You top off the pool on Saturday, and by Wednesday, the water line has slipped below the tile again. Maybe the auto-fill seems to run more than it used to, or the water bill came in higher than last month. In South Florida, the sun draws water from every pool, so the real question is whether you're seeing evaporation or a leak that needs pool leak repair.
The good news is that you can figure out a lot on your own before you call anyone. Start with how much water you're actually losing, then work through the spots where gunite pools tend to leak.
Is My Pool Leaking or Just Evaporating?
Some water loss is normal, especially with waterfalls and fountains running. What you're watching for is loss that evaporation can't explain, week after week.
The U.S. Environmental Protection Agency puts a weekly number on it. Its WaterSense pool guide says a pool losing more than 2 inches a week, or 3 inches in hot, dry areas with high evaporation rates, likely has a leak. One hot, windy week in August can stretch the normal range. A steady pattern is what you're looking for.
What Are the Signs of a Pool Leak?
Water loss is the main clue, but a leaking pool usually leaves other evidence behind. Some of it shows up in the pool itself:
- The water level drops more than 2 inches a week with no rain, heavy splashing, or backwashing
- Air bubbles in the pump basket or coming out of the return jets
- Cracks in the plaster or tiles that are loose or falling off
- Algae that keeps coming back, even when you balance the chemicals
Other signs show up around the yard and equipment:
- Soggy grass or wet spots near the pool or along the plumbing route
- Water pooling under or around the pump, filter, or heater
- An auto-fill that seems to run constantly, or a water bill that keeps climbing
- Deck pavers or concrete that are sinking or shifting
How Do You Do a Bucket Test on a Pool?
A bucket test compares the water your pool loses with the water a bucket loses under the same sun and wind. Both evaporate at about the same rate, so any extra loss from the pool points to a leak. The WaterSense guide lays out the method:
- Pick a day with no rain or heavy wind, and shut off all pool systems, including the auto-fill, for 24 hours.
- Fill a 2.5- to 5-gallon bucket with water to about 1 inch from the top.
- Set the bucket on a pool step or bench so at least two-thirds of it sits underwater.
- Mark the water level inside the bucket and the pool's water level on the outside of the bucket.
- After 24 hours, compare the two. If the pool dropped more than the bucket, you may have a leak.
Turn Off the Auto-Fill First
An auto-fill is a valve that tops off your pool from your home's water line whenever the level drops. It's convenient, and it's also why plenty of South Florida leaks go unnoticed for months. The pool never looks low, so the only clue is the water bill. The same guide suggests turning off auto-fill for 24 hours every three months to check for leaks, which takes almost no effort.
Does Your Pool Lose More Water With the Pump On or Off?
Running the bucket test twice, once with the pump off and once with it running, tells you which part of the plumbing to suspect. For the second run, leave the pump on and keep the auto-fill off. Your pool's circulation has two sides. The suction side pulls water out through the skimmer and main drain, and the pressure side pushes filtered water back through the return jets.
- More loss with the pump on: the leak is likely on the pressure side, in the return lines or the equipment after the pump.
- More loss with the pump off: the suction side is the likely culprit, usually the skimmer or main drain lines.
- Same loss either way: look at the shell, the light, or a fitting set into the pool wall.
Watch where the water stops, too. If the level drops and then holds steady at one spot, check whatever sits at that line: the skimmer, a light, a return fitting, or a crack.
Where Do Gunite Pools Leak?
On a gunite pool, leaks usually start where something meets the concrete shell: fittings, joints, and openings for pipes and lights. The EPA lists the pump seal, pool piping, the pool-to-pipe connection, pool edges, and pipe joints as common leak points.
The Skimmer
The skimmer is the box set into the pool wall at the waterline, and the joint where it meets the gunite is a frequent trouble spot. Ground movement and a shifting deck can open a small gap between the two. Look for cracks around the skimmer opening and where the deck meets the skimmer lid.
The Light Niche
Your pool light sits in a housing called a niche, with a conduit running back to the electrical box. Leaks happen around the seal or where the conduit enters the niche. If the water level stops dropping right at the bottom of the light, start here. Old lights and their seals tend to wear out together, which is one reason homeowners often look at new in-ground pool lights during a repair.
Return Lines and Wall Fittings
Returns are the jets that push filtered water back into the pool. Their fittings can loosen over time, and the underground lines can crack, especially in older pools or where tree roots grow near the plumbing. Leaks here usually get worse when the pump is running.
The Main Drain and Hydrostatic Valve
The main drain sits at the deepest point of the pool. Many Florida gunite pools also have a hydrostatic relief valve, a valve in the floor that lets groundwater in to relieve pressure under the shell. If that valve's seal or the drain fittings fail, pool water can escape through the floor. Both are hard to check without diving, so they're usually the last spots you can inspect on your own.
The Tile Line and Shell Cracks
Check the tile band and the joint where the coping meets the pool for gaps, loose tiles, or cracks. Hairline cracks in the plaster are often cosmetic. A crack that runs into the gunite itself, or one with rust stains from the steel inside, needs a professional look. Grab a mask and do a slow lap, since many cracks are easier to spot underwater.
The Equipment Pad
Walk out to the pump, filter, and heater and look for drips, damp concrete, or crusty white deposits around the unions and valves. Pump seals and O-rings wear out over time. A dripping seal is a common reason for swimming pool pump repairs, and usually one of the quicker fixes.
How Does a Dye Test Pinpoint a Leak?
A dye test uses a small squirt of colored dye to show where water is moving. Once you have a suspect spot, turn off the pump so the water is completely still. Then release a little pool leak dye right next to the crack or fitting. If the dye drifts away, that spot is fine, but if it gets pulled into the gap, you've found your leak.
Use dye made for pools, and get as close to the surface as you can without touching it. Dye testing works well on cracks, the skimmer, light niches, and return fittings you can reach. It can't show you what's happening in pipes buried under the deck.
Why Shouldn't You Drain Your Pool to Find a Leak in South Florida?
Draining a gunite pool in South Florida is risky, and it rarely helps you find a leak anyway. Much of the region has a high water table, which means groundwater sits close to the surface and pushes up on the bottom of the pool. The weight of the pool water holds the shell in place. Take that weight away, and the pressure can crack the floor or even lift the shell.
Florida treats draining a pool for repair as licensed work. Under Florida Statute 489.105, a licensed pool contractor's scope includes "the substantial or complete draining of a swimming pool" for repair or renovation. Professionals find most leaks with the water still in. If your pool ever needs draining for resurfacing, a licensed contractor should check groundwater conditions first.
When Should You Call a Pro for Pool Leak Repair?
Call a professional once you've confirmed a leak but can't find it, or as soon as the signs point to underground plumbing, the main drain, or a structural crack. Leak technicians use pressure testing, which seals off each plumbing line to see whether it holds pressure. They also use listening equipment that picks up water escaping underground, so nobody has to tear up your deck to guess.
The same Florida statute places repair of pool piping within a licensed pool contractor's scope. Before you hire anyone, ask for their license number and look it up on the Florida Department of Business and Professional Regulation (DBPR) website, which lets you verify a license by name or number. Fountain Blue Pools holds license CPC 1458668 and has served South Florida since 1996. Our service team handles pool and spa leak detection and repairs across Palm Beach County and the Treasure Coast.
Pool Leak FAQ
How much water does a pool lose to evaporation in Florida?
It varies with heat and wind, but the EPA estimates an uncovered 500-square-foot pool can lose 12,000 to 31,000 gallons a year to evaporation. Water features push that number higher. A pool cover can cut evaporation losses by 70% or more, according to the South Florida Water Management District.
Can you fix a pool leak without draining the pool?
Yes, most pool leaks are found and repaired with the water still in. Fittings, skimmer joints, light niches, and small cracks can be sealed underwater, and plumbing leaks are repaired from outside the pool. Draining is usually saved for resurfacing or major structural work.
Where is the most common place for a pool leak?
On a gunite pool, the most common leak spots are the skimmer, the light niche, the return fittings, and the equipment pad. These are all places where plastic, metal, or pipe meets the concrete shell. Check them before you suspect the shell itself.
How much does it cost to repair a pool leak?
The cost depends on where the leak is and how hard it is to reach. Replacing an O-ring at the equipment pad is a small job, while a cracked line under the deck takes a lot more work. This breakdown of pool repair costs in South Florida covers what drives the price.
How long does a gunite pool last?
A well-maintained gunite pool can last a lifetime. The surface, whether plaster, quartz, or pebble, typically needs resurfacing every 10 to 15 years. Catching leaks early protects both the shell and the soil underneath it.
Get Your Water Line Back Where It Belongs
If your bucket test says leak, or you'd just like a second set of eyes, call the Fountain Blue Pools service department at 561-969-2299 ext. 3. We've been keeping South Florida pools full and swimmable since 1996, and we'll track down the source so you can go back to enjoying the water instead of watching it disappear.
