10 Steps to Winterize Above Ground Swimming Pools

pool-closed for winterThis post originally from 2012, is New and Improved and bumped to the top! 

Summer is over and with the end of summer comes the end of swimming; now is the time to prepare your swimming pool for winter.

Here’s my all-new 10 Steps to an above ground pool closing – prevent damage from snow and frozen water, and make pool opening next spring a breeze!

1. Balanced Water Chemistry

Taylor Troubleshooter test kitThe first step before closing the pool is to balance the water chemistry about a week before you are ready to close. Test your pool water and ensure that the chemical levels are within range:

pH: 7.2 – 7.6
Alkalinity: 80 – 120 ppm
Calcium Hardness: 180 – 220 ppm

2. Shock the Pool

pool shock, 1 lb.After balancing the water chemistry, and several days in advance of closing the pool, add a diluted granular chlorine, or non-chlorine pool shock to your pool water to remove any contaminants that could cause stains or algae during winter. The usual treatment is one bag (or pound) per 10,000 gals of pool water, for clear water. If your pool water is hazy or green, add double or triple the normal dosage. Use a brush afterwards, and brush the floor and walls until your arms wear out.

3. Clean the Pool

On the day of the pool closing be ready to clean your pool with your pool vacuum, brush and skimmer net. Clean it well before lowering the water, and skim again before covering the pool, to remove any wind blown debris.

It’s important to close the pool in a spotless condition. Any debris left in the pool will use up your winterizing pool chemicals, affect water balance, and create ugly stains.

4. Remove Accessory Items

hayward skimmer basket and return eyeballsRemove your skimmer basket, return fittings, solar blankets, pool alarms, ladders or steps, and pool cleaners. Dry and stow them safely for the winter months – indoors or protected from the elements.

Solar blankets can be left on the solar reel, and covered with our durable winter solar cover. They can also be dried, folded and stored in a location inaccessible to mice (probably not the shed).

5. Lower Water Level

Skimmer PlugNow, you can save the skimmer and save water at the same time with the aboveground pool Skimmer Plug. Just snap on the plastic skimmer cover and you can keep the water at normal levels. Drain the skimmer pipe, or disconnect the hose connecting to the pump.

If you don’t use a skimmer plug that fits into the opening to block water, you need to lower the water level below the mouth of your skimmer to prevent damage from frozen water. Lower the water level to about 3” below the skimmer opening. Removing too much water could stress your pool cover, liner or pool walls.

You can use your pool cover pump, or let the water run out of the return line hose by disconnecting it from the filter. If you have a low water suction line, in addition to the skimmer, close or plug the skimmer, and use the LWS line to lower the water below the skimmer, by setting the filter valve on waste or disconnecting the plumbing (next).

6. Drain & Plug the Pipes

For the return line, back to the pool: If you have filter hoses, use a #9 winter pool plug, or the threaded 1.5″ plug with o-ring on the return line – on the inside of the pool, and then disconnect the hose, draining it dry. If you have hard PVC pipes that cannot be removed, use a large wet/dry vac to blow (or suck) the water from the pipes, and add pool antifreeze for extra protection.

For the skimmer, remove and drain the hose connected to the pump. If you have hard PVC pipes, drain, suck or blow water out. Use a winter skimmer Plug to keep water out of the pipe during winter. PVC pool pipe cracks easily when the temperature falls below 32 degrees, so be sure that you get all of the water out, or add antifreeze if you’re not sure.

generic skimmer Gizmo, Skimmer GuardThe Skimmer Guard Gizmo is a combination skimmer plug and skimmer protector. It plugs the pipe to keep water out, but also absorbs ice expansion inside the skimmer. Skimmers can fill up during the winter, expand and easily crack a skimmer housing. The Skimmer Guard Gizmo absorbs the expansion, protecting the sidewalls of your skimmer. Includes a #9 rubber expansion plug to seal up the return line.

7. Drain the Equipment

350 gph pool cover pumpThe next step is to drain all the pumping, filtering, heating and chlorinating equipment and blow out all water from plumbing lines, otherwise the water will freeze and crack the equipment. After draining, pool pipes should be sealed at the pool with plugs, to keep water out of the pipes and equipment during winter.

Pumps have 1 or 2 drain plugs.
Filters have 1 cap or plug near the bottom.
Gas Heaters have drain plugs on each side.
Solar pool heaters have a union or a drain cap, or blow air thru the solar panels.
Heat Pumps loosen union nuts, slide back and tip the unit very slightly to drain.
Chlorinators or Purifiers have 1 drain plug.

pool heater and heat pump covers for winterBe sure to shut off the power and gas supply to gas-fired pool heaters. You can protect pool heaters and heat pumps with a Pool Heater Cover to prevent damage caused by snow, dirt, debris and animals. Moth Balls or mint sachets are also effective at keeping nesting mice out of pool heaters.

For DE pool filters and filter cartridges, a final cleaning and inspection is needed while closing the pool. Remove your filter grids or filter cartridge and hose very thoroughly.

Filter CleanerSoak in our Filter Cleaner to have grids or cartridges at their cleanest before replacing into the filter for dry winter storage. Sand filters also benefit from an end of year cleaning to remove oils and mineral scale, before it ‘sits and sets’ all winter long.

Finally at the equipment pad, be sure to shut off all power to the pump, lights, heater and other equipment. If you can easily remove the entire equipment pack for indoor storage, that would be best.

8. Lubricate O-rings

Magic LubeNow is also a good time to lubricate the soft rubber o-rings or threaded metal parts of your equipment. Use a Teflon based pool lube for rubber o-rings on your pump lid o-ring, filter tank o-rings, union o-rings, drain plug o-rings, or any other rubber o-ring on your pool equipment.

9. Add Winter Closing Chemicals

In addition to maintaining good water balance during the winter, adding winter algaecides and chemical floaters ensure that your pool water remains clean and clear during winter. Not having sufficient winter pool chemicals can lead to a long and costly spring clean-up.

A pool winterizing kit makes the process more convenient – just buy the winter kit that matches your pool size. In The Swim winter kits include algaecide, non-chlorine shock, stain & scale preventative, slow release floater and oil absorbing sponge. The Ultimate Winter Kit shown here, is what I use on my own pool, it has a few extra goodies.

10. Cover your Pool

intheswim winter pool coversLast but not the least; cover your pool with a tight fitting pool cover to ensure that debris and leaves cannot get into your pool. Winter Pool Covers for aboveground pools come in a variety of round and oval sizes, order by pool size for a perfect fit.

In addition to the winch & cable to secure your pool cover, there are many winter cover accessories like Wall Bags, Cover Seal and Cover Clips that help to hold down a cover in high winds.

Air Pillows are used in to break up the ice sheet that forms in the pool under the cover, during several days of below freezing weather. This prevents damage to the pool walls and skimmer from a solid sheet of ice expanding outward.

intheswim leaf catcherIf your pool is surrounded by large beautiful trees, put the Leaf Catcher on top of your winter cover. Lightweight and super tough mesh lets you remove all leaves and debris in one easy motion. Worth its weight in gold if you have large trees, like I do – saved me from hours of messy leaf dredging each year.

One more winter pool cover accessory is worth mentioning. You’ll need some way to remove the rain water and snow melt from the cover, either with an electrical or gravity fed pool cover pump.

That’s it ~ 10 little steps to closing your aboveground pool. Your pool may be slightly different. If you have questions about how to close it, or what products are needed, you can call our pool winterization experts anytime at 1-800-288-7946!


Ayesha Aslam
InTheSwim Staff Blogger




10 Steps to Winterize Above Ground Swimming Pools — 10 Comments

  1. Hello. I hope you can help. Is it okay to add PH Decreaser or Liquid Chlorine shock to pool to balance water AFTER using a winterizing kit in the pool, or what affect will it have on the winterizing chemicals? The water was not properly balanced prior to adding the winterizing kit…chlorine is slightly low and PH is on the higher side. Winterizing kit was just added an hour ago. We have an 18×33 above ground pool. Thank you.

    • Hi Missy, you can adjust the pH level, but high levels of chlorine can deactivate the winter algaecide. But, you can still add a little bit of chlorine, maybe 1/2 gal. per 10,000 gallons of pool water, to raise the chlorine level. Or you can also use non-chlorine shock, which won’t affect the algaecide, and give the pool water a good shocking.

  2. Thank you Davy! Also, can I run the pump for 4 hours only on weekdays and skip the weekends during winter (I have options to run it either on weekdays or weekends or everyday). Perhaps, that’ll extend the lifespan of the motor and save some energy?

    • Hi Lary, that would likely be OK. It may not extend the motor lifespan, but will save some energy. As long as the water continues to look good (not hazy, cloudy, green-ish), and there is very little stain causing debris, you could skip the weekends, and just filter m-f. each pool is different, or i should say that the efficiency and effectiveness of pumps and filters varies from pool to pool, so a larger system can get by with less filtering than one that is small, ineffective, or one that needs filter media replacement. (and water chemistry matters too!)

  3. Hello, I have an average-size saltwater pool in Sacramento and it’s not used during winter months (November-March). It gets cold during winter, but not freezing temperature cold. Question: Should I turn my pump off completely (will it damage the water?), or how long should I run the pump daily during winter months (while cold, but not freezing)? If I still need to run it, can I skip a few days weekly to preserve energy and extend motor life? Thank you!

    • Hi – I wouldn’t turn off the pump completely, which could lead to stains and algae growth. When the Water temperature is below 60 degrees, very little grows, but also your salt cell stops working at low water temperatures, so you may need to use chlorine tablets or dichlor shock (Di-Zap), to maintain a chlorine residual. Also important to manage pH and alkalinity and calcium during winter, just like in summer. Anyway, most people in your area run the pump about 4 hours per day during winter, or as needed, to keep the pool clean, and to create some circulation for water balance and sanitation. In general, you can run the pump about half as much during the winter months, as you do during summer months. Some experimentation may be necessary, to find how much your particular pool needs, to stay looking reasonably good. And of course, if the weather dips into freezing (below 32°), make sure the pump is running with all valves open, all night long, to prevent freeze damage.

    • Hi, there is no lubricant needed for the pump motor shaft seal, if that’s what you mean. O-rings on the pump and filter and other places around the pool can be lubed with Teflon based lube, like Magic Lube, Jacks 327, BOSS or other pool lubricants. Silicone is also available for pools, but is more suited for jandy valves or push-pull valves, surfaces in contact with lots of moving water.

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