Pool leak detection, after you have proved there is a leak

What is pool leak detection & repair?

Pool leak detection is the process of confirming that a pool is losing water beyond normal evaporation, then locating where - the shell, a fitting, the plumbing, or somewhere in the equipment pad. Repair is a separate job that depends entirely on what is found, from a fitting reseal costing very little to excavating a buried line. The first step costs nothing: a bucket test run over a day or two will tell you whether you have a leak at all, and a large share of suspected pool leaks turn out to be evaporation, splash-out or backwash water.

Signs you need pool leak detection & repair

• You are topping up more often than you used to, and the change is not explained by hotter weather or heavier use
• The water settles at a consistent level and stops - which often points at a fitting or a skimmer at that height
• There is a persistently wet or unusually green patch in the yard, or near the equipment pad
• Air keeps appearing in the pump basket or the returns, which can mean a suction-side leak drawing air in
• Your chemical consumption has climbed because you are constantly diluting the pool with fresh water
• Cracks, gaps or movement have appeared at the tile line, around fittings, or in the deck near the pool
• The autofill is running far more than it should, or your water bill has stepped up

Seeing something not on this list? Browse pools problems by symptom →

How pool leak detection & repair actually works

1. 1

   Prove it first - the bucket test

   Stand a bucket of pool water on a step so the levels inside and outside match, mark both, and compare after a day or two with the pump running normally. Both dropping equally means evaporation; the pool dropping faster means a leak.

   Watch forPaying for detection before doing this. It is free, it is definitive, and a company that discourages it before quoting is telling you what kind of company it is.

2. 2

   Narrow it down - plumbing or structure?

   Comparing loss with the pump running against loss with it off is the classic split: faster loss with the pump on points at pressure-side plumbing, faster with it off points elsewhere. Where the level stabilises is another strong clue.

   Watch forA quote to excavate before this narrowing has been done. Digging is the expensive answer and it should be the last one, not the first.

3. 3

   Detection - pressure testing and listening

   Lines are isolated and pressure-tested individually to find which one is failing. Acoustic listening equipment, dye testing at fittings and cracks, and sometimes cameras are used to pinpoint the location.

   Watch forA vague result. You are paying for a location, not for an opinion. Ask what the deliverable is: which line, or which fitting, and where.

4. 4

   Get the finding in writing before agreeing any repair

   Detection and repair are genuinely different services with different skills, and some companies do only one. A written finding lets you get the repair priced by more than one party.

   Watch forA single price covering "find and fix". It removes your ability to compare the repair, and the repair is usually the larger number by a wide margin.

5. 5

   Repair, scoped to what was actually found

   Fitting and skimmer leaks are resealed. Liner punctures are patched. Shell cracks are addressed structurally. Failed lines are either repaired at the point of failure or bypassed with a new run, which is often cheaper than chasing an old line under a deck.

   Watch forCosmetic repair of a structural crack. If the shell is moving, sealing the crack is a delay rather than a fix, and the underlying cause needs a proper opinion.

6. 6

   Verify the fix

   The pool is refilled and monitored, ideally with a repeat bucket test, to confirm the loss has actually stopped rather than reduced.

   Watch forPools with more than one leak. It is common enough that "it is better but not fixed" should be treated as a second leak rather than as a failed repair.

What does pool leak detection & repair cost?

Detection is usually a fixed call-out and investigation fee. Repair is separate and spans from a very small fitting reseal to excavating and replacing a buried line under a deck. Insist on the two being quoted separately - the gap between them can be a hundredfold.

See the full pool leak detection & repair cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →

Volume calculators → Working out how much water you are losing.