Swimming Pool Closing

Swimming pool closing is something that all pool owners have to do at the end of the season when the weather cools off or you decide to shut the pool down for an extended period of time. A proper winterization routine is essential to keeping your pool healthy while it sits stagnant and your pool system isn't running because this is when it's most susceptible to unhealthy algae growth or expensive damage. 

swimming pool closing

Winterizing is an important step whether you own a salt water pool or a regular chlorine pool and will help make spring start up a whole lot easier as well as reduce the time and chemicals needed to get your pool ready. There is nothing better than removing the cover and finding pool water that looks as good as when you last saw it the previous year.  

Pool owners that live in the northern United States or Canada that experience freezing temperatures in the winter will have to ensure that all water is removed from the plumbing system to avoid damage to pool hardware. Water that is left to freeze in plumbing will expand and could cause serious damage to expensive parts that will most likely need to be replaced. 

If you live in a climate that doesn't experience freezing temperatures in the southern United States or Australia you can get away with not removing water completely from the plumbing but it's still a good idea. Pool owners in this type of climate the goal will be to create a water solution that prevents long term algae growth and water health without circulation.

There are some specific swimming pool closing instructions for salt water pool owners that we will go over below. If you have an above ground pool check out our winterizing above ground pool page with unique steps to ensure you are closing your pool properly. 

salt water pool maintenance guide

Swimming Pool Closing Step by Step

If this is your first time carrying out swimming pool closing for your salt water pool make sure you read all the instructions. A properly balanced pool is very important to prevent future headaches and costly damage. A lot can happen during the winter months especially if you live in a climate with fluctuating temperatures that including algae growth and stains that can be difficult to remove.

1.  Final Balancing

The water chemistry in your pool should be balanced at all times but it's really important that its balanced heading into winterizing. If levels are a bit off you should adjust accordingly to ensure that your closing chemicals work as effectively as possible. 

  • pH: 7.2-7.8 (7.5 optimal)
  • Alkalinity: 80-120 ppm
  • Free Chlorine: 2-4 ppm
  • Salinity: 2500-4500 ppm (as per the system manufacturer)
  • Cyanuric Acid: 50-80 ppm
  • Calcium Hardness: 200-400 ppm

For more information on optimal chemistry visit our salt water pool maintenance page that has tips and advice for salt water pool owners. 

2.  Final Cleaning

With the pool water level still full it's a perfect time to give your pool walls and floor a good scrub. We recommend a biodegradable pool cleaner if you find it necessary but good old elbow grease is usually sufficient. Any dirt and residue left to sit over the winter months can end up staining your liner so it's a good idea to get the liner as clean as possible. 

3.  Pool Closing Chemicals

A pool closing kit is a convenient way to ensure that you have everything you need to keep your pool healthy during the off season. A good kit will help prevent pool algae that can sometimes form during fluctuating winter temperatures. It will also prevent cloudy water in the spring and possibly the need to perform a pool shock.

If you want to ensure you get your pool water conditioned properly make sure it includes a scale inhibitor, oxidizer and algaecide. You can purchase them separately or in a kit for added convenience and a reduced cost. Closing kits are designed for use with pool for a certain size or gallonage just ensure that the kit you purchase is rated for the size of your pool. 

Scale Inhibitor

A scale inhibitor will guard against scale, metal staining and the ring that can form along the pool surface liner. A bottle of scale inhibitor is usually enough and should be poured evenly around your pool during application. 


A bottle of oxidizer added to the pool water 4-6 hours after the scale inhibitor will dissolve organic matter that your filter doesn't screen out. 


An algaecide will prevent your pool from developing algae growth that can form with fluctuating temperatures in the off-season. One bottle is enough mixed in a bucket to dilute and should be poured evenly around the pool. 

4.  Lower Water Level

After you have given your pool liner a good cleaning it's time to lower the water level according to they type of cover you are using. This will ensure that your system does not take any water in and will help reduce staining. If you are using a mesh cover we recommend lowering the water 12-18 inches and if you are using a floating cover 3-6 inches should be sufficient. 

If your pool has a drain you can set it to the appropriate setting or you may have to use a water pump or shop vacuum. A gizmo can be used to plug the intake line in the skimmer for added protection.

5.  Hardware Preparation

Electricity should be turned off at the main control panel and plumbing disconnected from the pump, filter, heater, salt system and skimmer. Any water should be drained from adjacent valves and left open to allow for evaporation.

If you are using a cartridge filter or D.E. filter the filter cartridges should be cleaned and removed for storage. If you are using a sand pool filter you may have to clean the sand by hand or wait until spring to run a backwash. 

At this point it's important to ensure that all plumbing and equipment is completely free of water. You may have to use a shop vacuum or an industrial blower to remove any remaining water. Once you are sure that all water is eliminated it's time to refasten plumbing and an expandable rubber plug can be used to plug open airways.

If you are unable to remove the water completely you can use anti-freeze by filling the skimmer as per manufacturers instructions. 

6.  Salt Water System Winter Setting

If your salt chlorine generator has a winter or neutral setting ensure that it is set.  It's important to remove the cell for the winter especially if you live in a climate with freezing temperatures. A good cleaning with a mild acidic solution is recommended at this time also and if you want more information on cleaning visit our salt water pool cell page. 

7.  Remove Pool Accessories

It's time to remove accessories from you pool including anything that isn't water. It's a good idea to give them a good rinse and store them away from the winter elements. Pool accessories include; ladders, diving board, toys, etc. and if you are unable to remove your diving board or slide it's a good idea to cover it with a weather resistant cover to protect it for the winter.

8.  Winter Cover

This is the last step of swimming pool closing and one of the most important.  Install an inground pool cover that fits your pool with room to spare. The cover will help preserve all the hard work you put into getting your pool ready for winter. A good cover that securely fastens to your pool deck is ideal to keep the elements, debris and anyything else out of your pool. 

This step by step guide should help ensure that your swimming pool closing is done properly and you are ready to forget about your pool over the winter months. Your pool will be clean and in tip top in the spring.

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