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Winterization by Region

Climate-specific winterization strategies by USDA zone - drain depth conventions, skimmer protection methods, and regional best practices.

When to use: Need to understand which winterization method is appropriate for your specific climate and freeze risk.

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Winterization by Region

Climate-specific winterization strategies - drain depth, skimmer protection, and regional conventions

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Quick Regional Reference

Zones 1-4: Full winterization + Gizzmos + lower 12-18" below skimmer

Zones 5-6: Standard winterization + Gizzmos + lower 6-12" below skimmer

Zone 7: Partial winterization + bottles/antifreeze + lower 0-6" (optional)

Zones 8-9: Equipment protection + freeze guard + normal water level

Zone 10+: No winterization - normal year-round operation

Critical Regional Mistakes to Avoid

• NEVER use Zone 9 methods in Zone 6 climate (skimmer will crack - $800+ repair)
• NEVER drain pool completely in any zone (hydrostatic pressure damage)
• NEVER assume freeze guard alone protects equipment (power outage = freeze)
• NEVER skip secondary skimmer protection (both freeze equally)
• NEVER use mesh cover in Zone 1-4 without lowering water (overflow freezing)
• If moved from warmer climate: adopt local practices, not previous region's

Cover Type Selection by Climate

SOLID SAFETY COVER: Best for Zones 1-6. Blocks all debris, prevents evaporation, allows snow load (3,000+ lbs capacity). Requires cover pump for rain/melt. Cost: $1,200-$3,000. Lasts 10-15 years.

MESH SAFETY COVER: Good for Zones 3-7. Drains rain/snow automatically (no pump needed). Allows fine debris through. Requires higher closing FC due to debris. Cost: $800-$2,000. Lasts 12-15 years.

TARP COVER (Winter Grade): Budget option for Zones 5-8. Not safety-rated. Requires water bags/weights. Collects water (pump needed). Heavy debris risk in wind. Cost: $150-$500. Lasts 3-5 years.

NO COVER: Only practical in Zones 8-10. Requires weekly debris removal and higher chemical usage. Allows swimming on warm days. Works with freeze guard automation.

Determine Your Winterization Zone

Regional climate drives which winterization method is appropriate for your pool.

ZONE 1-4 (Northern): -20°F to 10°F winter lows - Michigan, Minnesota, Maine, Montana, North Dakota

ZONE 5-6 (Cold): 10°F to 25°F winter lows - Illinois, Ohio, Pennsylvania, New York, Massachusetts

ZONE 7 (Moderate): 25°F to 32°F winter lows - Virginia, Kentucky, Tennessee, Oklahoma, New Mexico

ZONE 8 (Mild): 32°F to 40°F winter lows - North Carolina, Arkansas, Texas Panhandle, Northern California

ZONE 9 (Rare Freeze): 40°F to 50°F winter lows - South Carolina, Georgia, Central Texas, Southern California

ZONE 10+ (Frost-Free): 50°F+ winter lows - South Florida, Hawaii, Southern California coast

Check USDA Plant Hardiness Zone Map for your specific location

Historical winter low temp matters more than average temp (one freeze can crack plaster)

Zone 1-4: Total Winterization (Harsh Freeze Climates)

Extreme climates require complete drainage, heavy antifreeze use, and robust covers.

WATER LEVEL: Lower to 12-18 inches below tile line (below skimmer mouth)

SKIMMERS: Remove skimmer baskets, install Gizzmo or ice compensator in each skimmer

Gizzmos expand to absorb ice pressure (prevents skimmer cracking - $800 repair)

Pour 1 quart antifreeze into each skimmer after installing Gizzmo

MAIN DRAIN: Close main drain valve, blow out main drain line completely

Add 2 quarts antifreeze to main drain line (pour through skimmer with MD valve open)

RETURNS: Remove return fittings (eyeball fittings), install winter plugs in wall returns

Blow out return lines with compressor at 15-20 PSI until only air exits

Add 1 cup antifreeze per return line after blow-out

DUAL SKIMMERS: Both skimmers need Gizzmos and antifreeze (don't skip secondary)

PLUMBING: Total line blow-out required - hire professional if not confident

COVER: Solid safety cover mandatory (mesh covers allow too much debris/water)

PILLOWS: Use air pillows or ice equalizers in center to absorb ice expansion

Pool will be completely closed November-April (5-6 months typical)

Zone 5-6: Standard Winterization (Cold Climates)

Traditional winterization with full drainage and freeze protection.

WATER LEVEL: Lower to 6-12 inches below tile line (just below skimmer)

SKIMMERS: Install Gizzmos or pour antifreeze-filled bottles into skimmers

Alternative to Gizzmo: 1-liter bottle filled with 50/50 antifreeze/water (floats, absorbs pressure)

Add 1 pint antifreeze to each skimmer after installing freeze protection

MAIN DRAIN: Blow out main drain line, add 1-2 quarts antifreeze

Some pools keep main drain valve open (equalizes pressure), others close it

RETURNS: Install threaded winter plugs (expanding rubber type recommended)

Blow out return lines thoroughly - any water left can freeze and crack pipe

Add 1/2 cup antifreeze per return after plugging

DUAL SKIMMERS: Primary and secondary both need Gizzmos (both will freeze)

COVER TYPE: Solid safety cover preferred, mesh acceptable with higher chemical dose

Mesh covers: Close at SLAM FC level (40% of CYA) due to debris accumulation

Solid covers: Standard closing FC (10-15 ppm) adequate

Pool closed November-April (4-5 months typical)

Zone 7: Partial Winterization (Moderate Freeze Risk)

Hybrid approach - protect plumbing but maintain water level options.

WATER LEVEL OPTION A: Lower to 4-6 inches below skimmer (if using mesh cover)

WATER LEVEL OPTION B: Maintain normal level (if using solid cover or no cover)

SKIMMERS: Skimmer guard/bottle method often sufficient (Gizzmos optional)

Pour 1 pint antifreeze into skimmer throat as insurance

If keeping water at normal level: float empty gallon jugs in skimmer (absorbs ice)

MAIN DRAIN: Usually left operational (valve open, no antifreeze needed)

If drain is deep (8+ feet): water at depth won't freeze

RETURNS: Plug returns below waterline, blow out if extended freeze forecast

Returns above waterline: blow out and plug (standard procedure)

DUAL SKIMMERS: Secondary skimmer can be left open if water level maintained

EQUIPMENT: Drain filter, pump, heater fully (freeze risk still significant)

COVER TYPE: Either solid or mesh works - solid preferred for chemistry stability

WINTER OPERATION OPTION: Some pools run freeze protection mode (pump cycles at 32°F)

Freeze guard requires winterizing heater only (pump/filter stay operational)

Pool closed/open: Variable (some run all winter with freeze guard, others close Dec-March)

Zone 8: Minimal Winterization (Occasional Freeze)

Light winterization with equipment protection and freeze-guard readiness.

WATER LEVEL: Keep at normal level (mid-skimmer) - no drainage needed

SKIMMERS: Leave operational for freeze guard system, OR

If closing completely: pour antifreeze into skimmer (no Gizzmo needed)

MAIN DRAIN: Leave operational - no winterization required

RETURNS: Leave operational if running freeze guard, plug only if closing completely

EQUIPMENT WINTERIZATION: Drain heater only (heat pump and gas)

Pump and filter stay ready for freeze guard operation

FREEZE GUARD AUTOMATION: Mandatory for Zone 8 if closing pool

Set freeze guard to activate at 38-40°F (water temp, not air temp)

Pump will run 24/7 during freeze events (moving water doesn't freeze)

COVER: Optional - many Zone 8 pools don't use winter cover

If covering: mesh cover acceptable (allows drainage from rain/snow)

CHEMISTRY: Maintain FC at 3-5 ppm all winter (test monthly)

Pool semi-operational: Can swim on warm days (60°F+ air temp)

Heating optional but expensive (heat pump works, gas wasteful)

Closing period: December-February (if at all) - many stay open year-round

Zone 9: Maintenance Mode (Rare Freeze Events)

Pool stays operational with normal maintenance and freeze-event preparedness.

WATER LEVEL: Normal operating level year-round (mid-skimmer)

SKIMMERS: Fully operational - no winterization needed

MAIN DRAIN: Fully operational - no winterization needed

RETURNS: Fully operational - no winterization needed

EQUIPMENT: All equipment stays operational (no winterization)

HEATER: Heat pump can run all winter (cost-effective in Zone 9)

Gas heater rarely needed except for spa heating

FREEZE EVENT PREPARATION: Keep antifreeze on hand for rare freezes

If hard freeze forecast (below 28°F for 6+ hours): run pump continuously

Optional: pour 1 pint antifreeze into skimmer as insurance (rare)

AUTOMATION: Freeze guard recommended but not critical

Set freeze guard to 36-38°F activation (insurance against unexpected cold)

COVER: Usually no cover used - pool swimmable 9-11 months per year

If covering for cleanliness: solar cover or leaf net (not winterization)

CHEMISTRY: Normal maintenance schedule (test weekly, shock as needed)

SWIMMING SEASON: October-June typical, year-round in coastal areas

Heating season: November-March (heat pump provides comfortable 80-82°F)

Zone 10+: Year-Round Operation (Frost-Free)

No winterization - normal pool operation continues all year.

NO WINTERIZATION REQUIRED - maintain pool normally year-round

WATER LEVEL: Normal operating level always (mid-skimmer)

SKIMMERS: Operational 365 days per year

MAIN DRAIN: Operational 365 days per year

RETURNS: Operational 365 days per year

EQUIPMENT: No winterization - normal maintenance schedule

Filter cleanings: cartridge every 4-6 weeks, DE/sand as pressure indicates

HEATING: Optional solar heating provides free warmth in 'winter'

Heat pumps rarely needed (ambient temp adequate for comfortable swimming)

Gas heating very rare (used only for spas or extreme comfort preference)

CHEMISTRY: Weekly testing and maintenance (no seasonal variation)

Slightly lower chlorine demand in winter due to less sunlight/heat

COVER: Not used except for energy conservation or debris prevention

Solar covers reduce evaporation and heat loss (minimal benefit in Zone 10+)

SWIMMING: Year-round swimming typical - pool is primary recreation feature

Busiest months: June-August, but Dec-Feb still see regular use

SEASONAL TASKS: Deep cleaning in spring, equipment inspection in fall

Skimmer Protection Methods by Climate

Detailed comparison of skimmer winterization techniques and regional appropriateness.

GIZZMO METHOD (Best for Zones 1-6): Threaded plastic tube that screws into skimmer

Absorbs ice expansion, prevents skimmer cracking (most effective method)

Cost: $8-12 each, reusable for 3-5 years, mandatory in harsh climates

BOTTLE METHOD (Good for Zones 5-7): Empty bottles or sealed antifreeze jugs in skimmer

2-liter soda bottle works, or 1-gal jug partially filled with antifreeze

Less reliable than Gizzmo but adequate for moderate climates

ANTIFREEZE-ONLY METHOD (Zones 7-8): Pour antifreeze into skimmer, no physical device

1 quart per skimmer, displaces water below freeze line

Only works if freeze risk is low (occasional, not sustained)

FLOAT METHOD (Zones 8-9): Float sealed jugs/bottles in skimmer to absorb pressure

Minimal protection - for insurance against unexpected freeze only

OPERATIONAL METHOD (Zones 9-10): Skimmer stays operational with freeze guard

Pump circulates water preventing freeze (moving water doesn't freeze)

DUAL SKIMMER CONSIDERATIONS: Both skimmers need equal protection

Common mistake: protecting primary skimmer only (both freeze simultaneously)

If one skimmer deeper than other: shallow skimmer is higher priority

Water Level Depth Conventions & Rationale

Understanding why different regions lower water to different depths.

BELOW RETURNS (18-24 inches below tile): Zones 1-3 only

Extreme climates where ice can reach 12+ inches thick

Protects wall returns, skimmers, and tile line from ice pressure damage

BELOW SKIMMER (12-18 inches below tile): Zones 4-5 standard practice

Prevents skimmer freeze even if Gizzmo fails

Ice thickness rarely exceeds 8-10 inches, so skimmer safe when submerged

JUST BELOW SKIMMER (6-12 inches below tile): Zones 5-6 typical

Protects against skimmer freeze while minimizing water removal

Requires reliable Gizzmo or bottle method (water still near skimmer)

SLIGHTLY BELOW TILE (4-6 inches below): Zone 7 with mesh cover

Mesh allows rain/snow to drain, preventing overflow and freeze

Not freeze protection - Gizzmo/antifreeze provides that

NORMAL LEVEL (mid-skimmer): Zones 7-10

No drainage needed if solid cover used or freeze guard operational

Easier spring startup (no refilling required)

HYDROSTATIC PRESSURE CONSIDERATION: Never drain pool completely

Groundwater pressure can pop plaster pools out of ground (very expensive)

Vinyl liners shrink and wrinkle permanently if pool drained

Fiberglass pools can crack or shift if drained (groundwater buoyancy)

Common Questions

I'm between two zones - which method should I use?

Always use the colder zone's method. Winterization is insurance - over-preparing is safer than under-preparing. One unexpected cold snap can cause $1,000+ damage. Cost difference between zone methods is minimal ($20-30 in materials).

Can I use a Zone 5 method in Zone 7 to be extra safe?

Absolutely. More protection never hurts. Common approach: use Gizzmos in Zone 7 even though bottles work. Or lower water more than necessary. Only downside is slightly more effort and materials cost (~$30-50). Peace of mind is worth it.

What if we get an unusual freeze in Zone 9?

Keep pool antifreeze and Gizzmos on hand for emergency use. Monitor weather forecasts. If hard freeze (below 28°F for 6+ hours) is forecast: run pump continuously, pour antifreeze into skimmers (1 quart each), and optionally lower water 4-6 inches quickly with submersible pump.

My pool builder says not to lower water - but I'm in Zone 5. Who's right?

If builder is from warmer climate or unfamiliar with harsh winters, their advice may not apply. Consult local pool service companies familiar with your specific area. Regional conventions exist because they work. In Zone 5, lowering water 6-12" below skimmer is standard practice.

How much does it cost to fix a cracked skimmer from freeze?

Skimmer replacement: $400-$1,200 depending on pool type and accessibility. Plaster pools require jackhammering deck (highest cost). Vinyl pools require liner removal. Fiberglass pools easier but still $400-600. A $10 Gizzmo prevents this entirely.

What's the difference between a Gizzmo and ice compensator?

Same thing, different brands. "Gizzmo" is a brand name that became generic (like Kleenex). Ice compensator, freeze plug, and skimmer guard all describe the same product: a compressible tube that absorbs ice expansion in skimmers. Any brand works equally well.

Common Regional Examples

Minneapolis, MN (Zone 4):

Full winterization mandatory. Lower water 18" below tile. Gizzmos in all skimmers. Blow out all lines completely. Add 3-4 gallons antifreeze total. Solid cover required (snow load heavy). Closed November-April.

Chicago, IL (Zone 5):

Standard winterization. Lower water 12" below tile. Gizzmos standard practice. Blow out all lines. 2-3 gallons antifreeze. Mesh or solid cover both work. Closed November-April.

Philadelphia, PA (Zone 7):

Partial winterization. Lower water 6" or maintain normal level with solid cover. Gizzmos or bottle method. Blow out lines. 1-2 gallons antifreeze. Mesh cover popular. Closed December-March.

Dallas, TX (Zone 8):

Minimal winterization. Normal water level. Antifreeze in skimmers as insurance. Drain heater only. Freeze guard automation recommended. No cover common. Semi-operational November-February.

Atlanta, GA (Zone 8):

Light winterization or freeze guard mode. Normal water level. Pour antifreeze into skimmers. Drain heat pump. Mesh cover or no cover. Can swim 9-10 months. Brief closure January-February if at all.

Phoenix, AZ / Southern CA / South FL (Zone 10):

No winterization. Year-round operation. Normal maintenance. Swim 12 months. Heat optional (solar common). No special procedures needed.

Checklist

1Determine your winterization zone (1-4 harsh, 5-6 cold, 7 moderate, 8-9 mild, 10+ frost-free).
2Zone 1-4: Total winterization - lower 12-18" below skimmer, Gizzmos mandatory, solid cover.
3Zone 5-6: Standard winterization - lower 6-12" below skimmer, Gizzmos standard, blow out lines.
4Zone 7: Partial winterization - lower 0-6" optional, bottle/antifreeze method, hybrid approach.
5Zone 8: Minimal winterization - normal water level, freeze guard automation, drain heater only.
6Zone 9: Maintenance mode - operational with freeze event preparation, antifreeze on hand.
7Zone 10+: Year-round operation - no winterization needed, normal maintenance continues.
8Understand skimmer protection by climate - Gizzmo vs bottle vs antifreeze-only methods.
9Learn water level depth rationale - hydrostatic pressure, ice thickness, cover type considerations.

Related Playbooks

Winter Closing Checklist

Protect your pool through the off-season with nutrient control, equipment prep, and freeze safeguards.

Winterizing In-Floor Cleaning Systems

Protect pop-up heads, water distribution valves, and booster pumps from freeze damage with proper blow-out and antifreeze procedures.

Winterizing Pool Heaters

Comprehensive winterization for gas, electric, heat pump, solar, and hybrid heaters - prevent $1,500-$4,000 freeze damage.