Pool and spa leak detection in the Phoenix valley

The pool is down again. You topped it up on Sunday and by Thursday the tile line has moved. The first question is not where the leak is — it is whether there is one at all, because in a Phoenix summer a perfectly sound pool loses a startling amount of water to the sky.

Evaporation first, always

Scottsdale Water publishes month-by-month evaporation figures for an open pool. Worked out per day, June comes to more than a third of an inch and July is barely behind it, which means a sound pool sails past the old quarter-inch-a-day rule of thumb every single summer. So the number is not the test. The bucket test is: a bucket of water standing on a pool step, in the same sun and the same wind, marked inside and out. Same drop in both, that is evaporation. Pool drops further, something is losing water.

Then run it a second time with the pump off. If more water goes missing while the equipment runs, attention moves to the plumbing. If the loss is identical either way, it is the structure, the fittings or the skimmer. That one answer decides half the visit, and you can hand it to us before we arrive.

Where Valley pools actually lose water

Skimmer throat

The most common single find. The skimmer is a plastic or concrete box cast into a shell that moves with the ground around it; the joint between the throat and the gunite separates and water leaves at the waterline. It is also the one that most often explains a pool that stops dropping once the level falls below the skimmer mouth.

Shell, plaster and the tile line

Hairline cracks in plaster, a popped-out tile, a separation at a step or a bench. Small, slow, and not visible to a casual look — this is where dye earns its keep, with the pump off and the water dead still, watching whether the dye is drawn in.

Light niche and conduit

A niche leaks either at the niche-to-shell joint or through the conduit that carries the light cord back to the junction box, in which case the pool is quietly feeding a buried pipe. It is easy to miss because the water level often stabilises just below the light.

Returns, suction lines and the equipment pad

Buried PVC under a deck, pressure-tested line by line. Before any of that we look at the pad itself: a weeping pump seal, a filter clamp, a backwash valve that never seated and a heater bypass have all been mistaken for a pool leak, and none of them needs the deck opened.

How the leak is located, and what that cannot do

Each line is isolated with plugs and put under pressure on a gauge, so it either holds or it does not. A line that fails the gauge is then listened to through the deck to turn “this line” into a spot. Dye handles the shell. The honest limits are worth knowing: dye needs still water, so a windy afternoon or a running pump ruins it; listening through wet coping and saturated soil can put the loudest point a little off the break; and a pool with two leaks will hide the smaller one behind the bigger until the first is fixed. We say so when that happens rather than call the job finished.

After it is found

You get shown the spot first. Most of what we locate we also repair — see pool and spa leak repair — and the opening is only as big as the fix requires. A skimmer or a shell repair is usually a small, contained job. A failed return line under a deck is sometimes better rerouted than chased.

When it is not a pool leak

Splash-out from a busy weekend, a backwash line left cracked open, an auto-fill valve stuck down, a water feature plumbed to run when the pump does, or an irrigation line running under the deck and soaking the same area. If your bill is the thing that changed and the pool level looks normal, start at the bill instead.