My Ottawa pool lost 2 inches of water overnight — is that normal evaporation or a leak?

Two inches overnight is almost certainly a leak, not evaporation. Normal evaporation in Ottawa's climate runs about a quarter to half an inch per day in hot, dry, windy summer conditions — losing two inches in a single night points strongly to water escaping somewhere it shouldn't be.

The quickest way to confirm this is the bucket test. Fill a five-gallon bucket with pool water, set it on a pool step so it's partially submerged, and mark the water level inside the bucket and on the pool wall. Wait 24 hours without running the pump. If the pool loses significantly more water than the bucket, you have a leak. If they drop by roughly the same amount, that difference is evaporation — though two inches overnight is high enough that you'd want to repeat the test before ruling out a problem.

Once you've confirmed a leak, the next step is narrowing down the source. The most common culprits in Ottawa pools are the skimmer faceplate (the gasket behind it degrades over time, especially after Ottawa's freeze-thaw cycles), return fittings, the main drain, and the liner itself if you have a vinyl pool. Run the pump for a full day, then turn it off and watch whether the leak rate changes — if the pool loses water faster with the pump running, the leak is likely in the plumbing or equipment side; if it slows or stops, the shell or liner is more suspect.

For vinyl liner pools, you can often find small tears yourself using a few drops of dark food colouring or leak detection dye held near suspected areas underwater. The dye will drift toward the leak. Small tears in the liner body — away from fittings — can be patched with an underwater vinyl patch kit for $15 to $30 at any pool supply store, and this is a reasonable DIY repair. Tears at fittings or seams, or any leak you can't locate visually, warrant a professional leak detection service.

The Ottawa-specific concern here is timing. If you're heading into fall and losing water, you absolutely cannot let this go unresolved before closing. An Ottawa winter with a low water level or an active leak can allow ground water pressure to push against the liner or shell, and if the water drops below the return fittings before you close, frost damage to exposed plumbing becomes a serious risk. A two-inch-per-night loss over a week is 14 inches — that's enough to cause real problems by closing time.

Professional leak detection in Ottawa typically runs $200 to $500 for a full inspection using pressure testing and dye methods, and most pool service companies can pinpoint the source within a few hours. If you need help finding a qualified pool professional to investigate, you can browse pool and spa contractors through the Ottawa Construction Network directory at justynrookcontracting.com/directory.