Is my pool leaking or just evaporating?

Pool research sources put normal evaporation anywhere from a couple of millimeters to about 2 inches a week. On hot days, about a quarter inch a day is common.

The amount depends on the weather and your pool:

• Sun and heat. Warm water in full sun evaporates faster.
• Wind. Breezy days pull more water off the surface.
• Humidity. Humid air slows evaporation, while dry winter air can speed it up.
• Heaters and water features. A heated pool, spa spillover or waterfall loses more.
• Swimmers. Splashing and kids jumping in add to the loss.

In Southwest Florida, a screened lanai can cut wind and shade the water a little. Summer rain can also hide water loss, since storms refill the pool. That is why some leaks only get noticed in the dry season.

Put a bucket of pool water on a step so it sits at the same temperature as the pool, mark both levels, and compare after a day or more. Here is how:

1. Turn off the auto-fill if you have one, and do not add water during the test.
2. Bring the pool to its normal level.
3. Fill a bucket about two-thirds full with pool water.
4. Set it on the first or second step so it is partly underwater. It should sit flat and not move. Weigh it down with a few rocks if needed.
5. Mark the water level inside the bucket with tape or a marker.
6. Mark the pool level on the outside of the bucket.
7. Wait at least 24 hours. Pick a stretch with no rain in the forecast. A few days gives a clearer answer.
8. Compare the two drops.

If it rains or gets very windy during the test, start over. Rain is the most common thing that ruins a bucket test in Florida.

If the pool level drops more than the bucket level, you probably have a leak. If both drop about the same, the loss is evaporation.

A small difference can just be measuring error. A clear difference, especially one that shows up again when you repeat the test, is worth taking seriously.

A helpful extra step is to run the test twice, once with the pump running and once with it off. If the pool loses more with the pump on, the leak is likely somewhere in the plumbing. That kind of clue helps a technician narrow down where to look.

Losing more than normal evaporation, week after week, is the main sign. Other clues help confirm it:

• You keep adding water, or the auto-fill runs all the time.
• Your water bill went up with no other explanation.
• Wet or soggy spots in the yard near the pool or equipment, even when it has not rained.
• Cracks in the deck or pool shell, or tiles coming loose.
• Water around the pump, filter or valves.
• Air bubbles coming out of the return jets, or a pump that loses its prime.
• Algae that keeps coming back because fresh water keeps diluting the chlorine.
• The water level stops dropping at one spot, like a skimmer or light.

Most leaks show up at fittings and openings, not in the middle of the floor. Common spots include:

• Around the skimmer, where it meets the pool wall.
• Around pool lights and their conduit.
• At return jets and main drains.
• Underground plumbing lines between the pool and the equipment.
• At the pump, filter and valves on the equipment pad.
• Cracks in the shell or tile line.

Some of these you can check yourself by looking for drips at the equipment. Underground lines and the shell usually need pressure testing and listening equipment to find.

You can narrow it down, but pinpointing most leaks takes special tools. A few safe checks are worth doing first.

• Walk around the equipment pad with the pump on and look for drips, wet spots or spraying fittings.
• Let the water drop for a few days without topping off. If it stops at the same spot every time, the leak is often near that level, like the skimmer or a light.
• Look closely at the skimmer throat and around light niches for cracks or gaps.
• Check the yard between the pool and the equipment for soft or soggy ground on dry days.

Do not dig, cut into plumbing or open pool lights yourself. Lights carry electricity, and underground lines are easy to damage. Leaks in buried pipes or under the shell usually need pressure testing to find.

Have it found and fixed soon. A small leak gets more expensive the longer it runs, and water moving under a deck or pool shell can cause bigger problems over time.

Write down your bucket test results and how much water you add each week. That gives a technician a head start. Total Pool Services handles leak detection and repair, and if the leak turns out to be at the pump or filter, our equipment repair team can take care of it.