Inground Pool Winterizing Procedures


I remember one customer when calling for his pool winterization, would always say “Time to Button Up the Pool!” You may call it a pool closing, or have another expression.

Inground pool closings are more involved than aboveground winterization, of course. More water, more pipes, more equipment.

Nonetheless, the process is the nearly the same. Here’s my step-by-step for an inground pool winterization process.

Clean the Pool

It’s got to be clean. If there are leaves, dust or algae in the pool, your winter pool chemicals will be absorbed too quickly, and not last until spring.

Clean the surrounding deck as well, with a blower, or with buckets full of pool water on a windy day. This will help keep the pool clean as you finish winterizing the pool.

Right before you put on the winter pool cover, you may need to run the skimmer net around the pool one more time.

Lower the Pool Water

6-12″ below the skimmer for mesh safety covers, or 4″ below for solid covers. You can lower the water by backwashing the filter, and closing the skimmer valve or plugging the skimmer when water gets low, to allow you to continue pumping below the skimmer.

If you have a multiport valve on the filter, you’ll get better flow rates by setting the valve on the Waste setting, which will bypass the filter.vacuum-hose

For pools with non-functioning or abandoned main drains, you can connect the non-swivel end of a vacuum hose, sealed tightly into the skimmer with a threaded hose adapter, (or enough duct tape). Then set a garden hose running into the skimmer to keep it from sucking air. In this manner you can pump the pool below the skimmer, without using the main drain.

A third method is to use a submersible pump. A powerful pool cover pump will lower the water quickly, a small cover pump takes overnight. Utility pumps used as sump pumps are very fast, only needing a few hours at most.

Blow out the Lines

For those in the sunbelt, If you only have the occasional dip below the freezing mark, you may not need to actually blow the lines, but could just lower the water and pour some pool antifreeze into the skimmers.

For those snowbelt pools, that will have continuous below freezing temperatures, for several days or weeks on end – you’ll want to blow air through the plumbing lines to prevent underground freeze damage.

air-compressorAir Compressor: A small air compressor can be used to pump air into the pump basket. Remove the pump drain plug and thread in the air hose adapter, or screw in the air hose. With the use of plugs and valves, you can direct the air to go through the pump, filter, heater, and bubble at the pool returns. Switching plugs or valves, direct the air the other direction, through the skimmer and main drain lines. Be careful not to exceed 20 lbs of pressure when using an air compressor.

Blower Box: A Vac Blower, as they are sometimes called, are used by pool guys (like me), to blow out lines. It has the advantage of producing high flow of air, in CFM, with relatively low pressure, which is the opposite inclination of an air compressor. cyclone-pool-line-blower

A Cyclone can be connected into one of the skimmers and air is blown from the skimmer to the other skimmers and drain, and then through the pump, filter, heater and to return bubbling at the pool, which are then plugged with expansion plugs.

shop-vacShop Vac: Maybe. If it’s at least a 5 hp, and won’t bleed off excess air pressure when it builds up against the resistance of the water being pushed through the pipes. There are some canister wet/dry vacs that will hold a little back pressure, and can be used by reducing the shop vac hose down to a pool vac hose size, and connecting it to a threaded hose adapter that is screwed into the bottom of the skimmer. It may not blow a main drain, but should blow the other lines out if they are not too deep underground.

Caution: Be careful when sending air through pool equipment. Open filter air bleeders and be certain that pump lids and filter lids are tightly secure.

Winterize the Pool Equipment

  1. Drain the pump, filter, heater, chlorinator, pipes, valves etc.
  2. DE filters and Cartridge should be left in tank after cleaning.
  3. Lubricate pump lid o-ring.skimmer-guard
  4. Shut off breaker to pump and pool light.
  5. Remove salt cells for indoor storage.
  6. Use a Skimmer Guard, or a clean algaecide bottle 1/3 full of pool antifreeze.

Add Winter Pool Chemicals

If you are using a winterizing kit, just add the chemicals, following the instructions included. If you don’t use a winter kit, here’s a winter pool chemical recipe.

  1. Several days to a week before closing, balance the chemistry and shock the pool. Run the filter a little longer each day.
  2. On closing day, after lowering the water level, add 1 Qt of winter pool algaecide, for pools up to 20,000 gallons. Use our Winter Algaecide or Algaecide 60 Plus as a winter algaecide.
  3. Fill a chlorine floater carefully with 5-6 chlorine tablets, and close the holes nearly all the way.
  4. Use a Stain & Scale product to keep minerals from depositing on the surfaces and stains from forming at the water line.

For pools with mesh covers, larger pools, or pools that open late or open green, you’ll need more winter pool chemicals. Add another quart of algaecide in the spring, about 4-6 weeks before you open. Or, you can pull back the cover along the sides and shock and brush the pool instead. Either way, find the floater and refill it with chlorine tablets.

Put on the Pool Cover

Pool is clean – check! Water lowered, pipes blown and plugged and chemicals added … check! Time to cover up the pool for winter!

Safety Covers: Using the Hex Key and the Installation Tool, install the cover springs onto the brass anchors surrounding safety pool covers.

Solid Covers: Lay the water bags or Aqua Blocks end to end around the cover, and move the hose around the pool, if you have enough hose. Fill bags only 2/3 full, and position them so they won’t roll off the deck. Set the cover pump on the pool cover, ready for rain.button-up-the-pool

Congratulations, you’ve “buttoned-up the pool” or “put the pool to bed” – however you want to say it!

If you have any questions on how to winterize your specific pool, leave a comment below or call one of our helpful tech support folks.

Davy Merino
InTheSwim Blog Editor


Inground Pool Winterizing Procedures — 2 Comments

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