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Pool Winterization

Pool Winterization

A guide line for those closing their own pool.

*(or preparing for the closing of a pool by a pool service.)

General Goals :

*1) Ensure overall condition of pool:

2)Protect Circulation Equipment From Frost:

3)Cover Pool

4)Storage of accessories

Ensure the overall condition of pool:

Leaks: If the pool is losing water into the winter months you may not be able to diagnose or repair the problem after the pool is closed.

If the pool is losing any noticeable water(¼”/day or more) be certain

it wont allow the winterized pool to drain unnecessarily.

The water in a pool protects the base & foundation from frost damage.

Note the level after closing and be certain its not dropping.

Proper Water chemistry must be achieved in the weeks leading up to a pool closing. Chemicals cannot be added to a closed pool

Leave Pool Running and clean until the day you close the pool: A circulating Pool will remain cleaner and prevent frost damage just by having the water circulate through the equipment.

Protecting Circulation Equipment from Frost:

The expansion of water when it freezes & thaws will damage any piece of equipment in which it is trapped. Each part of the pool should be considered both separately and together when considering the best way of preventing frost damage:

~either Drain it

~and/or Get plumbers antifreeze throughout it

~or Store it in a frost free area

A general approach

Winter level : pump or siphon water out of the pool below the level of the return jets {about 14“ below summer level}.

While doing this give the filter a final backwash and the pool a final vacuum on waste.

Fixtures & fittings below the winter level need to be dealt with individually.

Main drain equalizer line :{when the main drain line is hooked to the base of the skimmer; insert a foam expansion rope down the main drain line and seal off the line with a plug & Teflon tape.

Lights: remove the light from the niche where it rests(leave sealed and attached to wire) and force it to sink using a plastic bag and smooth round stones. Be certain the power is permanently off for the winter.

Blow out lines :

~remove eyeballs, suction grates and baskets from the pool side of all fixtures.

~Place Filter valve on recirculate and undo the drain plug on the tank

~Empty Chemicals from any vessels attached to the pool plumbing

i.e. chlorinator.

~Force as much water as possible out of the underground lines using an air blower, compressed air or a good wet/dry shop vac.

Blow from the equipment to the pool if possible.

Tackle each line separately by: Sequentially turning valves; breaking open the system at valve unions, Clamped fittings or open the pump. Fittings connected to the same lines may have to be plugged off and unplugged sequentially in order to clear the lines.

Force Plumbers Anti-freeze through each of the lines in the same manner by which you blew them out. Likewise, force antifreeze through the pump, multiport valve, heater and all of the circulation equipment.

Plug Off all lines with an appropriate expansion plug or threaded plug as needed.

Drain Circulation Equipment : follow manufacturers recommendations to further ensure the protection of your equipment.

Cover the pool

The goal of a cover is to maintain to some degree the water quality in the pool between closing & opening.

A cover is not essential

Tarp style winter cover or Lock-in style

Tarp style covers are inexpensive to replace, and often the only effective way for a pool with waterfalls & water side features to be effectively covered. They are more prone to being caught by the wind. Water bags are placed end to end around the edge, in order to create a seal on the uneven deck, against wind and worms, they will then freeze solid where they sit. Usually several bags a year will need to be replaced. When a water bag falls in a pool it has smooth edges and generally floats due to the air trapped in it. When alternate heavy items such as concrete blocks or slabs are used they do not seal as well and are prone to being blown in. When they do fall in with the cover they inevitably damage the pool. Custom made tarps are also available.

Lock-in covers consist of a fabrene or vinyl tarp custom made to fit the pool. Along the edge is a bead of vinyl which clips into an extra track in the coping. The step needs to be covered separately with a piece of tarp, board or rigid cover. Usually, extra pieces of locking strip is needed to keep the cover in the track, however, this depends on the coping & bead.

Security Cover A Heavy mesh cover usually custom made to fit each pool. Straps at 3 to 5’grid intervals each have a compression string at either end which retains the tension on the cover. Holes are drilled in the deck; concrete is ideal however they have been installed in both wood and interlock decks. A pop-up anchor is inserted at each hole, these thread flush for summer use.

A heavy snow load will cause the cover to sink & rest upon the water below. A steel bar is used to slide the tension springs onto the anchors.

Automatic Cover Built in covers activated by a switch require a perfectly rectangular track system which is either mounted on the deck or built into the pool and landscaping. A motor & cables cover & retract the pool as required.

Although expensive, this is the optimum in convenience and security.

Storage of Accessories:

Solar blanket : cleaned and put away can also be washed with mildew resistant cleansers; most are left on the roller and covered with an opaque piece of plastic.

Ladders: cleaned and put away

All the small bits and pieces should be stored so that they’re easy to find come opening time.

Pressure gauges last longer if stored inside.

Iron threads are best smeared with a light grease to prevent rusting.

I.e. diving board jig & iron heater header drain threads.

However you don’t want grease in the pool.

Heater turn off the gas valve in the heater as well as on the gas line.

Moth balls or some other bug-rodent deterrent may assist in keeping the internal parts of a gas heater from


Electric power to any equipment should be permanently disconnected to prevent accidental operation.

Automatic Cleaner : hose sections are better stored if separated, laid flat & straight.

After the fact : look out the window and make sure the water level hasn’t dropped, and the cover has stayed more or less on. Once its frozen there’s little to be done about either.