Question 1

Is my pool leaking, or is it evaporation?

Accepted Answer

Evaporation is steady and depends on the weather. On the North Carolina coast in summer, a pool usually loses about a quarter of an inch a day to evaporation, and a little more in hot, windy weather or when the pool is heated and uncovered. A leak loses more than that, continues on cool, still days and does not slow down when the weather does.

The bucket test answers the question in 24 hours. Fill a bucket with pool water, set it on a step so the rim is above the surface, mark the water level inside the bucket and the pool level outside it, and turn the pump off. A day later, compare the two marks. If the pool level dropped noticeably more than the bucket level, the difference is a leak, not evaporation.

If you are not sure, call us and we will walk you through the test at no charge.

Question 2

How much water should a pool lose in a day?

Accepted Answer

Losing a quarter of an inch a day is normal evaporation for most of the year here, and up to half an inch is normal in hot, dry, windy weather. Loss approaching an inch a day, day after day, should be treated as a leak until proven otherwise. Two inches a day is clearly a leak, and you should call us the same day.

Measure at the same spot on the tile line at the same time each day, with the pump off if possible, so splashing and the pump’s operation do not skew the reading. Heavy rain can hide water loss for a day or two, so measure again once the weather settles.

Question 3

Why does my pool lose water only when the pump is running?

Accepted Answer

Water loss that occurs while the pump is running and stops when it is off points to the pressure side of the plumbing: the return lines from the equipment pad back to the pool, and the fittings where they enter the pool wall. Under pressure, water is forced out through any break. When the pump is off, the same break stays quiet.

Air in the pump basket or bubbles from the returns can be a related sign, though that usually means the suction side is drawing air. Either way, the next step is to isolate the lines and pressure-test them one at a time instead of guessing where in the yard the leak might be.

Question 4

Why does my pool lose water when the pump is off?

Accepted Answer

Water loss that continues with the equipment off points to the pool structure, the suction side of the plumbing, or the fittings and penetrations: the skimmer throat, returns, light niche or main drain. This pattern rules out the pressure-side plumbing, which narrows the search considerably.

Watch where the level stops. If the pool drops and then holds at a certain height, the leak is at that height, such as the bottom of the skimmer opening, a return fitting or the top of the light niche. If the level keeps dropping without stopping, the main drain, the shell or a suction line is more likely.

Question 5

What does it mean if my water level dropped and then stopped?

Accepted Answer

It means the leak is at, or just above, the level where the water stopped. Water cannot escape through an opening it is no longer touching. A pool that settles at the bottom of the skimmer opening usually has a leak in the skimmer body or the seal between the skimmer and the shell. A pool that settles around the light is often leaking through the light niche or its conduit. A pool that settles at a return fitting has a leak in that fitting or its return line.

Do not let the pool drop further to find out. Refill it to the normal level and call us. A pool left low in coastal ground can lift or crack, and a low water level puts the pump at risk of running dry.

Question 6

How can I tell if a pool with an autofill is leaking?

Accepted Answer

An autofill hides the most obvious sign of a leak, a dropping water level, by topping up the pool around the clock. The remaining signs are indirect: a water bill that rises for no clear reason, chemical levels that will not stay balanced because fresh water keeps diluting them, a fill valve that seems to run constantly, algae in a pool that used to stay clear, or wet ground and soft spots that never dry.

To check, turn the autofill off for 24 hours and do the bucket test. If the pool level drops more than the bucket level, the autofill has been hiding a leak.

Question 7

What should I look for around the equipment pad?

Accepted Answer

Look for a wet pad when nothing has been running, drips at unions and pipe fittings, standing water under the pump, a pump that loses prime or needs priming every morning, air in the pump basket, or a filter pressure reading that has changed for no reason. Ground between the pad and the pool that stays soft or green without rain points to a leak in a buried line.

Leaks at fittings on the pad are the easiest to see and the least expensive to fix. Leaks in buried lines between the pad and the pool need to be located before anyone digs.

Question 8

Where do most pool leaks happen?

Accepted Answer

Most leaks happen around the parts that pass through the shell: the skimmer, the return fittings, the light niche and the main drain, as well as the plumbing joints just behind them. The shell itself, whether plaster, gunite, fiberglass or vinyl, leaks less often than people expect. When it does, the leak is usually at a crack, a seam or a penetration rather than in the open floor.

That is why leak detection checks each system one at a time. Each of these areas fails in its own way and sounds different during testing, and ruling them out in order is faster than searching the entire pool.

Question 9

What are the signs of a skimmer leak?

Accepted Answer

The most common sign is a water level that drops to the bottom of the skimmer opening and then holds. The skimmer is a separate box set into the pool wall, and a seal can fail at the joint where it meets the shell, at the throat or at the faceplate screws. Dye drawn into a hairline crack at the throat confirms the leak.

Skimmer leaks can usually be reached without major excavation, which is why it is important to confirm one before any digging begins. A leak farther along the skimmer line is a different repair and tends to show up as air in the pump instead.

Question 10

Can a pool light leak?

Accepted Answer

Yes, and it is one of the most common leaks in an inground pool. The light sits in a niche with a conduit running back to the junction box, and water can escape through the niche seal or up the conduit where the cord enters it. A water level that settles just below the top of the light is the typical sign.

A light leak is confirmed with a dye test around the niche with the pump off. The repair is usually sealing the conduit or reseating the niche rather than structural work.

Question 11

What is a hydrostatic relief valve, and can it leak?

Accepted Answer

It is a spring-loaded valve under the main drain cover. If the water table rises above the pool floor, it lets groundwater into the pool so the shell is not pushed up out of the ground. On the coast, where the water table is high, this valve is important.

Over time its seal wears, and a valve that no longer closes lets pool water escape into the ground. This shows up as water loss that continues with the pump off and does not stop at any particular level. The leak is confirmed with a dye test at the drain, and the valve is replaced without draining the pool.

Question 12

How do vinyl liner pools leak, and can the leak be found without draining?

Accepted Answer

Liners leak at seams, at the fittings cut into them for the skimmer, returns, lights and steps, at pinholes worn by an abrasive floor or a sharp object, and at the bead where the liner hangs from the track. Water escaping behind a liner washes out the base, so a wrinkle, a soft spot underfoot or a liner pulling away from the track can each be a sign of a leak.

Draining the pool is a mistake: an empty liner shrinks and can fail completely, and the evidence of the leak drains away with the water. Liner leaks are found with the pool full by testing each fitting and checking the liner itself.

Question 13

Do concrete and gunite pools leak through the shell?

Accepted Answer

Sometimes they do, at cracks, cold joints and around penetrations, but far less often than through the plumbing and fittings. A visible crack is not necessarily leaking; dye drawn into the crack with the pump off confirms that it is. Plaster crazing, a network of fine surface cracks, is cosmetic and rarely lets water through.

Coastal soil shifts, so a leaking structural crack should be confirmed before it is patched. A patch over a crack that is still moving will not last.

Question 14

Can a leak be under the concrete deck?

Accepted Answer

Yes. The lines from the equipment pad to the pool run beneath the deck, and a joint or a section of pipe there can fail with age, ground movement or poor original installation. Signs include water loss while the pump is running, soft or sunken sections of deck, and wet soil along the edge of the deck.

Finding the leak does not mean tearing up the deck. The lines are isolated and pressure-tested to identify which one is losing water, then acoustic listening pinpoints the break, so the opening is a small cut rather than a trench.

Question 15

How does professional pool leak detection work?

Accepted Answer

We use three methods, in order. First, the pool’s systems are isolated and each plumbing line is pressure-tested on its own, which shows whether a line is losing water and which one. Next, acoustic listening follows the sound of water escaping a pressurized line to a precise point rather than a general area. Finally, dye confirms a suspected leak in the shell or at a fitting. Nothing is opened to find the leak.

You receive the findings in a written report: what was tested, what was ruled out and where the leak is.

Question 16

What is a dye test, and can I do one myself?

Accepted Answer

Dye is heavier than water. When it is released slowly beside a suspected crack or fitting, with the pump off and the water still, it is drawn into an opening that is leaking and drifts away from one that is not. Dye confirms a specific spot; it cannot search the whole pool.

You can try it yourself at a skimmer throat, a return fitting or a visible crack using a syringe and food coloring. Keep the pump off, wait for the water to go still, and hold the tip within an inch of the spot. If the dye is drawn in, that spot is likely leaking. If it is not, you have ruled out only that spot.

Question 17

Should I drain the pool to find or fix a leak?

Accepted Answer

No, especially on the coast. The weight of the water holds a pool in the ground. If a pool is emptied where the water table is high, the shell can lift, crack or float. An empty vinyl liner shrinks and may not fit properly again. A drained pool also has no water pressure to draw in dye or carry sound, so the leak becomes harder to find, not easier.

Leak detection is done with the pool full, and so are most repairs.

Question 18

What do I need to do before a detection visit?

Accepted Answer

Keep the pool filled to its normal level with the equipment in working order, and note what you have observed: how fast the level drops, whether that changes when the pump runs and where the ground is wet. Testing goes faster when the water is clear enough to see the floor and fittings.

Question 19

What does a pool leak cost if I ignore it?

Accepted Answer

First, there is the water: an inch a day from an average residential pool is several hundred gallons every day, and your water bill rises with it. Next are chemicals, because every refill dilutes the water you have balanced. Then there is the ground: water escaping under a deck or behind a wall washes out the base, which is how decks settle, tiles crack and liners wrinkle. A small leak left for a season often turns into a larger repair.

Finding a leak early keeps the repair small.

Question 20

What does pool leak detection cost?

Accepted Answer

Leak detection starts at $375. The exact price depends on your pool and the problem. We give you a quote for your pool before we start, so you know the price before any work begins.

Question 21

Does homeowners insurance cover a pool leak?

Accepted Answer

Usually not for the leak itself. Most policies exclude gradual damage, wear and seepage, which describes most pool leaks. Sudden, accidental damage from a covered event, such as a fallen tree or a lightning strike, may be treated differently, and some policies classify a pool as an “other structure” with its own limits.

Check your policy or ask your insurance agent. We are not an insurance company and cannot tell you what your policy covers. What we can provide is the written report from the detection visit, which is what an adjuster will ask for.

Question 22

Can a hurricane or a heavy storm cause a pool leak?

Accepted Answer

Yes. Saturated ground and a raised water table push on the shell from outside, shifting soil puts stress on buried lines and the joints where they enter the pool, and debris and storm surge can damage fittings, skimmers and equipment. These leaks often appear weeks later, once the ground drains and the water level starts to drop.

After a storm, do not drain the pool to clean it. While the water table is high, the water in the pool is what holds it in the ground. Clear out the debris, run the bucket test once the weather settles, and call us if the pool is losing more water than it should.

Question 23

Should a closed pool lose water over the winter?

Accepted Answer

A properly winterized pool with plugged lines should hold its level, apart from a little evaporation through a mesh cover on dry, windy days. If a closed pool keeps dropping, it is losing water through the structure or a fitting rather than the plumbing, because the lines are plugged.

Watch the cover. A safety cover sagging into the pool is usually the first sign. Top up the pool so the cover is not strained, and have it checked before opening season rather than after, when the wait is longer.

Question 24

Do saltwater pools leak differently?

Accepted Answer

They leak in the same places, but salt water is harder on metal. Fittings, light niches, heater connections and rail anchors corrode faster, and a corroded fitting is a common leak point in a saltwater pool. A salt level that keeps falling for no clear reason is also a sign of water loss, because salt leaves with the water and fresh fill water dilutes what remains.

Question 25

Could my spa be draining into the pool?

Accepted Answer

On a shared pool and spa system, the spa sits higher, and a check valve keeps it from draining into the pool when the pump stops. If that valve sticks open, the spa empties into the pool overnight and the pool level rises. That is a valve problem, not a leak, although the two are easy to confuse.

If the spa loses water while the pool level holds steady, the spa has its own leak, in its returns, jets, light or the plumbing beneath its shell. Isolating the spa’s lines is how the two are told apart.

Pool leak questions, answered

Is it a leak?