Your Pool Keeps Losing Water. Here's How to Know If It's a Leak.

Your pool loses water every day — that's not a warning sign, it's physics. The real question is whether you're losing normal amounts or whether something is quietly draining your investment.

A pool dropping a quarter inch on a hot Carolina day is perfectly normal. A pool losing an inch a day has a problem, and that problem compounds: water migrating out of your shell erodes surrounding soil, destabilizes the structure, spikes your chemical costs, and eventually damages your plaster and coping.

In peak summer, an uncovered pool evaporates roughly a quarter to a half inch of water per day. Over a week, that's 1.5 to 3 inches. On a standard 15x30-foot pool, 2 inches of evaporation equals about 560 gallons — considered perfectly normal. Over a full Carolina summer, you're topping off your pool several times over from evaporation alone.

Add splash-out from active swimmers and backwashing your filter (200 to 400 gallons per backwash cycle), and weekly water loss can look alarming even when nothing's wrong. Before you call anyone, run the bucket test.

This is the most reliable way to separate evaporation from a real leak, and it costs nothing but a bucket and a day.

Here's how: Fill a five-gallon bucket three-quarters full of pool water. Set it on a pool step so the bucket water and pool water are at the same temperature. Mark the water level inside the bucket with tape or a grease pencil. Mark the pool water level on the skimmer or wall at the same time. Leave the pump running normally for 24 hours — don't backwash or add water. After 24 hours, compare both drop measurements.

If the pool dropped the same amount as the bucket, evaporation is your answer. If the pool dropped significantly more, you likely have a leak. A quarter-inch gap between bucket and pool is noise. A half-inch or more of unexplained additional drop is worth investigating. An inch or more means call a professional.

Most pool leaks don't announce themselves with dramatic cracks. The common culprits are subtler — and they still cost you money and, over time, structural integrity.

Light fixtures are one of the most frequent offenders. The conduit running through your pool wall behind each light niche is a common leak source. The seal degrades over time, especially in pools that haven't had the lights serviced in years. It drips constantly but slowly.

Skimmer throats are another classic failure point. The joint where the skimmer body meets the concrete shell is prone to cracking and separation after ground movement or years of thermal cycling.

Return fittings — where plumbing connects back through the shell — can loosen or lose sealant integrity over time. A slow drip at a fitting never stops.

Underground plumbing is the scenario no one wants. Tree root intrusion, settling soil, or even the mild freeze events the Carolinas occasionally see can stress buried lines. These are the hardest leaks to locate and the most expensive to fix.

The shell itself — actual cracks in the gunite — is less common than the above but does occur, particularly around steps, main drains, and structural transitions.

If your bucket test points to a real leak, call a leak detection specialist — not a general pool service company. These technicians use pressurized line testing, dye injection, and electronic listening devices to locate water movement around and under your pool.

Expect to pay $200 to $500 for a detection visit. Most residential leaks are located within two to three hours. Repair costs vary: a skimmer reseal runs $200 to $400, a light niche repair is similar, and underground plumbing repair — if excavation is required — ranges from $500 to $2,000 or more depending on depth and access.

Don't delay calling over the repair cost estimate. An unaddressed leak costs more in water, chemical imbalance, and structural damage than the fix itself.

Not all pools leak at the same rates. The quality of the fittings, the care taken in sealing light conduits, and the precision of the plumbing rough-in during construction all determine how long a pool runs before developing water management problems.

A homeowner touring their pool mid-build won't notice whether the light conduit was sealed with marine-grade compound or the bare minimum — but they'll notice the difference in year eight when one pool needs a repair and the other doesn't. Cutting corners on fittings and sealants doesn't show up on day one. It shows up years later.

If your pool is losing more water than usual, run the bucket test before calling anyone. Most water loss scares are evaporation. If the test points to a leak, bring in a specialist rather than watching it get worse.

And if you're still in the planning phase, this is a reason to care who builds your pool. Rock Water Pools constructs custom concrete pools across Lake Norman, Mooresville, and the Carolinas with the attention to plumbing, fittings, and shell work that most homeowners never see — until they don't have a problem. Call us at 704-450-1023 to start a conversation about your project.