Pool Losing Water? Leak or Evaporation and the Bucket Test
Most uncovered Florida pools lose some water to evaporation every day. A bucket test, which costs nothing, tells you whether yours is losing more than that.
Symptoms
Signs the water loss is a leak
- The level drops faster than the ⅛ to ¼ inch a day a Florida water management district gives for evaporation from an uncovered pool.
- After a bucket test, the pool's level is lower than the bucket's.
- Bubbles come out of the return fittings on the pool wall, which a pump maker links to air leaks on the suction side.
- The pump loses its prime as the level drops.
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A pool losing water is evaporating, leaking, or both. The Southwest Florida Water Management District says “most uncovered pools in Florida will lose about ⅛” to ¼” of water a day to evaporation depending on what type of water features, such as waterfalls or fountains, are present.” That is roughly ⅞ inch to 1¾ inches a week. So a pool losing about an inch a week may be doing nothing more than evaporating, and a pool losing half an inch a day is losing more than the district’s evaporation figure.
How to run the bucket test
The bucket test compares the pool’s water level with a bucket’s. The water management district gives it in three steps:
- Place a bucket filled “with enough water so that the level of water is equal to the level in the pool.”
- “Without using the pool, check the water levels in a few days.”
- “If the pool’s water level is lower than the bucket’s water level, your pool may have a leak.”
If both have dropped by about the same amount, that points to evaporation; if the pool has dropped more, it may have a leak.
Reading the result
A leak shows up as a pool level below the bucket’s. Before you call anyone, check the pool’s automatic fill valve: the district says to make sure it is not “malfunctioning and causing a continuous cycle of water to be pumped in and then drained out.” Then note how much the pool lost compared with the bucket, and whether it loses more with the pump running or off, and pass that on when you book.
Where pools leak
The EPA says “common leak locations include pump seals, pipe joints, piping in filtration system suction or return lines”. A pump maker, Hayward, adds a clue you can see: air leaks on the suction side “will result in bubbles emanating from the return fittings on the pool wall.” Cracks in the plaster or shell are the other place to look; surface crazing or a structural crack explains how far you can tell from the deck.
When to book leak detection
Book it when the bucket test shows the pool dropping faster than the bucket. A leak search uses pressure tests on the plumbing and dye at suspect spots; pool leak detection explains each test and what the repair involves. A maker of leak detection equipment is plain about dye: it “confirms a leak at a spot you already suspect.” The bucket test is what tells you a search is worth booking.
Causes
Where the water goes
Some loss is evaporation: a Florida water management district says most uncovered pools in Florida lose about ⅛ to ¼ inch a day. A bucket test tells the two apart. When it is a leak, the EPA lists pump seals, pipe joints and the suction and return lines as common places.
- Evaporation: most uncovered pools in Florida lose about ⅛ to ¼ inch a day, depending on water features such as waterfalls or fountains (Southwest Florida Water Management District).
- A leak in the plumbing or at the pump: the EPA lists pump seals, pipe joints and the suction and return lines as common leak locations.
- A crack in the plaster or the shell: a Florida plaster maker says a surface crack and a structural crack cannot be told apart without draining the pool and cutting a sample.
- An automatic fill valve that is not working: the same water management district says to check that it is not pumping water in and then draining it out.
Urgency
How soon it needs attention
Keep the water topped up while you find out. Pentair's pump manual says that if the level falls below the suction port, the pump draws air, loses its prime and runs dry, "resulting in a damaged seal".
The fix
What finds and fixes the leak
Leak Detection and Repair
Finding where a pool is losing water, from the pump seals and pipe joints to the suction and return lines, and repairing the leak once it is found.
Pool Pump Repair
Repair or replacement of a pool pump that hums but will not start, will not prime, leaks at the seal or trips the breaker.
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Questions, answered
Frequently asked questions
How much water does a Florida pool lose to evaporation?
The Southwest Florida Water Management District says most uncovered pools in Florida lose about ⅛ to ¼ inch of water a day to evaporation, depending on water features such as waterfalls or fountains. That works out to roughly ⅞ inch to 1¾ inches a week.
How do I do a bucket test?
Fill a bucket so the water inside is level with the water in the pool, and leave the pool unused. Check both levels in a few days. If the pool's level is lower than the bucket's, the pool may have a leak. Those steps come from the Southwest Florida Water Management District.
Is it normal to lose 1/2 inch of water a day in a pool?
Half an inch a day is more than the ⅛ to ¼ inch a day the Southwest Florida Water Management District gives for evaporation from most uncovered Florida pools. Water features such as waterfalls or fountains change the figure, so run a bucket test before deciding it is a leak.
Get a Free Pool Repair Quote
Tell us what is wrong with your pool, and a licensed local pool pro gets in touch about a free written quote.