Winterize an Above Ground Pool by Yourself

Closing your above ground pool for winter isn’t about doing “everything”—it’s about doing the right things in the right order. A clean pool with balanced water, protected equipment, and a tight cover will wake up in spring clear, safe, and cheap to reopen. This guide walks you through an easy, step-by-step DIY process tailored for U.S. climates, from mild winters to hard freezes.

When to Close

The sweet spot for closing is when water temperatures stay below 60°F (≈16°C) for about a week. Below that threshold, algae can’t multiply easily, so your sanitizer works longer under the cover. Close too early—when the water is still warm—and you trap organics and sunlight, practically inviting a green surprise by March. In the Sun Belt or coastal regions where water rarely dips that low, you can either run a shortened daily pump schedule all winter (“soft close”) or follow this full close with occasional checks.  

What You’ll Need

You’ll want a reliable water test kit or high-quality strips; a chlorine shock product (or a non-chlorine oxidizer if that’s your preference); a Polyquat 60 algaecide (gentle, long-lasting, non-foaming); an air pillow; a tight-fitting winter cover with cable and winch plus optional cover clips; and a cover pump to remove rain and snowmelt. If you use a skimmer winter plate or a threaded skimmer plug, you usually won’t have to lower the water level. Keep a couple of towels, Teflon tape, and labeled zipper bags for storing small parts.

Step 1: Do a Real Pre-Close Clean

Start with the water as clean as you can get it. Brush the walls, floor, and waterline to dislodge biofilm, then vacuum thoroughly. If you prefer to skip manual vacuuming, a cordless robotic unit can handle the heavy lifting; for example, a Beatbot pool cleaner can sweep the floor, walls, and even hug the waterline while you take care of chemistry. The cleaner the pool is at closing, the less sanitizer it consumes over winter and the faster your spring opening will be.

Backwash a sand or D.E. filter after vacuuming, or deep-rinse a cartridge filter and let it dry if you plan to remove it for storage. Empty skimmer and pump baskets.

Drop in Beatbot pool robot cleaner to remove fine dust, leaves, and stuck-on film before you shock and cover. Its cordless design avoids hoses around an above-ground pool, and the large, easy-rinse basket keeps suction strong as it works from floor to waterline. Run one full cycle, empty the basket, and you’re ready to balance, shock, and close with clearer water and fewer chemicals at spring opening.

Step 2: Balance the Water

Aim for pH 7.2–7.6 and total alkalinity 80–120 ppm. In vinyl-lined above-ground pools, calcium hardness is more forgiving than in plaster pools; keeping CH around 175–250 ppm is sufficient in most regions. Adjust alkalinity first (baking soda to raise; dry acid or muriatic acid to lower), then fine-tune pH (soda ash to raise; acid to lower). Wear gloves and eye protection when handling acids and always add chemicals to water, never water to chemicals.

Stabilizer (cyanuric acid, CYA) above 60–70 ppm can make shock less efficient. If yours is high from a trichlor summer, consider a modest partial drain/refill now, which also helps dilute dissolved solids—combine this with your water-level step to avoid extra work.

SEE ALSO Why pH in Pool Water Is So Important

Step 3: Shock the Water

The idea is to oxidize what’s left so it doesn’t decay and feed algae under the cover. At dusk, dose a chlorine shock per label directions based on your pool volume; many owners target a temporary free-chlorine spike of roughly 10–12 ppm. Circulate overnight (8–12 hours) so the shock reaches every corner. If you prefer a non-chlorine oxidizer (MPS), follow the manufacturer’s dosage and still circulate thoroughly. Wait 24 hours and re-test to confirm the water is clear and the sanitizer level is stable before you cover.

Step 4: Add a Winter Algaecide (Optional but Helpful)

Polyquat 60 is a good winter companion: it doesn’t stain, it doesn’t foam, and it plays nicely with chlorine. Dose it after the shock has had a night to work, and run the pump another hour or two to distribute. Avoid copper-based products unless you’re prepared to manage potential staining on a light-colored liner.

Step 5: Decide Whether to Lower the Water

If you use a skimmer winter plate or a threaded skimmer plug, you can usually leave the water at normal height. That keeps the liner supported and reduces the chance of wind getting under the cover. If you’re not using a plate or plug, drop the level to 1–2 inches below the bottom of the skimmer so surface water can’t seep into the skimmer throat and freeze. Mesh covers let some precipitation through, so in very wet climates a slightly lower level can help prevent overflow.

Step 6: Protect Equipment and Lines from Freezing

Turn off power at the breaker. Remove the drain plugs on the pump and filter to let them empty completely, and crack open any unions so trapped pockets can drain. If you have a multiport valve on a sand or D.E. filter, set it to “Winterize” or between positions to take pressure off the diverter.

For plumbing, the gold standard is to blow out the lines from the equipment pad toward the pool using a low-pressure shop blower or a dedicated line blower; once air visibly bubbles from the returns and skimmer, install winter plugs on those fittings. If you cannot fully blow lines dry, add a manufacturer-approved pool-grade antifreeze to vulnerable lines as insurance. Do not use automotive antifreeze—it’s toxic and not designed for pools.

Bring small components—pressure gauges, pump lids, O-rings, the cartridge element—indoors for safe, dry storage. Lightly lube O-rings with a pool-safe silicone lubricant and store them in labeled bags.

Step 7: Install the Air Pillow

Inflate the air pillow to about 60–80% (you want a little give so it can compress without popping) and tether it to the pool rails so it sits near the center. The pillow absorbs ice expansion and creates a high spot so rain and snowmelt migrate to the edges, reducing cover sag and tear risk.

Step 8: Cover the Pool Correctly

Center the winter cover and draw it tight with the cable and winch. Add cover clips around the perimeter for extra grip—especially in windy areas. If you have heavy leaf fall, lay a leaf net over the winter cover now or add it after the big autumn drop; it makes mid-winter cleanups painless. Set an automatic cover pump on the center low point and route the discharge away from the pool wall to prevent wash-back.

Step 9: Final Checks and Documentation

Take a last reading of pH, alkalinity, and free chlorine and jot down the values along with the date you closed and the products you added. That log saves guesswork at opening. 

Step 10: Low-Effort Winter Maintenance

Even a “set-and-forget” close needs a glance now and then. Plan to check every 3–4 weeks: pump off standing water from the cover, confirm the cable tension, and re-center the pillow if wind has nudged it. After big storms, clear heavy snow or ice in stages—don’t stab or scrape the cover; let the pump handle meltwater and use a soft broom to nudge slush toward the intake.

Special Cases

Saltwater systems. Power down the chlorinator, remove the salt cell, and clean it per the manual if scale is present. Rinse, dry completely, and store the cell and control head indoors where it won’t freeze. Inspect O-rings and gaskets now so you’re not hunting leaks in April.

Soft-sided or inflatable pools. Most manufacturers recommend draining, cleaning, drying, and storing indoors. If you decide to leave it up in a mild climate, understand that vinyl can stiffen and age faster in cold weather. Be meticulous about cover pump use and wind protection.

Mild winter “soft close.” In parts of the South and on the West Coast, you can skip blowing lines and instead run a short daily circulation (for example, 2–4 hours during the coldest part of the night), maintain sanitizer and pH, and keep the cover tight with the pump running after rains. You’ll still follow the cleaning, balance, and shock steps above; you simply don’t have to fully winterize plumbing.

Common Mistakes

The big errors are all avoidable.

• Closing too early: Traps heat and nutrients under the cover, inviting algae.

• Skipping shock or covering right after shocking: Shortens sanitizer life and can bleach the liner.

• Forgetting to drain the pump and filter: Fastest path to a cracked housing.

• Letting water pool on the cover: Stretches fabric and rips seams—use an automatic cover pump.

• Over-inflating the air pillow: Leave some give so it can compress and do its job.

Quick Reference Targets

For fast checks, remember these numbers: pH 7.2–7.6, TA 80–120 ppm, CH 175–250 ppm for vinyl, water at or just below the skimmer depending on your plate/plug setup, air pillow at 60–80% inflation, and cover pump whenever you see standing water. Keep the water cold at closing (<60°F) and the cover tight all winter.

Conclusion

Winterizing an above-ground pool is simple when you stick to the basics: deep-clean, balance and shock, drain/protect equipment and lines, cover tightly, and check every few weeks. Do it when water stays below 60°F, and you’ll avoid freeze damage and spring algae—making opening day fast and stress-free.

FAQs

How far down do you drain your inground pool for winter?

If lines are blown and plugged: lower 3–6 in below the skimmer for solid covers; 12–18 in for mesh covers to allow rain/snow.

What month should you winterize your pool?

Whenever water stays below 60°F for a week. In the U.S.: North Sept–Oct, Mid Oct–Nov, South Nov–Dec (varies by climate).

What chemicals do I need to put in my pool to close it?

Balance pH/TA/CH, shock with chlorine (or non-chlorine oxidizer), and add Polyquat 60 algaecide. Optional: metal/sequestrant if needed.

Should you shock your pool before winterizing?

Yes. Shock at dusk 24–48 hours before covering and circulate well to oxidize contaminants.

Can I put chemicals in my pool without the pump running?

No. Run the pump to distribute evenly and avoid staining or localized damage; brush after dosing.

Can you pour shock directly into a pool?

Follow the label. Liquid: pour slowly in front of a return. Dry (cal-hypo/dichlor): broadcast with pump on and brush; pre-dissolve if directed.

How many days can a pool go without a pump?

In warm weather, avoid more than 1–2 days (algae risk). In cold, covered off-season it can be longer if chemistry is balanced.

Should the pump run when shocking the pool?

Yes. Run 8–12 hours (or overnight) to mix thoroughly and prevent bleaching spots.