How To Close My Above Ground Pool For The Winter
Properly winterizing your above ground pool requires balancing water chemistry, lowering the water level safely, and protecting structural components from freezing expansion damage. Completing this multi-step process before temperatures drop below freezing prevents costly liner tears, equipment cracks, and algae blooms by spring.
Pre-Operation & Equipment Checklist
Closing an above ground pool successfully demands careful preparation, timing, and the right combination of winterizing chemicals and hardware. Starting this process when water temperatures consistently drop below 65 degrees Fahrenheit prevents late-season algae growth while ensuring pool liners remain pliable enough for adjustment.
Essential Gear, Tools, and Materials:
- Winter pool cover (solid or mesh) and a heavy-duty cable with a winch
- Air pillow and air pillow inflator
- Submersible water pump and garden hose
- Pool closing kit (containing winterizing algaecide, stain preventative, and slow-dissolving winterizing pills or floating dispensers)
- Water testing kit or strips (pH, total alkalinity, calcium hardness, and free chlorine)
- Baking soda, soda ash, or muriatic acid (for chemistry adjustments)
- Skimmer plate cover or winter cap
- Non-toxic pool antifreeze (propylene glycol) if plumbing lines cannot be drained completely
- Plugs for return jets and skimmer ports
Prerequisite Standards and Knowledge:
- Water chemistry must be balanced precisely to prevent corrosion of metal walls or scaling on vinyl liners during the off-season.
- Never drain an above ground pool completely; hydrostatic pressure and freezing ground can cause structural collapse, wall buckling, and irreversible vinyl liner shrinkage.
- Estimated duration: 3 to 5 hours spread across two days depending on water balancing times.
- Estimated budget: 100 to 300 dollars for chemicals, plugs, an air pillow, and a heavy-duty winter cover.
Step-by-Step Winterization Workflow
Step 1: Deep Clean and Balance Water Chemistry
Begin by thoroughly skimming debris, brushing the pool walls and floor, and vacuuming the pool to remove all organic matter. Run the filtration system continuously for 24 hours after cleaning to ensure complete circulation. Test the water parameters and adjust them to the following ideal winter ranges: pH between 7.4 and 7.6, total alkalinity between 80 and 120 parts per million (ppm), and calcium hardness between 175 and 250 ppm.
Pro-Tip: Balance your water chemistry at least one week prior to adding winter algaecide to ensure sanitizers have dissipated to normal levels, allowing winter chemicals to work without interference.
Step 2: Shock the Pool and Add Winterizing Chemicals
Broadcast a non-chlorine shock or a high dose of liquid chlorine across the surface of the pool at dusk to eliminate remaining bacteria and organic contaminants. Allow the pump to run for at least 8 hours. Next, pour a long-lasting winter algaecide directly into the water around the perimeter of the pool. Follow the manufacturer's dosage instructions based on your exact pool volume in gallons. If using a winterizing floating dispenser, secure it to the center of the pool.
Warning: Never mix different pool chemicals together in a bucket, as hazardous chemical reactions, toxic gas releases, or explosions can occur. Always add chemicals directly to pool water.
Step 3: Lower the Water Level and Purge Plumbing
Use a submersible pump to lower the water level below the skimmer and return jet, typically 4 to 6 inches below the skimmer faceplate for solid covers, or up to 12 to 18 inches below if using a mesh cover or depending on manufacturer guidelines. Disconnect the hoses connecting the skimmer, return jet, filter, and pump. Drain all water completely from the filter tank, pump basket, and chlorinator to prevent freeze-cracking.
Step 4: Plug Lines and Protect Equipment
Insert expansion plugs into the pool return jet and the bottom of the skimmer throat to seal the interior from outside water infiltration. Blow out underground lines with a shop vacuum if applicable, and fill them with non-toxic pool antifreeze. Store your pump, filter system, and chlorinator indoors in a shed, basement, or garage where they are protected from freezing temperatures, rain, and snow loads.
Step 5: Install the Air Pillow and Winter Cover
Inflate your heavy-duty winter air pillow to about 60 to 70 percent capacity so it can absorb ice expansion pressure without bursting. Secure the pillow with nylon string to opposite sides of the top rail so it floats directly in the center of the pool. Center your winter cover over the pool, thread the heavy-duty cable through the eyelets, and tighten it securely using the winch mechanism. Place a water tube or cover weights around the exterior perimeter if you have an un-decked pool to prevent wind whipping.
How To Close An Intex Above-Ground Pool For The Winter — Peony Street
Technical Specifications for Winterizing Chemicals
| Chemical Parameter | Target Winter Range | Function & Purpose | Failure Risk if Ignored |
|---|---|---|---|
| pH Level | 7.4 – 7.6 | Prevents water from becoming acidic or basic | Acidic water corrodes metal walls; basic water causes scaling |
| Total Alkalinity | 80 – 120 ppm | Acts as a buffer to stabilize pH levels | Fluctuating pH damages vinyl liners and equipment |
| Free Chlorine | 1.0 – 3.0 ppm | Sanitizes organic load before closing | High chlorine destroys winter algaecide; low chlorine invites algae |
| Calcium Hardness | 175 – 250 ppm | Protects vinyl liner from degradation | Soft water leeches minerals directly from vinyl and pool walls |
Common Site Failures and Field Fixes
Collapsed Winter Cover Due to Snow Weight
- Root Cause: The cover cable was not tightened enough, or the air pillow deflated, allowing the cover to sink into the water under heavy snow accumulation.
- Actionable Fix: Pump standing water off the top of the cover, re-inflate or replace the air pillow, and tighten the cable winch securely around the top rails.
Green Algae Bloom Upon Spring Uncovering
- Root Cause: Water chemistry was unbalanced before closing, low-quality algaecide was used, or sunlight penetrated a damaged, thin winter cover.
- Actionable Fix: Shock the pool heavily with chlorine, run the filter continuously, add flocculant to drop debris to the floor, and vacuum to waste.
Cracked Return Fitting or Skimmer Housing
- Root Cause: Trapped water inside the plumbing lines or skimmer body froze and expanded during sub-zero temperatures.
- Actionable Fix: Replace the damaged skimmer faceplate or return fitting, and ensure all lines are completely drained and plugged with antifreeze next season.
Frequently Asked Questions
Should I drain my above ground pool completely for the winter?
No, you should never drain an above ground pool completely. The weight of the water provides crucial structural counter-pressure against outside soil and ice, preventing the pool walls from buckling, collapsing, or causing the vinyl liner to shrink and crack permanently.
How do I keep my winter cover from blowing away in high winds?
Ensure the winch-tightened cable is pulled as taut as possible around the perimeter channels. For added security in windy regions, wrap a heavy-duty cover wrap or strap around the entire circumference of the pool walls, or use water-filled cover weights spaced evenly around the top rail.
When is the exact right time to close my above ground pool?
The ideal time to close your pool is in autumn when the water temperature consistently stays below 65 degrees Fahrenheit. At this cooler temperature, bacteria and algae reproduction rates slow down dramatically, making your winterizing chemicals last much longer until spring.
Can I leave my pool pump and filter outside during freezing weather?
Leaving your pump, filter, and chlorinator outside with water inside them will cause the plastic housings and internal components to crack when temperatures drop below freezing. Always disconnect these units, drain them thoroughly of all remaining moisture, and store them in a dry indoor area.
Protect your backyard investment and ensure crystal-clear water next season by following this complete winterization guide carefully. Start gathering your closing supplies today to beat the first freeze.
