Why Is My Pool Losing Water?

Why Is My Pool Losing Water?

1. Evaporation

Normal water loss from evaporation is about 1/8 to 1/4 inch per day, depending on:

  • Temperature: Hot, sunny days increase evaporation.

  • Humidity: Dry, windy conditions cause faster evaporation.

  • Pool usage: The more surface water is disturbed, the more evaporation happens.

Solution:
To confirm if evaporation is the cause, you can perform the Bucket Test:

  1. Fill a bucket with pool water to the same level as your pool.

  2. Place the bucket on the pool step (weighted if necessary).

  3. Leave it for 24–48 hours.

  4. If the pool water level drops more than the bucket water → you may leak.

2. Splash-Out or Backwashing

Water loss can also come from:

  • Kids playing, splashing, or diving.

  • Backwashing your filter.

  • Overflow from heavy rain and water displacement.

Solution:
Observe pool activity and recent maintenance routines. Splash-outs are common but generally minor, unless the pool is used heavily.

3. Leaks in Pool Structure or Plumbing

If you’re losing more than 1/4 to 1/2 inch per day, chances are there’s a leak somewhere in the system.

Common Leak Locations:

  1. Skimmer: Cracks around the skimmer throat or where it connects to the pool structure.

  2. Returns and Lights: Leaks can form where fittings penetrate the pool wall, especially around light niches or return jets.

  3. Tile Line/Expansion Joint: Separation between the pool shell and the surrounding deck can allow water to seep out.

  4. Plumbing Lines: Underground pipes leading to and from the pool may develop leaks, which can be harder to detect.

  5. Equipment Pad: Look for visible leaks around pumps, filters, valves, and chlorinators.

Solution:

  • Dye Test: Add a few drops of dye near suspected areas (skimmer, returns, lights) and watch for the dye being pulled into cracks.

  • Professional Leak Detection: If you can’t find it yourself, hire a pool professional with specialized pressure-testing or sonar equipment.

4. Pool Liner Problems (for Vinyl Pools)

For vinyl liner pools, tears or punctures can cause significant water loss.

Solution:

  • Scrutinize the liner for wrinkles or damage.

  • Use a vinyl patch kit for small holes.

5. Autofill Masking a Leak

If your pool has an automatic water fill system, it may be masking a slow leak by constantly adding water, making it harder to detect water loss.

Solution:

  • Turn off the autofill temporarily.

  • Monitor the water level for a few days to ensure it remains stable.

 

Cause Description Solution
Evaporation 1/8–1/4 inch/day normal Perform a bucket test
Splash-Out Heavy swimming, backwashing Limit splash, check backwashing
Structural Leaks Cracks in the pool shell or skimmer Dye test or professional help
Plumbing Leaks Broken underground lines Pressure test (pro help)
Liner Damage Tears in vinyl pools Patch or replace the liner
Autofill Hiding Leak Continuous filling covers water loss Disable autofill, observe levels

 

 

What to Do Next

  1. Do the Bucket Test first to rule out normal evaporation.

  2. Inspect visible areas around the pool and equipment.

  3. Check for damp spots or soggy ground around the pool perimeter and equipment pad.

  4. Call a leak detection specialist if the issue persists or if you suspect underground plumbing leaks.

If you want, I can help you write a step-by-step guide for homeowners on how to perform leak detection or recommend professional services depending on your location.

Let me know if you want a sample guide or another version of this for your blog or website.

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