Do a bucket test next to the skimmer before you assume the worst. Owners of fiberglass pools in Pasco County, Hernando, Citrus, Hillsborough, and Pinellas see the same question every dry front: is it a leak, or is it evaporation? Florida pools lose water to sun, wind, and dry air — and they also get real leaks. The bucket test separates the two in about a day. And if there is a leak, the water will always find it: the level drops to the height of the leak within a few days and then tends to hold there.
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Why the waterline drops in Florida
Evaporation speeds up when the air is cooler and drier than the water, or when wind strips moisture off the surface. That pattern shows up often in Tampa Bay fall and winter fronts — from Port Richey and Trinity to Clearwater, St. Petersburg, and Brandon — the water can still feel warm while the night air does not. Service companies across the region publish seasonal notes on fall water loss; treat those as context, then prove it on your own pool with a bucket test rather than guessing from a single overnight drop.
Splashing, backwashing the filter, and a stuck auto-fill can also move the waterline. Rule those out, then test.
How to run a bucket test next to the skimmer
- Pick a calm stretch — avoid testing during a party day or heavy rain forecast. Twenty-four hours is the usual window; forty-eight is even clearer.
- Fill a clean bucket with water from the pool (not the hose), and set it on a step or ledge next to the skimmer so the bucket and the pool share the same sun and wind.
- Mark two waterlines: one on the inside of the bucket, and one on the pool tile or a piece of tape on the skimmer face, at the current pool level.
- Turn off auto-fill devices for the test so they do not mask a drop.
- After 24 hours, compare. If the pool and the bucket dropped about the same, you are mostly seeing evaporation. If the pool dropped clearly more than the bucket, suspect a leak.
- Optional second day: repeat with the pump off (or on a different schedule) if you are trying to narrow whether the loss is in the shell/fittings or in the underground suction/return lines. A leak-detection tech can finish that diagnosis.
Keep the water near mid-skimmer during normal operation so the pump does not suck air. If the level is crashing overnight, stop and test — do not keep adding water blindly.
Water drops to the level of the leak
When there is a leak, water always finds it. Over a few days the waterline falls until it reaches the elevation of the opening — a crack at a fitting, a skimmer throat, a light niche, a return, or damaged plumbing at that height — and then the drop often slows or stops. That resting level is useful information for you and for a leak-detection tech. Take a photo of where it stabilized before you refill.
What not to do
- Do not drain the pool to “find” a leak. An empty fiberglass shell can float or crack when groundwater pushes up. See our guidance on high water tables and never-drain practice in related install articles.
- Do not ignore a fast drop that fails the bucket test — small leaks grow, and dry shell exposure above the waterline is hard on finishes.
- Do not assume every fall drop is a leak — run the bucket test first.
If you need service on a Pettit pool, start at contact or call. For buying context, see fiberglass vs. concrete and our warranty. New pool shoppers: cost guide and financing Starting at $400 a month W.A.C. — financing.
Leak vs. evaporation FAQs
How do I tell a pool leak from evaporation?
Run a bucket test next to the skimmer. Fill a bucket with pool water, mark the waterline on the bucket and on the pool (tile or tape), and compare after 24 hours. If the pool drops more than the bucket, suspect a leak.
Where should I put the bucket?
Next to the skimmer, on a pool step or ledge, so both the bucket and the pool see the same sun, wind, and air. Use pool water in the bucket, not hose water.
What does it mean if the water stops dropping at a certain level?
Water finds the leak. The level will drop to the height of the leak within a few days and then tend to hold there. That height is a clue — skimmer throat, light niche, return, or a fitting at that elevation.
Does Florida weather make evaporation worse in fall?
Cool, dry, windy fronts can increase evaporation even when the water still feels warm. Local service companies in the Tampa Bay area publish seasonal explainers on fall water loss; always confirm with a bucket test before assuming a leak.
Should I drain the pool to look for a leak?
No. Never drain a fiberglass pool to diagnose a leak without professional guidance — groundwater can float or stress an empty shell. Call for leak detection or service instead.
Need a second set of eyes?
Fiberglass pool installation across Pasco, Hernando, Citrus, Hillsborough and Pinellas — including Tampa, Trinity, Clearwater, and St. Petersburg. Citrus County homeowners in Inverness, Crystal River, Homosassa, and Beverly Hills are welcome too. See our service areas hub for every city we cover from Port Richey.
Call 727-847-7665 or contact us online. Pettit Fiberglass Pools, 6651 Industrial Ave, Port Richey, FL.