Caring for your pool through winter

Just a couple of weeks ago, we were talking about ways to squeeze every last bit of enjoyment out of your outdoor pool - heating solutions, cosy lighting, clever covers, and other ways to stretch the season. Many of our clients did exactly that well into October.

But now that temperatures have dropped across the UK and the nights are drawing in, it’s time to shift gears. While we love the idea of extending pool use, there comes a moment when the smart move is to hibernate your outdoor pool - to protect your investment, save energy and avoid problems in spring.

Why Winterisation Is Best Handled by Professionals

Winterisation isn’t as simple as closing a lid and walking away. Cold weather puts pressure on equipment, pipework, structural finishes and water chemistry. A trained pool engineer knows how to safeguard each of these elements - and how to spot subtle issues that could become major problems if left unattended.

What Our Engineers Do During a Winterisation Service

1. Deep cleaning and debris removal

Before shutting a pool down, engineers give the entire system a thorough clean. They skim the surface, vacuum the floor, brush walls and tiles, and ensure the filtration system is cleared and backwashed. This helps prevent staining, algae growth and debris build-up during the dormant months.

2. Water balancing and specialist chemical treatment

A pool engineer carefully tests and adjusts pH, alkalinity and sanitiser levels for long-term stability. They administer shock treatment at the correct concentration, followed by professional-grade winter algaecide formulated to last throughout the season. This prevents algae, scale and surface deposits - and makes spring opening far easier.

3. Protecting the plant room, pipes and equipment

This stage is especially difficult to do safely without expertise. Engineers:

• lower the water level to the correct point (varies by design)
• drain or blow out vulnerable pipework
• protect pumps, heaters and filters from freezing
• inspect valves, seals and fittings for early signs of wear

Freezing damage is one of the most common causes of costly repairs - and also one of the most preventable when winterisation is carried out professionally.

4. Installing and securing a winter cover

A winter cover is far more than a cosmetic finish. The pool engineers ensure it is correctly tensioned, securely fixed, and able to shield the pool from leaves, debris and UV exposure. They also check for wear or weakness, reducing the risk of mid-winter problems.

Remember Winter Check-Ups (Even When the Pool Is ‘Asleep’)

Once the pool has been professionally winterised, many people assume it can simply be left alone until spring. In reality, a well-closed pool still benefits hugely from one or two mid-winter service visits - and these visits can prevent the most common (and expensive) springtime surprises.

Here’s why they matter:

1. Water chemistry shifts over time

Even with winter chemicals in place, pH and sanitiser levels drift naturally as rainwater, frost and temperature changes influence the balance. A mid-winter visit allows an engineer to:

• test and rebalance key levels
• re-dose winter treatment if needed
• prevent algae from developing under the cover

This saves hours of corrective work during reopening.

2. Covers can loosen, sag or take on excess weight

Winter covers endure strong winds, heavy rain, fallen leaves and occasional snow. If they sag or loosen, debris can slip into the pool or strain the fixings.
The pool engineer will:

• check tension and fixings
• remove excess debris
• ensure rainwater isn’t pooling on top

A secure cover protects the pool - and the surrounding paving - throughout the harshest months.

3. Plant room checks catch early issues

Even when not running at full capacity, the plant room still faces moisture, cold air and frost. These can affect pumps, valves, seals, pipework and electrical components. Mid-winter inspections help identify early signs of wear or freezing risk before they become springtime repairs.

4. Cold weather can expose structural issues

Tile joints, grouting, coping stones and sealant are more vulnerable in winter conditions. Engineers can spot early problems while they are still minor and inexpensive to fix.

5. Peace of mind for the owner

Check-ups mean you do not have to wonder what is happening under the cover during stormy nights or frosty mornings. Your pool remains protected - and you avoid the “April shock” of discovering issues that went unnoticed for months.

A Natural Step After Extending Your Season

If you embraced autumn swimming this year, wonderful. Those late-season swims are exactly why modern heating, covers and design exist. But now that the cold has truly arrived, winterisation is the sensible next step.

It isn’t an ending - it’s a protective pause. When handled by professionals, winterising your outdoor pool ensures that when warmer days return, you can open the cover, restart the system and enjoy a seamless return to swimming.

Ready to Book Your Winterisation?

Our engineers at London Swimming Pool Company are experts at preparing pools for winter. If you would like to schedule a winterisation service or a winter check-up, get in touch and we’ll take care of everything.