How to Winterize Your Inground Pool: Complete Step Guide

Tools & Supplies Needed

Find on Amazon: Taylor K-2006 Pool Test Kit , Winter Pool Chemical Kit , Submersible Pool Pump , Pool Winter Cover

Quick Answer

Proper winterization protects your inground pool investment from freeze damage and makes spring opening easier. The process involves balancing water chemistry, thorough cleaning, lowering water levels, adding winterizing chemicals, protecting equipment, and installing a winter cover. Start this process 2-3 weeks before your first expected freeze.

Step-by-Step Winterization Process

Phase 1: Water Chemistry Balance (1-2 weeks before closing)

1. Test and balance pH: Adjust pH to 7.4-7.6 using muriatic acid to lower or sodium carbonate to raise. Use a reliable test kit like Taylor K-2006 for accurate readings.
2. Adjust Total Alkalinity: Target 80-120 ppm for most pools. Add sodium bicarbonate if low, or muriatic acid if high (this will also lower pH).
3. Set Calcium Hardness: Aim for 200-300 ppm. Add calcium chloride if too low. High calcium requires partial water replacement.
4. Stabilizer levels: Ensure CYA is 30-50 ppm. Add cyanuric acid if needed (1 lb per 3,000 gallons raises CYA by approximately 10 ppm).
5. Shock the pool: Add liquid chlorine to achieve 10-12 ppm free chlorine. Run filtration continuously until FC drops to 3-5 ppm, indicating organic matter is oxidized.

Phase 2: Deep Cleaning (1 week before closing)

1. Brush all surfaces: Scrub walls, steps, and floor thoroughly to remove biofilm and algae. Pay special attention to corners and crevices.
2. Vacuum to waste: Remove all debris from pool bottom. Don't backwash the filter yet - you want maximum filtration during final cleaning.
3. Clean waterline: Use pool tile cleaner to remove scum line and calcium deposits that can harbor bacteria over winter.
4. Skim and net debris: Remove all floating leaves, insects, and organic matter that could decompose over winter.
5. Run filter 24/7: Operate filtration continuously for 48-72 hours after cleaning to polish water clarity.

Phase 3: Equipment Preparation

1. Backwash and clean filter: For sand filters, backwash thoroughly. For cartridge filters, remove and clean or replace cartridges. For DE filters, backwash and remove grids for cleaning.
2. Lower water level: Reduce water to 4-6 inches below skimmer opening for mesh covers, or 12-18 inches for solid covers. Use submersible pump if needed.
3. Drain skimmer lines: Remove skimmer baskets and use shop vacuum or compressor to blow water from lines. Add RV antifreeze to skimmer if in freeze-prone area.
4. Winterize return lines: Install return line plugs after blowing lines clear. Some systems require removing return fittings entirely.
5. Drain main drain line: If possible, blow this line clear and plug. In some configurations, you'll leave this line flooded but add antifreeze.

Phase 4: Equipment Winterization

1. Pump winterization: Remove drain plugs from pump housing and motor (if applicable). Store plugs in pump basket. Tilt pump to drain completely.
2. Filter system: Remove drain plugs from filter tank and multiport valve. For cartridge systems, remove all cartridges and drain housing completely.
3. Heater preparation: Turn off gas supply and electrical power. Remove drain plugs and follow manufacturer's winterization procedures. Some require professional service.
4. Salt chlorine generators: Remove cell and store indoors, or follow manufacturer's winter procedures. Most require removing flow sensor and control box batteries.
5. Automatic cleaners: Remove from pool, clean thoroughly, and store indoors. Drain all water from cleaner and hoses.

Phase 5: Winter Chemical Treatment

1. Add winterizing chemicals: Use winter chemical kits sized for your pool, or add individually: algaecide (non-metallic polymer type), enzyme clarifier, and stain preventer.
2. Final chlorine adjustment: Add liquid chlorine to achieve 3-5 ppm FC. This provides initial sanitization but won't last all winter.
3. Optional clarifier: Add polyaluminum chloride-based clarifier to help settle fine particles before cover installation.
4. Circulate chemicals: Run pump for 2-4 hours to distribute all winterizing chemicals evenly throughout the pool.

Phase 6: Final Steps

1. Install winter cover: For safety covers, ensure all springs and straps are properly tensioned. For solid covers, ensure proper water bags or attachment method.
2. Disconnect and store equipment: Remove pump, filter, and other equipment if recommended for your climate. Store in dry, protected area.
3. Final equipment shutdown: Turn off all electrical circuits at breaker panel. Remove or protect any electronic controls from moisture.
4. Document chemical levels: Record final test results for reference during spring opening.

Critical Timing and Climate Considerations

Timing is crucial: Begin this process 2-3 weeks before your first expected hard freeze. Rushing winterization often leads to incomplete chemical balancing or equipment damage.

Regional variations: Warmer climates may not require complete equipment removal, while extreme cold regions need additional antifreeze protection and equipment storage.

Common Winterization Mistakes to Avoid

• Closing with poor water chemistry - this leads to staining and algae problems
• Insufficient water removal from equipment - causes expensive freeze damage
• Adding chlorine tablets or cal-hypo shock - these can damage surfaces over winter
• Forgetting to remove cartridge filters - they can freeze and crack
• Improper cover installation - leads to debris accumulation and cover damage

Safety Warning: Always turn off electrical power before working on pool equipment. Use proper ventilation when adding chemicals, and never mix different chemical products.