A Guide To Closing Your Pool For Winter: Winterising Checklist

Ensuring your pool and equipment are well-maintained and protected during the off-season means you’ll be able to open up again in spring with no problems and no unexpected costs. Properly closing your pool involves several important steps, so we don’t recommend just slapping on a winter pool cover and hoping for the best.

If closing your pool is on your to-do list this weekend, take a look at some of our winter closing tips and easy step-by-step guide.


Do I Need to Close My Pool for Winter?

To put it simply, yes, we would highly recommend closing your outdoor pool this winter. If you do not close your pool or prepare it for disuse, falling temperatures could cause freezing, leading to the formation of cracks or the expansion of existing ones. Plus, properly closing for winter will mean less time and effort to open again in spring. 

When Should I Close My Pool?

Before ticking off your winterising checklist, think about timing. You likely won’t want to close your pool too early as this can cause extra expense and work when spring rolls around again. Leaving your pool closed for too long can also damage your pool’s internal finish. 

The end of September is when most people in the UK start thinking about winter pool closure.

When temperatures start to creep towards and below freezing at night, it is a sure sign that you should begin the pool closing process.


How to Shut Down an Inground Swimming Pool for Winter

Understanding the ins and outs of pool closure is useful for any pool owner. While closing your pool down isn't an instant process, it shouldn't take too long once you have the right equipment and processes under your belt. 

How Do You Close a Pool Step by Step?

If you’re not sure where to start, consider the following steps:

  1. Remove debris
  2. Vacuum pool
  3. Lower water level
  4. Add winter chemicals
  5. Turn pump off
  6. Drain all pool equipment
  7. Remove and store ladders, rollers and solar covers
  8. Remove skimmer basket
  9. Cover pool with purpose-made winter cover
  10. Keep checking pool throughout winter


1. Remove Leaves & Debris

Start the winter closure process by getting rid of any rogue leaves or other debris lingering in your pool with a leaf net. Leaves left in the pool when it's closed will contaminate your water. They also contain tannin, which can stain the pool’s surface if left to decompose.

Do I Need to Clean My Pool Before Closing it? 

You may also take this chance to give your pool a good clean. Remember, you’re trying to protect your water from months of inactivity and don’t want any algae or bacteria growing. So, it’s a good idea to take a pool brush to the walls and floor to dislodge any remaining contaminants. The next few steps will help remove anything that’s dislodged and the bits of smaller debris that can’t be scooped up with a pool leaf net. 

Autumn leaves floating in a pool

2. Vacuum Your Pool to Waste

Once the debris has been removed and the dirt dislodged, you can vacuum your pool with a swimming pool vacuum. Vacuuming your pool to waste means you can bypass the filter and avoid reintroducing any algae back into your pool during the filtration process.

Put your filter multiport handle to the waste setting and close the sumps/low suction points – you can then vacuum your pool floor to waste, easily removing debris and contaminants.

Doing this can also help lower the pool water level, which leads into the next step.


3. Backwash Your Pool & Lower The Water Level

Close the skimmer/vac points and open the sumps/low suctions. Then, backwash your pool; again, to remove lingering contaminants and flush them through the waste line, ready for the winter period. When backwashing, you can also add a filter cleaner or remove and clean your filter if you’re using a cartridge to ensure you’re being thorough.

Once this is done, you can take the water level to just below the skimmers (unless you are in a high-ground water area). Your water level must sit below the skimmer to ensure that no water gets into the pump and filter systems during freezing temperatures. 

Do You Leave Water in a Pool Over Winter? 

Yes, while you need to lower the water level somewhat, you do not want to drain your pool completely as this can cause other issues with cold weather tearing your pool liner. Some covers may also rely on the waterbed below for support, so we don’t recommend emptying the pool or taking the water level down too far.

The easiest way to remove water from your swimming pool is by pumping it to waste as you would during the backwashing process.

Remember, you should never empty your pool in the winter and should remain mindful of your groundwater table.


4. Add the Right Winter Pool Chemicals

Re-circulate the water with the multiport valve on and begin adding the necessary chemicals that’ll keep your pool ticking over when it’s not in use. You’ll be familiar with the chemicals you need for a swimming pool during regular maintenance, but there are some specifics when considering winter closure.

We recommend adding:

Shop pool winterising chemicals at 1st Direct Pools

Allow the chemicals and water treatments to circulate through the system and thoroughly mix throughout the water. You can find out more about the whats and whys of winter pool chemicals in our guide to which chemicals you should put in your pool when closing

Do I Need to Shock My Pool Before Closing It? 

Yes, we certainly recommend shocking your pool before closing it down for winter. 

This will rapidly increase your water’s chlorine levels, killing off bacteria and contaminants to provide a clean slate of sorts as your pool heads in months of inactivity. Your regular chlorine doses won’t be able to increase your chlorine levels enough to eradicate chloramines (the waste product of chlorine), so a more powerful shock is necessary.    

Can I Close a Green Pool? 

Even though you won’t be swimming in the water, it’s not a good idea to close your pool with algae in it. Untreated algae left to its own devices over winter will cause bigger issues for you when it’s time to open the pool again. Not only will you have a harder time getting rid of it if it’s been left to grow, but algae can also cause unpleasant staining on pool walls and floors. Shocking your pool will help kill any algae present in your water, while a healthy dose of long-life algaecide is essential if you want to ensure algae stays away throughout the off-season. 


5. Turn the Pump Off

Once you’re sure the chemicals have thoroughly circulated throughout the system, turn your pump off and ensure the multiport handle is closed.


6. Drain the Pump & Filter

Once the pump is off, ensure all pool equipment is drained. Any remaining water may freeze, which can cause damage, incurring easily preventable additional costs for repairs.

Drain water from the pump, filter, heater, feeder, UV system and, essentially, any other parts that could freeze and put your kit at risk.

If there are any pipes or equipment that are not possible to drain or you want to provide additional protection, you can cover them. Something like a heat pump cover can be useful here.


7. Remove & Store Your On-Season Equipment

Keeping your pool functional and in good shape during the swimming season can require a lot of equipment, some of which you won’t need when your pool is closed for winter.

Remove any ladders, rollers and solar covers and store them away safely for next year. If storage space is limited, you could also use a winter PVC reel cover that’ll protect your solar cover throughout the winter and help extend its life.

We recommend storing all maintenance equipment inside to avoid damage.

A ladder going into a pool

8. Remove the Skimmer Basket

At this stage, you can remove the skimmer basket and store it somewhere sensible for next year. It is a good idea to put all the removed drain plugs in your pump or skimmer basket as they are easily lost, and you’ll want them on hand when opening again in spring.


9. Cover the Pool with a Quality Winter Cover

Before covering your pool, we suggest doing what you can to mitigate pool cracking – especially if it’s set to be a hard winter. You can do this by half-filling empty chemical containers with antifreeze, gravel or sand and float them in the corners of the pool, held together by ropes. This helps take up the expansion that can occur during freezing, effectively protecting concrete or tiled pools, which are liable to become cracked or loose.

In extreme cases, you may need to keep checking your pool throughout the month and break any ice that forms.

Once you’re confident everything else has been completed, it’s time to add the winter pool cover.

There are various winter pool covers, and which is best for you can vary depending on your circumstance and budget. What’s for sure is that these will do a much better job than a summer solar pool cover, so it’s worth investing in a seasonally appropriate option.

A winter cover over a pool

Essentially, your decision will come down to these two options:

  • Winter pool cover
  • Safety pool cover

As the name suggests, winter pool covers are designed specifically for the season. These are often fixed and protect the pool while allowing some water – such as snow – to pass through.

Safety pool covers are also designed to protect the pool over multiple months while having the added benefits of being robust enough to support excess weight. This is a good option if you want to prevent people or animals from falling into the water. If this isn’t an issue for you, a winter pool cover is more than suitable.

To make sure you install the right winter cover for your pool, you can use our winter pool cover calculator, allowing you to find a bespoke cover at a great price.


10. Check Your Pool Throughout Winter

Our final piece of advice in this instance is to keep checking your pool throughout the winter months. Keeping a regular eye on it will ensure you can address any issues as they arise and before larger problems develop.

Reduce the water level when needed and keep testing your water to see if more chemicals need to be added or adjusted.

Brown leaves on the wooden slats surrounding a swimming pool with a ladder in it

Pool Winterising Essentials

To summarise, you’ll need to ensure the following things are on your winter checklist:

  • Pool winterising chemicals
  • Winter pool cover and roller
  • Swimming pool cleaning equipment

What is the Best Way to Close a Pool For Winter? 

By following the above steps and treating it as a checklist to tick off, you should return to a pool that requires minimal attention in the spring. Putting in the work now makes it considerably easier to open come next season! 

Remember, we have everything you need for closing your pool, so check out our winterising products. For more advice, please call our technical line on 0333 900 4040.