The Right Way to Close Inground Pool for the Season: A Complete Guide

When should you close your in-ground pool for the season? How should you do it? What are the safety precautions you should follow? Read this complete guide to learn how to close inground pool for the season without any problems.

Winter is a delicate time for your inground pool.

When the pool season is off, and your pool is starting to get really cold for swimming, there’s a lot to do before you can close it for the season. 

This guide will have all the information you need to know about closing an inground pool. It’ll help make this job less daunting by making it easier than ever before. Plus, if something goes wrong, now you know how to fix it.

The best part? You’ll have less work next spring when you’re ready. 

Ready? Let’s dive in. 

Why You Should Close Inground Pool for Winter?

Pool owners should close their inground pools when winter comes because it helps to protect pool equipment. Another benefit is that you’ll be able to maintain a clean and beautiful pool for the next spring. 

Closing your pool isn’t only for next year; it’s also to help you now. If you close the pool, you will avoid the effort and expense of cleaning debris and adding chemicals, as well as running your pool pump and circulation system, which can cost a lot.

If you’re not swimming, that’s a lot of time and work that’s simply unnecessary—even if you have a very cost-effective variable speed pump.

Prepare the Gears You Need

Pool Maintenance Materials

You’ll want to start preparing for the winter months, so start planning now. Fortunately, you most likely already have most of this equipment on hand. And although it’s quite a long list, don’t worry. Anything you buy this year will be useful next year. Here’s everything you’ll need to get started:

  • Winter pool cover
  • Swimming pool brush
  • Pool vacuum, automatic vacuum, or robotic cleaner
  • Winter pool plugs for return jets
  • Skimmer plug
  • Shop-vacuum or compressor
  • WinterPill
  • Tools to remove pool accessories, e.g., ladders, fountains, and lightings
  • Pool cover pump

Prepare the Chemicals You Need

Pool Chemistry Test Kit
  • Chemical test strips
  • Chlorine or sanitizer
  • pH increaser
  • pH decreaser
  • Alkalinity increaser
  • Calcium hardness increaser
  • Algaecide
  • Pool shock
  • Metal sequestrant
  • Cyanuric acid
  • Antifreeze
  • Pool enzymes

Step 1: Put a Lot of Effort to Clean Your Pool

Man Cleaning In Ground Pool with Brush

Before doing anything else, you should clean your pool. Use a pool brush linked to a telescopic pole to scrub the walls and floor of your pool, making sure to get into all of the nooks and crannies as possible.

This will assist in picking up any silt that may be there and disturb the growth of any algal spores that may be present. Manually vacuum up all the debris that was kicked up throughout the brushing process.

You will need to put a lot of effort into cleaning your swimming pool. Not only does this mean that you’ll want to wash the steps, ladders, filter slots, and the skimmer basket with your pool brush. But you’ll also want to take the time to remove the filter cartridge and scrub it thoroughly in a bucket to properly close your inground pool.

Step 2: Test Your Pool Water

The proper test strips will allow you to know your pool’s pH and alkalinity to determine whether the water is balanced. When the pH is too high, it can cause scale buildup on the pool surfaces and disrupt the balance of your pool. On the other hand, when the pH level is too low, chlorine levels could increase, which could reduce the lifespan of certain pools’ equipment.

To effectively preserve your pool from corrosion and scale buildup that might occur when you close your inground pool, you must maintain the correct pH, alkalinity, and other values.

Important note: "Check to see that the chlorine level is less than 5 parts per million (ppm). Chlorine levels that are too high could destroy the additives that you've put in your pool's water before they have the chance to function." - Matt Giovanisci, founder of Swim University®

Step 3: Apply Winterizing Chemicals

Once your water is balanced, you can add winterizing chemicals. These will include chlorine and bromine to protect against algae growth and antifreeze for protection against freezing. The most common form of antifreeze is ethylene glycol, although propylene glycol works equally well. 

These pool closing chemicals come in different strengths that you need to check the instructions before adding them to the pool. Also, it would be excellent if you were careful to only add the proper amount of antifreeze to your pool water.

Depending on where you reside and what sort of water you have, you may not require all of these winterizing chemicals to close your inground pool.


Add one dosage to prevent algae development throughout the winter. If your cover is a mesh panel or a cover with the point of entry for dirt, leaves, or other debris, add a double dosage of algaecide before you close the pool.

Metal Sequestrant

Metal sequestrant is an additive that can be used to keep metallic substances like iron or copper from staining the pool’s water.

Pool enzymes

Pool enzymes will increase the effectiveness of these chemical applications by breaking down organic compounds that could otherwise build up on your pool surfaces and potentially lead to corrosion or scale buildup during long periods without use.


When you use chlorine tablets or floaters to winterize a pool, they may not dissolve or disperse properly, especially because the pump will be shut off for the majority of the time, if not the entire off-season.

To avoid potential harm when you close your inground pool, utilize products intended for use in a closed pool, such as a WinterPill. It includes a sanitizer and clarifier but dissolves over many months under the winter cover. 


Some pool owners will add a mixture of water and antifreeze when they plan to close the pool for an extended period of time. This mixture protects the pool from freezing in temperatures below 50 degrees Fahrenheit or 10 degrees Celsius.

Choose one that is rated -10°F (-12°C). If your winter temperatures are considerably colder than that and you still choose to use antifreeze, verify the temperature rating of the product you pick to ensure that it can effectively protect your pool in those drastic temperature changes.

If you plan to use antifreeze, make sure you get the type intended for use in swimming pools rather than automobile antifreeze. The pool-safe version is non-toxic compared to the automotive version.

Step 4: Shock Your Pool

Pool Shocking

Shock your pool one last time before you close the pool. Use shock treatments to balance the pool’s chemistry levels. When shocking, you need to ensure that you are using a fresh chlorine pack or tablet for this process; otherwise, it will not be effective.

Aftershock means the chlorinated pool water reacts with all organic compounds usually trapped in the pool’s water during the off-season. This will then break down remaining algae spores that may have been present before to prevent them from growing. Lastly, this will ensure that your chemicals are still working before it gets too cold during the winter.

Keep the pump running overnight to distribute the pool shock throughout the pool and circulation system. Test your water the following day to ensure it’s balanced.

Step 5: Lower the Water Level of Your Pool

The purpose of lowering the water of your pool at the end of the season is to avoid frost damage and, to a lesser extent, overflow. Your water level should be an inch lower than the tile border. It’s an excellent idea to check the water level while the pool is closed if you have a thaw or a wet winter.

Step 6: Backwash and Thoroughly Clean the Pool Pump and Filter

Swimming Pool Pump Cleaning Water

The last thing you want to do is leave a slew of unpleasant dirt and germs accumulating in your filter throughout winter. Get rid of all of the muck before you close the pool so that you may start the next pool season with a sparkling-clean filter.

Cartridge filter:

  1. Remove the cartridge from the water.
  2. Clean it with a pool filter cleaner or muriatic acid.
  3. Rinse it well.
  4. Allow it to dry completely before hiding it in a safe place.

Sand filter:

  1. Remove debris or any other visible dirt near the skimmer basket.
  2. Invest in a vacuum hose attachment if you don’t already have one.
  3. If necessary for your sand filter model, remove any visible debris by rotating the skimmer cover plate on top of the sand bed by hand; make sure you get all of that muck out! You will need to do this for each vaned-plate assembly on top of your filters.
  4. Ensure that pressure isn’t too high when vacuuming so you don’t damage the filter.

Step 7: Blow the Water Line

Time to clear those lines. Everything has been straightforward up to this point. However, for this step, things become a little more technical before you can properly close the pool.

Therefore, if you lack the necessary equipment or knowledge, we highly advise you to hire a professional pool service to assist you in clearing your lines. They’ll do the work quickly and safely.

Otherwise, you may do the task yourself by following the procedures outlined below:

  • Start by opening up the main valve and the skimmer lines.
  • Connect an air compressor (or a shop vac) to the pool pump drain plug (You may need a special attachment for you to connect the pump drain plug).
  • Switch on the compressor.
  • Keep an eye on bubbles coming out of the return line.
  • Once bubbles are visible, continue plugging each line one at a time, starting with the skimmer. (You can use a skimmer guard to connect to the skimmer opening).
  • As soon as you notice bubbles coming out of the main drain on the floor of your pool, switch off the compressor. (Make sure to close the suction valve as necessary).
IMPORTANT: Now may be the perfect time to remove pool accessories surrounding your pool, like pool ladders or slides.

Step 8: Install a Pool Winter Cover

In Ground Pool Covered for Winter Season

Installation of a winter cover can be a tricky and time-consuming process. Follow the directions given by the manufacturer and avoid any changes to the pool structure itself.

How you do this depends on the pool cover type you install. All covers require that you cover your pool entirely with plastic or other material.

Whichever type of winter cover you choose, you must begin preparing your pool for the cold temperatures by lowering the water to prevent freezing. Your pool must be kept as clean as possible and make sure that the pool cover is clean as well when you close your inground pool.

Bottom Line

Cleaning, maintaining and closing your pool this winter not only prevent fatal accidents but there are several other benefits that you may be missing out on. The pool cover, mainly the winter cover, is your only opportunity to keep it safe from harsh conditions. It safeguards your investment from tough conditions and also helps preserve the overall conditions of your pool.

For great pool articles, check out our website. Swimming pools are not as difficult to maintain as you might think. Here are a few tips to help you. Keep your pool clean and safe.

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