Start with the bucket test: set a bucket of pool water on the pool step, mark both water levels, and compare after 24 hours. If the pool drops more than the bucket, it's leaking. Compare the loss with the pump on and off to narrow it to the plumbing or the shell, then use dye near skimmers, returns, lights and cracks to find the exact spot.
If you’re adding water every few days, the first question is simple: is the pool leaking, or is it just evaporating? Here’s how to answer that, then narrow down where the leak is.
Signs your pool is leaking
- You top up the water more than once or twice a week
- The water level stops at the same point every time, often a fitting, light or the skimmer
- Wet or soft spots in the yard near the pool or equipment pad
- Cracks in the shell, tile line or deck
- Loose tiles
- Algae coming back soon after treatment, as fresh water dilutes the chemicals
- Air in the system or the pump losing prime
Step 1: The bucket test
- Fill a bucket with pool water to about 1 inch from the top.
- Set it on the pool’s first or second step so it sits in the pool water and matches its temperature.
- Turn off any automatic refill.
- Mark the water level inside the bucket and the pool level on the outside of the bucket.
- Run the pump on its normal schedule and wait 24 hours.
- Compare the two drops.
| Result | What it means |
|---|---|
| Pool drops about the same as the bucket | Evaporation. No leak. |
| Pool drops more than the bucket | The pool is leaking. |
Step 2: Pump on vs. pump off
Repeat the bucket test twice: once with the pump off for 24 hours, and once with it running for 24 hours.
| Loss is greater… | Likely location |
|---|---|
| With the pump on | Pressure side: return lines or equipment after the pump |
| With the pump off | Suction side: skimmer or main drain lines, or the shell |
| The same either way | Most likely the shell, a light niche or a fitting |
Also watch where the level stops dropping. If it stops just below the skimmer, the skimmer is a prime suspect. If it stops at the light, check the light niche.
Step 3: The dye test
With the pump off and the water still:
- Put on goggles and get in the pool, or work from the deck for shallow spots.
- Squeeze a small amount of leak-detection dye, or food coloring, near a suspected spot: a crack, a fitting, the skimmer throat, a return, a light niche.
- Watch the dye. If it’s pulled into the spot, you’ve found a leak.
Test every fitting, not just the first one that looks suspicious. Pools often have more than one leak.
Step 4: Check the equipment pad
Look for drips or wet areas at the pump, filter, heater, valves and unions. A leak at the pad is the easiest kind to fix.
When you need professional pool leak detection
The bucket and dye tests find many shell and fitting leaks, but not leaks in buried plumbing. If the pump test points to the lines, a professional will:
- pressure-test each line (returns, skimmers, main drain) one at a time,
- listen underwater with a hydrophone for the sound of water being pulled through a crack, and
- listen along buried lines with acoustic equipment to pinpoint an underground break.
Indiana’s freeze–thaw winters are hard on pools. Lines, skimmer throats and fittings that weren’t fully winterized can crack, and the leak only shows after opening in spring.
Get your pool leak found
For pools and spas in Bargersville and the rest of Johnson County, our pool & spa leak detection service tests every line and fitting, then marks the leak so the repair is quick and targeted.
Still can’t find it?
Our pool & spa leak detection pinpoints the leak without tearing things up, so the repair starts in the right spot.
Frequently asked questions
How much water loss is normal for a pool?
It depends on the weather. Hot, dry, windy days can evaporate roughly a quarter inch a day, and mild days much less. The bucket test compares your pool with the same water in the same conditions, so it tells you whether the loss is more than evaporation.
How do I know if the leak is in the plumbing or the pool itself?
Compare the water loss over 24 hours with the pump running and with it off. More loss with the pump on points to the pressure side (return lines). More loss with it off, or the same either way, points to the suction side or the shell.
Where do pools leak most often?
At skimmers, return fittings, main drains, light niches, cracks in the shell or tile line, and the underground plumbing lines between the pool and the equipment pad.
Should the pool be full for leak detection?
Yes. Keep the pool at its normal operating level and the equipment working so every line can be tested.