Do I Have a Pool Leak?
If your pool is losing water, the question is always the same:
Is this normal evaporation — or do I actually have a leak?
Most pool owners don’t see obvious signs like spraying water or flooded yards. Instead, they notice subtle symptoms:
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Water level keeps dropping
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Salt or chemicals won’t stabilize
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Autofill runs constantly
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Pump pulls air or loses prime
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Water bill suddenly increases
This page walks you through simple, reliable steps to confirm abnormal water loss, identify leak patterns, and avoid guessing.
Four States Leak Detection serves Missouri, Kansas, Oklahoma, and Arkansas — and these are the same checks we recommend before scheduling professional leak detection.
How Much Water Loss Is Normal?
All pools lose some water to evaporation.
Typical evaporation:
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Around ¼ inch per day in hot, windy, or dry weather
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Slightly more with heavy use or water features
Likely a leak if:
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Loss exceeds ¼ inch per day consistently
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Loss continues during cooler or calm weather
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Water drops faster overnight
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Water loss changes when the pump runs
Step-by-Step: How to Confirm You Have a Pool Leak
Follow these steps in order. One test alone doesn’t always confirm a leak — patterns do.
Step 1: Turn Off the Autofill (This Hides Leaks)
Autofill or auto-leveler systems can silently replace lost water while the pool leaks underneath.
What to do:
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Turn off the autofill valve or shut off its water supply
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If it can’t be fully shut off, mark the waterline and monitor more frequently
Why it matters:
Autofill systems can hide leaks for months while water bills rise and salt or chemical levels become unstable.
Step 2: Mark the Water Level Correctly
Use painter’s tape or a pencil mark on the skimmer faceplate or tile line.
Best practice:
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Mark the level at the same time each day
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Choose calm conditions (no swimming, minimal wind)
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Track for 24–48 hours minimum
Step 3: Perform the Bucket Test (24 Hours)
The bucket test compares evaporation to pool water loss.
Bucket Test Instructions
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Fill a bucket about ¾ full with pool water
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Place it on a pool step or hang it so it won’t float
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Ensure the bucket water is exposed to the same air conditions
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Mark the water level inside the bucket
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Mark the pool water level
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Wait 24 hours
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Measure both drops
How to Read Results
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Pool drops about the same as the bucket → likely evaporation
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Pool drops more than the bucket → likely a leak
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Pool drops significantly more → strong leak indicator
Rule of thumb:
Consistent loss over ¼ inch per day, especially after the bucket test confirms it, usually means a leak.
Step 4: Pump ON vs Pump OFF Test (Very Important)
Many leaks behave differently when the system is running.
24-Hour Split Test
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Day 1: Run the pump normally for 24 hours and record water loss
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Day 2: Leave the pump OFF for 24 hours and record water loss
What the Results Mean
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More loss when pump is ON → often a pressure-side plumbing or equipment leak
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More loss when pump is OFF → often a shell, skimmer, or suction-side issue
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Same loss either way → could be a structural or consistent underground leak
Step 5: Check the Equipment Pad for Obvious Leaks
Before assuming the leak is underground, inspect the equipment area.
Look for:
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Wet soil or puddling around pump, filter, heater
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Drips at unions, valves, or waste lines
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Water from the backwash discharge when not backwashing
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Pump shaft seal leaks (often water under the pump)
Pro tip:
Run the system and watch the pad for 10–15 minutes — some leaks only show under pressure.
Step 6: Monitor Salt Loss (Saltwater Pools)
Salt does not evaporate.
If salt levels keep dropping, water is leaving the pool or being diluted by autofill.
What’s Normal
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Backwashing removes some salt because water is discharged
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Typical loss: 2–8 lbs per backwash
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Many pools only need ½ to 1 bag per season
What’s Not Normal
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Adding salt weekly
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Adding multiple bags per month
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Salt levels that never stabilize
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Low-salt warnings returning quickly after adding
These are strong indicators of ongoing water loss.
Step 7: Watch Chemical Demand
If you’re constantly adding:
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chlorine
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stabilizer
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acid
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salt
…more than normal, it may mean treated water is leaving the pool and being replaced with fresh water.
This alone doesn’t confirm a leak — but combined with water loss, it supports it.
Step 8: Look for Physical Leak Clues Around the Pool
Inspect:
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Skimmer throat and faceplate
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Return fittings and jets
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Pool light niche
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Steps and corners
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Deck joints and coping
Signs include:
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Soft or sinking soil
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Persistent wet spots
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Settling or cracking deck sections
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New cracks near the pool
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Air bubbles in returns
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Pump losing prime
Step 9: The “Stops Dropping Here” Clue
If you allow the pool to drop (with autofill off) and it stops at a specific level, that elevation often points to the leak:
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Stops at skimmer mouth → skimmer-related leak possible
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Stops at return fitting level → return penetration suspect
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Stops below lights or steps → those penetrations become suspects
This is a strong clue, but still requires proper testing to confirm.
What to Do If These Tests Suggest a Leak
If the bucket test confirms abnormal loss — or if water loss increases when the system runs — professional leak detection prevents wasted money and unnecessary damage.
At Four States Leak Detection, we locate leaks using:
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Pressure and isolation testing
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Acoustic listening equipment
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Dye confirmation
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In-pool inspections (often without draining)
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Non-destructive diagnostics whenever possible
When to Call Four States Leak Detection
Call or text us if:
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You confirmed loss beyond evaporation
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Your autofill hides water loss
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Water loss increases when the pump runs
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Salt or chemicals won’t stabilize
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You notice soft ground, settling, or wet areas
📱 (417) 660-9130
Flat-rate detection • No find, no charge
Pool Leak Detection Across the Four States
Four States Leak Detection serves Missouri, Kansas, Oklahoma, and Arkansas.
We don’t remodel.
We don’t upsell.
We find and fix leaks.