How to detect a leak in pool

A sudden drop in pool water level can be frustrating but is it evaporation or an actual leak? Detecting a leak early can prevent costly repairs and water loss. Whether you own an inground or above ground pool, this guide will walk you through proven methods to detect a pool leak at home.

Is It a Leak or Just Evaporation?

In warm weather, it's normal to lose some water to evaporation. But if you’re losing more than ½ inch of water per day, there’s a good chance your pool is leaking.

Signs your pool might be leaking:

• Water loss exceeds typical evaporation

• Wet spots or soggy ground near the pool

• Air in the pool pump

• Algae growth due to untreated fresh water entering

• Cracks or gaps in the pool structure

  
  

Step-by-Step: How to Detect a Leak in Pool

Step 1: The Bucket Test (To Rule Out Evaporation)

• This is the easiest and most effective first step.

• Fill a bucket with pool water and place it on the pool step (partially submerged).

• Mark the water level inside and outside the bucket.

• Turn off the pool pump and wait 24 hours.

• Compare water loss inside vs. outside.

• If the pool water dropped more than inside the bucket, you likely have a leak.

  
  

Step 2: Inspect Pool Equipment

• Leaks often occur around.

• Pump and filter connections

• Valves (especially backwash valves)

• Heater or chlorinator fittings

  
  

Pro tip: If your backwash line drains water even when not in use, the multi-port valve or push-pull valve o-rings may be worn out.

Step 3: Look for Leaks in the Pool Liner

For vinyl or above ground pools:

• Turn off the pump.

• Add food coloring near suspected tears or seams.

• If the dye flows toward a spot, you’ve found the leak.

  
  

Pay close attention to:

• Ladder contact points

• Floor and wall seams

• Bubbling or wrinkled areas

  
  

Step 4: Examine Skimmers, Returns, and Lights

These fittings are common leak sources:

• Use dye around the skimmer throat and faceplate

• Check return lines, light niches, and steps

• Look for cracks in plaster or loose fittings

  
  

Step 5: Inspect Inground vs. Above Ground Pools

Inground Pools:

• Check tile lines, structural cracks, and expansion joints

• Monitor water levels after the pump is turned off

  
  

Above Ground Pools:

• Examine liner seams and skimmer seals

• Check where hoses connect to the filter or return jet

  
  

When to Call a Professional Pool Leak Detection Service

If your DIY checks don’t uncover the issue or if you suspect underground pipe leaks it’s time to call a technician.

A professional service can:

• Pressure test suction and return lines

• Perform a full dye test across pool components

• Use specialized sound and pressure detection tools

  
  

Trying to fix a leak without proper equipment can lead to further damage or missed issues. Professional technicians not only pinpoint the problem accurately but also recommend the most efficient fix.

Why Regular Pool Care Matters

Leak detection is just one part of maintaining a healthy pool. Routine pool maintenance ensures your equipment runs efficiently, prevents long-term structural issues, and helps catch small problems like slow leaks before they become expensive repairs.

Why Regular Pool Care Matters

Can I find a liner leak myself?

Yes. Turn off the pump and use food coloring near seams or bubbles in the liner to see if it’s pulled into a tear.

Is it safe to swim in a leaking pool?

How do professionals detect pool leaks?

How much water loss is normal in a pool?

Can pool leaks increase my utility bills?

Do leaks always show visible signs?