Is My Pool Leaking or Just Evaporating? How to Tell the Difference

In New England, it’s normal to top off a pool now and then—especially during warm, breezy weeks. But if you’re adding water constantly, you start wondering: is this evaporation, or do we have a leak? We get this question all the time from homeowners in Hudson, NH and across the region.

Below, we’ll walk through practical ways to tell the difference, including the classic bucket test described by American Leak Detection. If you confirm a leak (or you just want a pro to pinpoint it fast), call us at 888-611-7665 or request an estimate.

Quick answer: leaking vs evaporating

If your pool water drops more than a bucket of pool water placed in the pool drops over the same 24-hour period, you’re likely losing water from a leak—not just evaporation.

• Evaporation: Pool and bucket drop about the same.
• Leak: Pool drops noticeably more than the bucket.

What’s “normal” evaporation in New England?

Even in our cooler climate, evaporation can be surprising. Wind, low humidity, and sun exposure can accelerate water loss. American Leak Detection notes that pools lose about around a quarter inch of water per day on average, with weather conditions changing that baseline (typical pool evaporation guidance).

Why New England pools can evaporate faster on certain days

• Windy afternoons: Coastal breezes and open backyards can move a lot of air over the surface.
• Big temperature swings: Cool nights and warm days can increase evaporation.
• Heaters and waterfalls: Anything that warms water or increases surface agitation can boost evaporation.
• No cover: An uncovered pool loses far more water than a covered one.

• Evaporation is usually steadier and tied to weather.
• Wind + sun can make “normal” evaporation look like a problem.
• If you’re losing water regardless of weather, test for a leak.

The bucket test (step-by-step)

The bucket test is a simple way to compare evaporation to your pool’s actual water loss. The steps below follow the method outlined by American Leak Detection (bucket test procedure).

What you’ll need

• A 5-gallon bucket
• Painter’s tape or a marker
• A ruler (optional, but helpful)

How to run the bucket test in 24 hours

1. Bring the pool to its normal operating level.
2. Fill a 5-gallon bucket with pool water to about 1 inch from the top.
3. Turn off any auto-fill device (if you have one).
4. Place the bucket on a pool step so it’s immersed roughly 5 inches.
5. Mark the water level inside the bucket and the pool water level outside the bucket.
6. Wait exactly 24 hours, then compare the two drops.

How to interpret the results

• If the pool level drops more than the bucket level, it points to a leak.
• If they drop the same amount, it’s likely evaporation.

• The bucket test is the fastest DIY way to separate evaporation from a leak.
• Turn off auto-fill and avoid rainy days for accuracy.
• Check at the 24-hour mark for the clearest result.

Other signs you may have a leak (not evaporation)

1) You’re refilling more often than the weather explains

If you’re topping off every day even during calm, mild conditions, that’s a red flag. This is especially true in Hudson, NH where spring weather can be cool but still windy.

2) Wet spots, sinking pavers, or eroding soil near the pool

Unusual soggy areas around the deck, under downspouts, or along the equipment pad can indicate water escaping underground. If you’re also considering deck work, take a look at pool decking and deck resurfacing to understand repair options.

3) Air in the pump, difficulty priming, or water under equipment

Small suction-side leaks can pull air into the system and cause bubbles at returns. Pressure-side leaks can leave obvious puddles at valves, unions, and filters. If equipment issues are part of the problem, our pool repair services team can help diagnose the whole system—not just the shell.

• Persistent water loss in mild weather is suspicious.
• Wet soil or shifting pavers near the pool can indicate underground loss.
• Equipment-pad puddles and air bubbles can point to plumbing leaks.

Common leak locations we find in New England pools

When we’re called out for leak detection and repairs, these are common culprits:

• Skimmers: Cracks where the skimmer meets the pool wall, especially after freeze-thaw cycles.
• Return fittings and lights: Failed gaskets or loose niches can let water seep out.
• Vinyl liner tears: Pinholes and seam failures can be hard to see until you dye-test.
• Plumbing lines: Settling soil or old joints can open up small leaks that worsen over time.
• Tile line and coping: Movement and water intrusion can create pathways for loss.

If your pool surface is aging or cracked, it may be time to look at pool resurfacing plaster options as part of a long-term fix.

• Freeze-thaw damage can create leaks at skimmers, fittings, and coping.
• Liner issues and plumbing leaks often need professional testing to locate.
• Surface cracks can be both a cosmetic and water-loss problem.

When to call a professional leak detection / repair team

DIY testing is a great start, but we recommend calling for help if:

• The bucket test indicates a leak (pool drops more than bucket).
• You see wet spots, settlement, or suspect plumbing underground.
• You can’t keep the pool at a stable level for more than a day or two.
• You’re losing water fast enough to affect skimmer function or pump priming.

We serve homeowners across New England, with many service calls in and around Hudson, NH. Call 888-611-7665 or request an estimate, and we’ll help you confirm the cause and prioritize the most cost-effective repair.

FAQ

How much water should a pool lose in a day from evaporation?

Evaporation varies with weather, but American Leak Detection notes an average of about a quarter inch per day, with wind, humidity, and sun changing the rate (daily evaporation factors).

Does running the pump increase evaporation?

It can. More surface movement, spillovers, and waterfalls can increase evaporation, especially on windy days.

Can a small leak really waste that much water?

Yes. Even a slow leak adds up over a week, and it can also undermine soil under decks and equipment pads.

If the bucket test shows a leak, what’s the next step?

We recommend turning off auto-fill (if present), documenting the drop, and scheduling a diagnostic visit. If the leak is tied to surface cracking, we may discuss resurfacing; if it’s plumbing, we’ll isolate lines and test them.

Need help now? Call Affordable Pool Repair at 888-611-7665 or request an estimate. We’ll help you get answers quickly and keep your pool ready for the New England swim season.

Related reading: Why Gunite Pools in Rye NH Develop Surface Damage · How Freeze-Thaw Cycles Affect Pool Tiles in Andover MA · What to Do When Pool Tiles Crack in Nashua NH