If you’ve noticed your pool losing water, you’re probably asking the same question we hear all the time: “Is this normal for evaporation, or do I have a leak?” The reality is, most pools will lose some water, but in many cases, what homeowners assume is normal evaporation turns out to be an active leak. Check out our pool leak detection services to learn more about our process.
Below are the most common signs we see in the field, and how to tell when it’s time to take the next step.
Quick Signs Your Pool May Have a Leak
There are a few common patterns that often point to a leak. If you find yourself adding water every few days, noticing water loss that exceeds normal levels, or dealing with a pump that struggles to stay primed with air in the system, it may indicate a problem. Other signs can include air bubbles coming through the return lines, wet or soft areas forming around the pool, or the water level consistently dropping to a certain point and then stopping. If you’re seeing one or more of these conditions, there’s a strong chance your pool may be leaking.
How Much Water Loss Is Normal in a Pool?
A swimming pool naturally loses water through evaporation.
In New Jersey and New York, approximately 1/8 to 1/4 inch of water loss per day may be normal under typical summer conditions. That works out to roughly 1 to 2 inches per week.
Evaporation can increase with:
- Hot temperatures
- Low humidity
- Wind
- Direct sunlight
- Heated pool water
- Large differences between daytime and nighttime temperatures
- Water features that increase exposure to moving air
Once you’re consistently losing 1/2 inch or more per day, it’s worth paying closer attention. A pool losing 1 inch per day is losing approximately 7 inches per week, which is far beyond what we would normally expect from evaporation alone.
We’ve worked on pools losing 1 to 2 inches every day, but smaller leaks can also be significant.
If you’re trying to determine whether your water loss is normal, read our Pool Leak or Evaporation Guide.
Common Signs Your Pool May Have a Leak
1. Your Pool Is Losing Water Every Day
Consistent water loss is the most obvious sign of a swimming pool leak.
Homeowners often describe the problem to us in inches:
- “I’m losing about 1/4 inch per day.”
- “The pool drops 1/2 inch overnight.”
- “I’m losing an inch every day.”
- “I have to put the hose in every couple of days.”
The rate matters.
A small amount of daily water loss may be evaporation, particularly during hot or windy weather. If you’re losing 1/2 inch, 1 inch, or more per day consistently, a leak becomes much more likely.
Don’t rely solely on a general evaporation estimate. Weather conditions vary considerably from one property to another.
The easiest next step is our Pool Leak Bucket Test. It compares water loss from your pool against evaporation occurring at your property during the same 24-hour period.
2. You’re Constantly Adding Water to the Pool
If putting the hose in the pool has become part of your weekly routine, pay attention.
A pool shouldn’t require constant refilling just to maintain its normal operating level.
Adding fresh water can temporarily hide the problem because you never see how far the water would naturally drop. Meanwhile, the leak continues.
Frequent refilling also affects your pool chemistry because treated pool water is being lost and replaced with untreated fresh water.
If you’re unsure how much water you’re actually losing, mark the water level and monitor it over 24 hours or perform a bucket test for your swimming pool.
3. Wet Spots Around the Pool or Deck
Wet soil, soggy grass, soft areas around the pool, or moisture that repeatedly appears near the deck can indicate an underground leak.
This is particularly important when the area remains wet despite dry weather.
Water escaping from underground pool plumbing may travel through the soil before reaching the surface, so the wet spot isn’t necessarily directly above the broken pipe.
You may also notice:
- Soil becoming unusually soft
- Pavers beginning to settle
- Washout around the pool
- Damp areas near the equipment
- Water appearing through cracks or joints
Keep in mind that not every underground plumbing leak creates a visible wet spot. Soil conditions can allow significant amounts of water to disappear underground without anything obvious appearing at the surface.
4. Air Is Getting Into the Pool Pump
Air entering the circulation system can be another warning sign.
You may notice:
- Air inside the pump basket
- The pump struggling to maintain prime
- Air bubbles coming from return jets
- Equipment behaving differently than normal
Air in the system can sometimes point toward a suction-side plumbing problem, although other equipment-related issues can produce similar symptoms.
The symptom alone doesn’t confirm an underground leak. It tells us that the plumbing and circulation system deserve closer attention.
Professional testing can isolate individual plumbing lines and determine whether they are actually leaking.
5. You Notice Cracks Around the Pool
Not every crack in a swimming pool leaks, but some absolutely can.
Cracks may develop around:
- Gunite or concrete pool shells
- Steps
- Skimmers
- Fittings
- Tile lines
- Structural penetrations
A crack becomes more suspicious when it appears alongside unexplained water loss.
The important thing is not to assume that every visible crack is responsible for the problem. We’ve seen plenty of pools where an obvious defect attracts attention while the actual leak is somewhere completely different.
Leak detection is about confirming the source before making the repair.
6. Your Water Bill Is Increasing
A leaking pool can consume a surprising amount of water.
If you’re constantly refilling the pool, that additional usage eventually appears on your water bill.
An unexplained increase during pool season can therefore be another clue, particularly when combined with noticeable changes in the pool’s water level.
The amount of water involved increases quickly. Even seemingly modest daily water loss adds up when it continues for weeks.
Instead of continually replacing the missing water, determine why it’s disappearing.
7. You’re Having Trouble Maintaining Pool Chemistry
A leak doesn’t just remove water.
It removes treated water containing chlorine, salt, stabilizer, and other chemicals you’ve already paid for.
When you continually replace that lost water with fresh water, chemical levels become diluted.
You may find yourself:
- Adding chlorine more frequently
- Adding salt more often
- Struggling to maintain stabilizer levels
- Rebalancing water chemistry repeatedly
- Using more chemicals than previous seasons
If your chemical demand has suddenly changed at the same time you’ve started adding more water, a leak may be contributing to the problem.
8. Algae Keeps Coming Back
Recurring algae isn’t automatically a sign of a pool leak, but unexplained water loss can make algae control more difficult.
Constantly adding fresh water changes the pool’s chemistry. If sanitizer and stabilizer levels are repeatedly diluted, maintaining consistent water conditions becomes harder.
If you’re fighting algae while also adding substantial amounts of water every few days, don’t look at those problems separately.
First determine why the water level keeps dropping.
9. Your Pool Loses Water to the Same Level and Stops
This is one of the more useful clues homeowners can give us.
If your pool repeatedly drops to approximately the same height and then appears to stop losing water, look at what is located around that waterline.
Possible leak sources may include:
- Skimmers
- Return fittings
- Pool lights
- Liner damage
- Cracks
- Other penetrations through the pool structure
As the water reaches the height of the leak, water loss may slow considerably or appear to stop.
Do not intentionally drain the pool trying to find the problem. Simply make a note of the level where the water appears to stabilize and tell your leak detection technician.
Seeing Any of These Signs?
In many cases, these symptoms point to a leak, but the only way to confirm it is through proper testing such as pressure testing.
Learn how we locate leaks using advanced, non-invasive methods on our non-invasive leak detection process page.
Pool Losing Water – Pump On vs Off
A simple way to gather useful information is to compare water loss with the system running and when it is off. You can learn more about this method with our pump on vs pump off test.
Losing more water when the pump is on often points to a pressure-side plumbing leak
Losing more water when the pump is off often points to a suction-side plumbing leak
Losing water at the same rate either way often points to a structural leak source such as:
- Vinyl liner leaks (holes or tears)
- Pool light or light conduit leaks
- Cracks in skimmers or fittings
- Leaks in the pool shell (concrete pools)
While the on/off test isn’t a definitive test, it can help narrow down where the issue may be coming from.
Where These Signs Can Lead
Underground Plumbing Leaks
These are among the most common leaks we find, and one of the most frequently misdiagnosed. Because they are underground, they cannot be visually confirmed and are often missed by companies that rely on visual observation alone.
Identifying these leaks properly requires pressure testing, specialized diagnostic equipment, and years of hands-on experience testing and isolating plumbing lines to accurately pinpoint the source of the leak without unnecessary digging. Learn more about underground pool plumbing leaks.
Vinyl Liner Leaks
Small punctures, holes, tears, or seam separations in vinyl liners can cause steady water loss and are often difficult to detect without the use of electronic testing devices.
Pool Light Leaks
While the light fixture itself can leak, in many cases the issue is not the light, but the conduit behind it, which allows water to escape from the pool and travel beneath the surrounding patio.
We routinely find leaks in this area that have gone unnoticed, allowing water to erode the soil beneath the deck, which can cause sections of the patio to settle or shift.
Skimmers and Fittings
Skimmers, returns, and other wall fittings are common leak points due to movement, age, or seal failure.
When to Call a Professional
These signs are important, but they don’t confirm the exact problem. We routinely see situations where the symptoms point in one direction, but the actual leak is located somewhere else entirely. While leak detection is a science, it’s not always straightforward, so without proper testing and diagnostics, it’s easy to misdiagnose the issue.
Why Proper Leak Detection Matters
Accurate leak detection allows the problem to be fixed correctly the first time. Without it, homeowners often end up repairing the wrong area, wasting money on unnecessary work, or digging without knowing where the issue actually is. Professional leak detection uses pressure testing, electronic listening equipment, and non-invasive methods to pinpoint the exact source of the leak, ensuring the right solution is applied from the start.
Frequently Asked Questions
Can a pool leak come and go?
Some leaks may only occur under certain conditions, such as when the system is running or when the water level reaches a specific point. We routinely see leaks that appear inconsistent but are still active and will get worse over time.
Are underground leaks common?
Yes. Underground plumbing leaks are one of the most common issues we find and cannot be identified through visual inspection alone. Proper pressure testing and diagnostic equipment is required to confirm the leak.
Do I need to drain my pool?
No. Almost every leak detection is performed with the pool filled using non-invasive testing methods.
Can leaks get worse over time?
Yes. Leaks may remain consistent for a short period, but they almost always get worse if they are left unaddressed. Leaks do not fix themselves.
How do I know if my pool is leaking or if it’s evaporation?
The only way to confirm a leak is through proper testing. Signs can point you in the right direction, but testing provides a definitive answer.
Unsure If Your Pool Is Leaking?
See our Pool Leak Detection Services in New Jersey & Staten Island
If you’re unsure whether your pool is leaking, contact us for help or call 732-333-3304.
