It's common for an older pool to show hairline cracks in the plaster, and not every crack leaks — many are surface-only and cosmetic. The challenge is telling which ones are actually letting water through. We use dye testing to confirm which cracks are active leaks, then seal them so the water loss stops and the crack is less likely to spread.
What a plaster or crack leak is
A pool's plaster is the waterproof coating over the concrete shell. When a crack goes all the way through the plaster and into the shell, water can seep out into the surrounding ground. These leaks are often slow — a steady drip rather than a gush — which is why they can run for months before the water loss becomes obvious. Cracks can appear in the floor, walls, steps, or around fittings.
Signs of a plaster or crack leak
- A visible crack in the plaster that's wider than a hairline, or one that's grown over time
- A wet or soft spot on the deck near where a crack runs on the pool wall
- Water loss that doesn't match evaporation, with no obvious plumbing cause
- Discoloration or staining along a crack, where water has been moving
Why South Florida pools develop cracks
Cooper City pools sit in sandy soil with a high water table. The ground shifts between wet and dry seasons, and that movement stresses the concrete shell over time. Intense sun heats the pool deck and shell unevenly, adding thermal stress. Older plaster also becomes more brittle with age, so cracks that once stayed on the surface can eventually work through to the shell. Pools that were resurfaced years ago may be due for attention.
How we find a leaking crack
Not every crack leaks, so we confirm before repairing:
- Dye testing — with the pump off, we release dye along the crack. If the dye is drawn into the crack, water is moving through it and it's an active leak.
- Visual inspection for wider cracks, staining, or cracks that align with settling in the deck.
- Checking around fittings — cracks often start where the shell is weakest, near skimmers, returns, and lights.
What repair usually involves
For an active crack, we clean and widen the crack slightly to give the sealant a good surface to bond to, then apply a flexible pool-grade patch or sealant designed to move with the shell. For larger structural cracks, we may recommend a more involved repair that addresses the underlying movement. Surface-only hairline cracks that aren't leaking generally don't need repair, but we'll point them out so you can watch them.
When to call us
If you see a crack that's wider than a hairline, one that's grown, or staining along a crack, it's worth checking. Even a slow seep can erode the soil behind the shell over time. The earlier an active crack is sealed, the less chance it has to widen and cause a bigger problem.