In some cases this is difficult, the valve may be obsolete, or be in a difficult place to access. If the leak is not too great a stop valve can be put into the drain pipe to stop the leak. (remember to open this when the filter needs to be backwashed). This is often the cheapest solution. Look for signs of ground movement or subsidence around the pool. This should suggest areas to investigate, however if the ground has moved at one corner, this may have put pressure on the pipe and broken a joint further away.
Is it a suction leak or a pressure leak?
There are a couple of clues to establish this. Suction leaks will display the following symptoms. Poor suction, pump very slow to prime- air locked, air in the return to the swimming pool, air in filter or pre-filter. To establish a pressure leak, turn off the pump for 24 hours. If the water loss is less with the pump off and more with the pump on, the leak is in the return (pressure pipe).If the leak is in a suction line, open the drain, close the hoover and skimmer valves. Run the pump and watch for the tell tail clues. If no air is present, close the drain and hoover and open the skimmer. If no air is present, close the other valves and open the hoover. If one combination fills the system with air, this is the leaking pipe. If it appears that the leak is in the skimmer, it is usually a break in the pipe below the skimmer basket. 
Testing lights and fittings
A test on lights and fittings can be done by looking for water flowing through the leak. You will need some sort of die. The method is to make sure that the water is still, then very carefully squeeze a small amount near to the suspected leak. If there is a leak, the fluid will be sucked in at the source. Areas to check are around cables for the lights, joints between jets, skimmers, sockets, or anything else that goes through the wall and into the pool.
Specialised Pool Repairs - Costa Del Sol