Is Your Pool Leaking? The Bucket Test and When to Call a Pro

By the BlueIQ Pools team · October 19, 2026

Short answer: every pool loses some water to evaporation, but if your pool drops noticeably faster than a bucket of water sitting on the pool steps, you most likely have a leak. The bucket test takes 24 hours, costs nothing, and tells you whether it is time to call for leak detection.

Evaporation or leak?

Sun, wind, warm water and cool nights all speed up evaporation. On a hot, windy NJ summer day a pool can lose around a quarter inch to evaporation, and heated pools and spas lose more. The problem is that evaporation and a slow leak look the same from the deck - which is why you compare against a bucket that is exposed to exactly the same conditions.

How to do the bucket test

1. Fill a 5-gallon bucket with pool water and set it on the first or second step, so it sits in the pool water at the same temperature.
2. Make the water level inside the bucket match the pool level as closely as you can.
3. Mark the water level inside the bucket and the pool level on the outside of the bucket with tape or a marker.
4. Turn off any auto-fill, and do not add water or let the irrigation splash into the pool during the test.
5. Run the pump on its normal schedule and wait 24 hours.
6. Compare: if the pool level dropped more than the water in the bucket, you are losing water to something other than evaporation.

Tip: repeat the test once with the pump running and once with it off. If the pool loses more with the pump running, the leak is more likely on the pressure side (return lines, equipment after the pump). If it loses more with the pump off, look at the suction side (skimmers, main drain, suction lines).

Other signs of a leak

• You are adding water more than about once a week, or the auto-fill seems to run constantly
• Wet or soggy spots in the yard, or water around the equipment pad
• Cracks or gaps in the deck, tile line or around the skimmer
• Air in the pump basket or bubbles from the returns (often a suction-side leak)
• The water level always stops dropping at the same point - often the skimmer, a light or a fitting at that height
• Chemicals are hard to keep balanced because fresh water keeps being added
• A higher water bill without a clear reason

Where pool leaks usually hide

• Equipment pad - pump seals, filter o-rings, valves, heater connections and unions. These are often the easiest to find and fix.
• Skimmers - the joint between the skimmer and the pool wall moves and cracks over time.
• Light niches - the conduit and seal behind the light are common leak points.
• Return and drain fittings where they pass through the pool wall or floor.
• Underground plumbing - cracked lines, often after freeze damage or settling.
• The pool shell - cracks in plaster or gunite, or tears in a vinyl liner.

Why to find it before closing

A leak in an underground line or fitting can get worse over the winter, when water in damaged plumbing freezes and expands. A pool that keeps losing water under the cover can also drop below the level the cover and skimmer plugs were set for. Finding and fixing a leak before closing usually costs less than dealing with it - and the damage around it - in spring.

What professional leak detection involves

We start by confirming it is a leak and not evaporation, then narrow it down: inspecting the equipment pad, checking skimmers, lights and fittings, pressure testing the plumbing lines and using dye testing at suspected spots. Leaks at the equipment pad and fittings can often be repaired directly; for major underground or structural repairs we give you a clear recommendation and estimate.

Did your bucket test show a leak? Send us the result and how much water you are losing per day, and we will tell you the next step.