As pool season wraps up and temperatures start to drop, one of the most common questions we hear is:
“Why don’t you drain the pool when closing it?”
It might seem logical to empty it before winter, but in reality, draining a pool can cause serious damage to both the surface and structure. Here’s why keeping some water in your pool through the winter is essential for its health and longevity.
🧱 Plaster Needs to Stay Wet
Your pool’s plaster isn’t just for looks—it’s a carefully applied, porous surface that must stay moist to remain stable. When plaster dries out, it begins to crack, chip, or “spall” (that’s when small flakes or chunks break away).
- Even a few days of dryness can cause visible damage.
- Once it cracks, repairs are costly and often require resurfacing.
Keeping water in the pool maintains moisture balance and protects the plaster from winter air, freezing temperatures, and surface stress.
💧 Water Supports the Structure
Water isn’t just for swimming—it also supports the weight and shape of the pool itself.
- Without water pressure inside, groundwater pressure outside the pool shell can cause it to lift, shift, or crack.
- Tile lines, steps, and fittings can move or pop loose when the pool sits empty.
Leaving the proper amount of water in place helps counterbalance this pressure and keeps everything where it belongs.
🛡️ Covers Need Water for Support
If your pool has a cover, the water underneath acts like a safety net—literally.
- Pool covers are designed to rest on the water’s surface for stability.
- Without that support, the cover can sag, tear, or pull on its anchors.
This water level helps the cover handle heavy snow or ice without stretching or damaging the hardware. This answers another common question
❄️ For Pools Without Covers
Even uncovered pools should never be completely drained. Instead:
- Lower the water just below the skimmer to prevent freeze damage.
- Balance your chemicals for winter.
- Add a winter algaecide and surface protectant.
- Leave handrails in the pool. In the event of an accidental entry, this will provide a means of escape.
These steps help prevent staining, cracking, and ice damage—keeping the pool ready for spring.
✅ The Bottom Line
Leaving water in your pool through the winter protects your plaster, structure, and cover. It keeps everything supported, balanced, and ready for a smooth spring opening.
In short:
💧 Don’t drain it—maintain it.
Your pool will thank you when it’s time to dive back in next season!
If you have more questions feel free to contact us.
