A British winter is hard on an outdoor pool. Frost, leaves and months of standing water can turn a clean pool into a green one, and a frozen pipe can mean a repair bill in spring. A proper winter closedown takes a few hours and saves most of that trouble.
Why it matters
Water expands as it freezes. Any water left in pipework, a pump, a filter or a heat pump can crack it. Even when the pipes survive, a pool left uncovered collects leaves that break down and feed algae, so the spring clean becomes a much bigger job.
How to winterise a swimming pool, step by step
- Test and balance the water first. Getting the pH and alkalinity right before you close stops scale and staining over the winter.
- Give the pool a thorough clean: brush the walls, vacuum the floor and empty the skimmer and pump baskets.
- Add a winter treatment suitable for your pool, following the product's dosing instructions.
- Lower the water level if your pool type needs it, so the skimmers and any wall fittings are protected from ice.
- Drain and protect the equipment that can't take a frost: pumps, filters, heat pumps and exposed pipework.
- Fit a well-secured winter cover, or close your automatic cover, to keep out leaves and light.
Should you keep the filtration running?
Many pools are better off with the filtration running for a short period each day through the winter, often on a frost thermostat that switches the pump on when the temperature drops. Moving water is much less likely to freeze and stays healthier for longer. Whether this suits your pool depends on its equipment and where it sits, so it's worth checking with your engineer.
Keep an eye on it
Look under the cover every few weeks. Clear standing water and leaves from the top of it, check the water level and add a top-up dose of winter treatment if needed. A short check now and then is far easier than a pool that has turned green by March.
Pool winterisation in Surrey, Berkshire and London
Our engineers close pools down for the winter across Surrey, Berkshire and London. We balance the water, protect the plant and equipment, fit the cover and leave you with a note of what we've done, so opening it up again in spring is straightforward.
Read more about our pool servicing, or call us on 01483 904704.
