Service: pools and spas
Pool and Spa Leak Detection in Arcadia, CA
A pool that keeps needing top-ups may be losing more than evaporation. Here is how to tell the difference, how leaks in the shell, plumbing and equipment are found, and what to expect from a visit.
What is a pool or spa leak?
A pool leak is any point where water escapes from the shell, the fittings set into it, the pipes that circulate it or the equipment that treats it. Pools lose some water to evaporation every day, so the job of detection is to decide whether the loss is more than weather can explain, and if so, to find where it is going.
That matters here. Southern California has a long, dry warm season, and sun, wind and low humidity all speed up evaporation. A pool in that setting will always need some topping up, which can hide a real leak for a surprisingly long time.
Spas and hot tubs have the same weak points on a smaller scale. For a broader introduction to how professionals approach all the different kinds of leaks, see our full leak detection guide.
How are pool leaks found?
Providers work from the simplest checks to the more specialized ones, narrowing the search at each step. Because water loss can come from the structure, the plumbing or the equipment, the first aim is to work out which of the three it is.
- Loss tests: comparing the pool's level drop with and without the pump running shows whether the leak is in the shell or in the pressurized plumbing.
- Visual and equipment checks: a close look at the pump, filter, heater, valves and connections on the equipment pad often finds drips and wet soil.
- Dye testing: a small amount of dye released near a suspected crack, fitting or seam is drawn toward the leak, which makes the point visible.
- Pressure testing: lines are plugged and pressurized one at a time. A line that will not hold pressure is leaking, and the others are ruled out.
- Electronic listening: sensitive microphones can pick up the sound of water escaping from underground plumbing.
- Underwater inspection: a diver or camera examines the shell, light niches, returns, skimmer throats and the main drain.
Most leaks are found by combining two or three of these. A written note of which lines and fittings were tested and ruled out is useful, because it saves repeating the work during repair.
What are the signs of a pool leak?
Because evaporation muddies the picture, it helps to look for several signs together rather than just one.
- Water level keeps droppingThe pool loses more than weather explains, or the loss speeds up.
- Frequent top-upsYou add water far more often than before, or the auto-fill runs constantly.
- Wet soil or pooling near the poolSoggy ground, standing water or lush growth around the pool or equipment.
- Cracks in the deck or shellNew cracks, lifting coping or settling paving near the pool edge.
- Pump losing prime or drawing airAir in the pump basket or lines can point to a suction-side leak.
- Algae despite good chemistryConstant dilution of treated water makes it hard to keep chemicals balanced.
- A higher water billAdded fresh water shows up as extra usage on your bill.
- Damp equipment padMoisture, rust or mineral stains around the pump, filter or heater.
What causes pools to leak?
- Shell cracks and plaster failure: ground movement, age and shifting water pressure can crack the structure or wear through the surface.
- Fitting seals: the skimmer, return jets, light niches and drain are cut into the shell, and their seals and gaskets age.
- Underground plumbing: the pipes behind the pool are buried, so a failed joint or a cracked section can leak for a long time unnoticed.
- Equipment: worn pump seals, loose unions, valves and heater connections drip steadily.
- Liner damage: in vinyl-lined pools, tears, folds or failed seams around fittings can let water out.
- Deck and soil movement: settling alters support and stresses joints and pipes.
Water supply can add confusion. A sticking auto-fill valve adds water without any leak at the pool, and a break in the supply line behind it is a case for water line leak detection. Wet soil near the pool may also come from sprinklers, so irrigation checks are often part of the process of elimination.
What can you check before calling?
Two simple tests will tell you a lot before anyone arrives.
- Do the bucket test.Fill a bucket with pool water, set it on a pool step so the levels inside and outside are equal, and mark both. Leave it for a day without swimming or adding water, then compare. If the pool dropped noticeably more than the bucket, you likely have a leak.
- Repeat with the pump off.Run the same test over another day with the pump and any auto-fill switched off. If the loss shrinks a lot, the leak is more likely in the pressurized plumbing or equipment. If it stays the same, the shell or fittings are more suspect.
- Inspect the equipment pad.Look for drips, rust, wet ground and mineral crust around the pump, filter, heater and valves.
- Check the auto-fill.Make sure it is not stuck open and masking a leak or adding to your bill.
- Keep a level log.Note the water level at the same time each day and when you top up. After a week, the pattern is usually clear. Our guide to high water bill leaks shows how to connect the log to your usage.
Warning: do not drain an in-ground pool on your own
Emptying an in-ground pool can allow groundwater to lift or crack the shell. Ask a professional before lowering the water level significantly. Also switch off the pump if the water falls below the skimmer, since running it dry can damage it.
What happens during a pool leak detection visit?
The details vary, but the sequence is usually this.
- A short history.The technician asks how much water you lose, how long it has been going on and whether you have already done a bucket test.
- Equipment and surface check.They look over the pad, the pool deck, the skimmer and the visible fittings.
- Loss testing.They confirm whether the loss is in the shell or in the plumbing, usually by running the system and comparing levels.
- Dye and pressure tests.Suspect cracks and fittings are dye tested, and the lines are isolated and pressure tested one by one.
- Listening and underwater inspection.Electronic listening equipment and an underwater look help find leaks that tests alone cannot place.
- Report and options.You are told where the leak is and which repair routes are possible. Ask for the findings in writing.
Repair is a separate job. A shell crack, a failed seal and a broken buried pipe call for very different work, and the cost and disruption follow from that, so compare quotes once you know the cause.
What affects the cost of pool leak detection?
Each provider sets their own pricing. To see how these factors compare across all service types, read what affects leak detection cost, and then consider the pool-specific variables below.
| Factor | How it changes the job |
|---|---|
| Pool type | Plaster, vinyl and fiberglass pools each fail in different ways and call for different checks. |
| Plumbing complexity | More lines, features such as waterfalls or spillways, and a larger equipment setup mean more to isolate and test. |
| Spa or water features | A connected spa or extra features add fittings and lines to test. |
| Access to equipment | A clear equipment pad and labelled valves speed up isolation testing. |
| Water level needs | Some checks are done at a specific level, which may require waiting or adjusting. |
| Report | Ask whether a written summary of what was tested is included. |
When is a pool leak an emergency?
Act quickly if the level is falling visibly over a few hours, if soil is washing out or sinking around the pool, if the deck is cracking or lifting, or if you see water surfacing in the yard near the pool plumbing. These point to a fast leak that can undermine the surroundings.
Protect the equipment and the yard
Switch off the pump if the water drops below the skimmer, keep people and pets away from any area where soil is sinking, and call for help. Do not run the system dry or try to empty the pool.
Pool leak detection FAQs
How can I tell whether my pool has a leak or is just evaporating?
Evaporation is steady and weather-driven, so it slows on cool, calm, humid days. A leak keeps taking water regardless. The bucket test described above compares the pool's loss with a bucket of water losing only to evaporation, which is the simplest way to separate the two.
Does pool leak detection mean draining the pool?
Usually not. Most tests are done with the pool full. Some situations, such as repairing a crack in the shell, may need the level lowered, but you should not drain an in-ground pool completely without professional advice.
Is it normal to add water to my pool regularly?
Some top-up is normal, particularly in dry, windy or hot weather. What is not normal is a loss that is larger than the weather explains, or that suddenly speeds up. Keeping a simple log of how often you add water makes the difference easy to see.
Can a pool leak damage my yard or nearby structures?
A steady leak can saturate the soil around a pool, wash out support under decking and paving, and encourage settling. The risk grows the longer the leak runs, which is a good reason to investigate sooner rather than later.
Do spas and hot tubs leak in the same way?
Yes. They have the same kinds of weak points, including fittings, jets, pumps, heaters and plumbing connections, and the same tests apply on a smaller scale. Because the volume is small, a spa loss often shows up faster.
Does a pool cover help?
A cover reduces evaporation, which makes it easier to tell whether any remaining water loss is a leak. It does not fix a leak, but covered-versus-uncovered comparisons can be a useful clue.
Related services and nearby areas
Water loss around a pool can have several sources. These related guides cover the nearby possibilities, and each neighborhood below has its own local page.