Is My Pool Leaking? How to Tell and What To Do

You notice the water level dropping. The autofill seems to run more than it used to. Maybe you’re adding water manually more often than feels normal. The question every pool owner eventually asks: is my pool leaking, or is this just evaporation?

In Phoenix, the answer isn’t always obvious. The desert climate causes significant water loss from evaporation alone. But understanding the difference — and knowing what to do if it is a leak — can save you from wasting thousands of gallons and potentially damaging your property.

Normal Evaporation in Phoenix

Before assuming you have a leak, understand what normal water loss looks like:

Summer (May–September): 1/4 to 1/2 inch per day is normal. During extreme heat weeks with low humidity and wind, losses near the upper end are expected.
Winter (October–April): 1/8 to 1/4 inch per day. Cooler temperatures and shorter days reduce evaporation significantly.

Factors that increase evaporation:

Wind exposure (no screen enclosure or windbreak)
Full sun — no shade structures
Water features running (waterfalls, fountains, bubblers dramatically increase surface area and evaporation rate)
Heated pools lose water faster than unheated ones

If your pool is losing water within these ranges, you probably don’t have a leak. If it’s losing more — especially consistently — it’s time to investigate.

Signs That Point to a Leak

Beyond just the water level, watch for these indicators:

Autofill running constantly — If you hear your autofill valve cycling frequently or your water bill has increased without explanation, something is off.
Wet or soft spots in the yard — Especially near the pool, equipment pad, or along plumbing runs. An underground pipe leak will saturate the surrounding soil.
Cracks in the deck that are worsening — Soil erosion from a leak can cause concrete to settle and crack.
Air bubbles in return jets — Air being pulled into the plumbing suggests a suction-side leak.
Algae growth despite proper chemical levels — A leak introduces fresh, untreated water that dilutes chlorine and destabilizes chemistry.
Equipment losing prime — The pump strainer basket not staying full can indicate a plumbing leak on the suction side.

The Bucket Test

The bucket test is the standard DIY method for distinguishing evaporation from a leak:

Fill a 5-gallon bucket with pool water and place it on the top step of the pool, submerged so the water levels inside and outside the bucket are close to the same temperature.
Mark the water level on the inside of the bucket (bucket water) and on the outside of the bucket (pool water level).
Wait 24 hours with the pump running on its normal schedule. Don’t use the pool during this time.
Compare the levels. If the pool water dropped more than the bucket water, the pool is losing water beyond evaporation — you have a leak.

For more precision, repeat the test with the pump off for 24 hours. If the leak rate changes between pump-on and pump-off, it helps narrow the leak location:

More water loss with the pump on — suggests a pressure-side (return) leak
More water loss with the pump off — suggests a suction-side or structural leak
Same rate regardless — suggests a shell or fitting leak

Where Pools Typically Leak

The most common leak locations, in order of frequency:

Equipment pad plumbing — Unions, valves, and fittings at the pump, filter, heater, and chlorinator develop leaks over time from vibration, thermal cycling, and chemical exposure.
Underground plumbing — PVC pipe runs between the pool and equipment can crack from ground movement, root intrusion, or age.
Skimmer — The joint between the skimmer body and the pool shell is a common failure point, especially on older pools.
Light niche and conduit — The conduit pipe behind the pool light and the seal around the light niche are frequent leak sources.
Return and suction fittings — Wall fittings can crack or lose their seal with the pool shell.
Main drain — Less common but possible, especially on older pools with original plumbing.
Pool shell — Structural cracks in plaster or gunite. This is actually the least common source but the most feared.

What to Do if You Suspect a Leak

Step 1: Confirm with the Bucket Test

Don’t call a professional based on a feeling. Run the bucket test first. It costs nothing and gives you a factual baseline.

Step 2: Check the Equipment Pad

Walk the equipment pad carefully. Look for:

Drips at unions, valves, or connections
Wet ground around the equipment
Corrosion stains on fittings (indicates slow, chronic drips)

Equipment pad leaks are the easiest and cheapest to repair.

Step 3: Call a Professional for Leak Detection

If the bucket test confirms a leak and the equipment pad looks dry, the leak is likely underground or in the pool structure. Professional leak detection uses:

Pressure testing of individual plumbing lines
Electronic listening equipment to detect water escaping through pipe walls underground
Dye testing at suspected locations (fittings, cracks, skimmers)

A professional can typically pinpoint a leak’s location without excavation. The repair may require digging, but the detection itself is non-invasive.

Step 4: Repair Promptly

A pool leak doesn’t fix itself, and it gets worse over time. Beyond wasted water and chemicals, a persistent leak can:

Erode soil around the pool, undermining the deck and pool structure
Damage landscaping and hardscape
Compromise the pool’s structural integrity

Think your pool might be leaking? Contact Splash Mob Pools for professional leak detection in the Phoenix metro area. We’ll find it and fix it.