Swimming Pool Leak Detection

If you are topping the pool up every day, the water is going somewhere. Every litre that escapes takes your dosed chemicals with it, and on a heated pool it takes paid-for heat too, so the real cost of a pool leak is always bigger than the water bill alone. After more than 30 years finding leaks across Cornwall and Devon, we can tell you the leak is rarely where the wet patch is, and almost never where the guesswork starts.

Our swimming pool leak detection service pinpoints the leak first, whether it is in the liner, the shell or the buried pipework, so any repair is one precise job rather than a season of trial and error. No call-out fees, a fixed price agreed up front, and No Find, No Fee on residential pool leak detection (subject to terms).

💧 Leak or evaporation? The quarter-inch rule

Every pool loses some water to evaporation. Industry guidance from pool specialists such as In The Swim and American Leak Detection puts normal evaporation at around a quarter of an inch (about 6mm) a day, a little more in hot, windy or low-humidity weather. If your pool is dropping faster than that, evaporation is not the explanation. You have a leak.

The quickest way to confirm it at home is the bucket test: a bucket of pool water on the step, levels marked, compared after 24 hours. If the pool level falls further than the bucket level, water is escaping rather than evaporating. We have covered the full method, including the pump-on, pump-off variation that tells you whether the leak is in the plumbing, in our pool leak diagnosis guide, so you can check before you spend a penny.

One thing worth knowing before you reach for the phone: a leaking pool does not fix itself. Escaping water erodes the ground around pipework and undermines pool surrounds, so a small leak left through the season tends to become a bigger repair by autumn.

📍 Where pool leaks happen

Pools leak from a fairly predictable set of weak points: the skimmer where plastic meets concrete, return fittings and their gaskets, the light niche and its conduit, liner seams and punctures, hairline cracks in concrete shells, and the buried suction and return lines between the pool and the plant room. In our experience a large share of the leaks we find sit in that buried pipework rather than in the pool structure itself, which is why a visual once-over so often finds nothing.

We have written up the full tour of weak points, pool type by pool type, in where swimming pools leak. This page sticks to the part you cannot do yourself: pinpointing which of those suspects is actually guilty.

🔍 How we find pool leaks, step by step

Pool leak detection is a process of elimination with the right tools in the right order. We never start by draining the pool or breaking ground, and most surveys finish without either.

🏊 Liner, shell or plumbing: it changes everything

The right detection method depends on where the water is escaping, and the three main pool builds each fail in their own way:

The pipework row is the one that catches pool owners out. Those lines run under the deck and lawn, so the first visible clue is often a soft patch of grass or a crack creeping across the surround. The methods are close cousins of our underground leak detection work, adapted for pool hydraulics, and on heated pools thermal imaging can reveal a warm leak plume without lifting a slab. Where we need to listen rather than look, our acoustic leak detection kit does the searching, and tracer gas detection settles the cases nothing else can.

🏨 Holiday lets, hotels and campsite pools

Cornwall and Devon run on tourism, and a heated pool is often the difference between a booked-out season and an empty calendar. That also means a leaking pool here is a business problem, not just a maintenance niggle. A pool that cannot hold its level safely gets closed, guests notice, and reviews follow.

We work on pools at holiday lets, guest houses, hotels, campsites and holiday parks across both counties, and we plan the work around your bookings: out-of-season surveys before the pool reopens, or quick, low-disruption visits mid-season when a problem appears. Owners get the same fixed pricing, plus documentation that supports an insurance claim where the leak has caused damage. For wider site problems beyond the pool, our commercial leak detection service covers the rest of the property.

If you manage a property remotely, we are happy to liaise with your housekeeper, maintenance contact or pool service company and report back to you directly with photographs and findings.

📋 What to expect, and when to book

A pool leak survey is not disruptive. The pool normally stays full, the garden stays intact, and most of the work happens at the plant room, the fittings and the pipe runs. A few things speed us up:

• Note how much the level drops per day, and whether it differs with the pump running or off
• Keep any pool plans or build drawings handy if you have them, since knowing where the pipes run saves searching time
• Clear access to the plant room, skimmers and the pool surround
• Tell us the pool type (liner, concrete, fibreglass) and roughly when it was built

Timing matters more with pools than with most leaks. Spring opening is when winter damage shows itself, because freeze-thaw cycles crack concrete and shift buried pipes while the pool stands idle. Autumn is the other smart moment: a detection check before winter closing means you shut down a sound pool rather than sealing a leak in for six months. Mid-summer, high evaporation can mask a modest leak, which is exactly why the quarter-inch benchmark and the bucket test are worth knowing.

On the day we test, dye, listen and mark the leak position, then talk you through what we found and the sensible repair route. The price is the one agreed before we arrived.