Signs Your Pool Is Leaking

Evaporation first

Sun, wind, low humidity and warm water all draw water out of a pool. In a Cape Town summer, with the south-easter blowing, evaporation can be surprisingly high, and splashing and backwashing add to it. That is why a falling level on its own does not prove a leak.

The useful question is whether the loss is consistent with the weather. If the level falls just as fast on a cool, still, overcast week, or with a cover on, something else is going on.

Warning signs worth taking seriously

You top up much more often than you did in past summers.
The level drops overnight or when the pool is covered.
Wet, soft or unusually green patches in the lawn near the pool or the pipes.
Paving or coping that has settled, dipped or lifted.
Damp on a wall below the pool, on sloping or terraced sites.
Water around the pump, filter or valves in the pump room.
Air bubbles in the pump lid, or a pump that loses prime.
Cracks at the skimmer, steps, light or waterline tiles.
The water bill has gone up and nothing else has changed.
Chemicals and algae become harder to control, because fresh top-up water keeps diluting the balance.

How to run a bucket test

The bucket test compares your pool with a bucket of water exposed to the same weather. It is simple and reliable, and leak detection contractors use it too.

Bring the pool to its normal level.
Fill a bucket with pool water to about 10 cm from the top and stand it on the first or second step, so the bucket is partly submerged.
Mark the water level inside the bucket, and mark the pool level on the outside of the bucket.
Run the pump as normal and leave it for 24 hours, without swimming or topping up.
Compare the two drops. If the pool has dropped noticeably more than the water in the bucket, the pool is losing water to something other than evaporation.
Repeat the test with the pump switched off. If the pool loses less with the pump off, the leak is probably in the pressure-side plumbing. If it loses the same, look at the shell, fittings and suction side.

Where pools usually leak

Most leaks are not in the middle of a wall. They are at joints and fittings: the skimmer throat, where it meets the shell; around lights and their cable conduits; at return fittings and the main drain; and at pipe joints underground or in the pump room. Steps and corners on older pools, and the seal behind waterline tiles, are other common spots.

Ground conditions affect how a leak shows itself. In the sandy, low-lying suburbs along the Table Bay coast, escaping water drains away and the first sign may be settling paving. See pool leak detection in Table View. In clay ground, as in parts of Durbanville, water lingers and shows as soft or green patches; see pool leak detection in Durbanville. On sloping sites such as Hout Bay, look for damp walls below the pool; see pool leak detection in Hout Bay.

What not to do

Do not drain the pool to look for the leak. An empty pool can be damaged, and in areas with a high water table it can be pushed upward by groundwater. Most leaks are found with the pool full.

Do not lift paving or open the ground on a guess. Leak detection finds the spot so any opening is small. And do not keep topping up indefinitely: escaping water can wash out soil under paving and, over time, undermine the area around the pool.

What a leak detection contractor does

A contractor will usually confirm the loss with their own bucket test, then use dye at fittings and cracks to see where water is drawn out. Pressure testing isolates each pipe run, and some contractors use listening equipment to trace a leak along a buried pipe. The result should be a clear finding and a repair proposal. Our pool leak detection page explains the process, and the guide to what moves a pool repair quote covers cost factors.

Water use and the City

Cape Town went through a severe drought in 2017 and 2018, and the City has restricted pool filling and topping up in the past. A leak wastes water you may be asked to save. Check the City's current water rules before refilling, and use a pool cover to cut evaporation.

Frequently asked questions

How much water loss means my pool is leaking?

There is no single number. The bucket test compares your pool with evaporation under the same conditions, which is far more reliable than a rule of thumb.

Can I find the leak myself?

You can run a bucket test and look for obvious signs. Pinpointing a leak in a fitting or buried pipe usually needs dye and pressure testing by a contractor.

Is a pool leak an emergency?

Rarely an immediate danger, but escaping water can damage paving, walls and the ground around the pool. Act within days, not months.

Signs your pool is leaking, and how to check