You should partially drain your above ground pool for winter, lowering water level 4-6 inches below skimmer and return lines. Complete drainage can damage the liner and structure due to ground pressure and freezing.
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You should partially drain your above ground pool for winter, but never completely drain it. Lower the water level to 4-6 inches below the skimmer and return jets, then add winterizing chemicals and cover the pool. Complete drainage can cause serious structural damage to your pool liner and walls.
Above ground pools require partial drainage during winterization for several critical reasons. The water level must be lowered below all plumbing lines to prevent freeze damage to your equipment. When water freezes in pipes, skimmers, or return fittings, it expands and can crack these expensive components.
Additionally, maintaining some water in the pool is crucial for structural integrity. The water helps support your pool walls against ground pressure and prevents the liner from shrinking, cracking, or developing permanent wrinkles. A completely drained above ground pool can collapse under external pressures, especially in areas with unstable soil or high water tables.
The target water level depends on your pool's plumbing configuration. For pools with through-wall skimmers, lower the water to 4-6 inches below the skimmer opening. If your pool has above-ground plumbing connections, drain to just below the lowest return jet. This prevents water from sitting in lines where it could freeze and cause damage.
Before draining, balance your pool's chemistry for winter storage. Test and adjust pH to 7.2-7.6, total alkalinity to 80-120 ppm, and calcium hardness to 150-300 ppm. Add a winter algaecide according to package directions, typically 1 quart per 20,000 gallons. Shock the pool with liquid chlorine to achieve 10-12 ppm free chlorine, then add winterizing chemical kit following manufacturer instructions.
Use your pool's existing drainage system when possible. If your pool has a main drain, you can use the pump and filter system to lower water level, but monitor carefully to avoid running the pump dry. Alternatively, use a submersible pump to remove water more precisely. Sump pumps work well for this purpose and allow exact control over final water level.
As you lower the water level, begin winterizing your pool equipment. Remove all drain plugs from the pump, filter housing, heater, and any other equipment. Store these plugs in the pump basket so you won't lose them over winter. Blow out all plumbing lines using a shop vacuum or air compressor to remove remaining water.
Remove and clean your skimmer basket and pump basket. Install winter plugs in all wall returns and skimmer openings to prevent water from entering the lines. For pools with through-wall skimmers, install a skimmer guard or Gizzmo to protect against ice expansion damage.
In regions where temperatures regularly drop below 32°F, proper drainage becomes even more critical. Consider lowering water level slightly more in extremely cold areas, but never below the halfway point of your pool walls. Install air pillows under your winter cover to help prevent ice damage and reduce stress on pool walls.
In warmer winter regions where hard freezes are rare, you may only need to lower water level 2-4 inches below return lines. However, always err on the side of caution, as unexpected cold snaps can cause significant damage to inadequately winterized pools.
Never completely drain your above ground pool. This is the most serious mistake pool owners make during winterization. An empty pool can collapse, develop liner damage, or shift position, requiring expensive repairs or complete replacement.
Avoid draining too early in the season while temperatures remain warm. Algae growth accelerates in partially filled pools with warm weather, making spring opening more difficult. Wait until consistently cool weather arrives before beginning winterization.
Don't forget to remove water from equipment after draining the pool. Even small amounts of water left in pump housings or filter tanks can cause freeze damage requiring equipment replacement.
Proper winter drainage makes spring opening much easier. With correctly balanced water already in the pool, you'll only need to refill to operating level, reconnect equipment, and fine-tune chemistry. Pools that were improperly drained often require complete water replacement and extensive cleaning, costing hundreds of dollars in water and chemicals.
Plan to begin spring startup when nighttime temperatures consistently stay above 50°F. This timing prevents equipment damage from late freezes while ensuring your pool is ready for swimming season.
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