How to Winterize a Hot Tub (or Keep It Running Safely in Winter)

If you live in a climate where temperatures drop below freezing, learning how to winterize a hot tub can prevent cracked pipes, damaged pumps, and costly spring repairs. Water expands roughly 9% when frozen—if trapped inside jets, heaters, or manifolds, that expansion can cause serious structural damage.

You have two options:

• Full winterization (shutdown)
• Run your hot tub safely through winter

This guide explains both paths clearly so you can choose the right method for your climate and usage.

Explore our full line of premium outdoor spas designed for cold-climate performance.

Option 1: Full Winterization (Shut Down the Spa)

Choose this method if:

• You won’t use the spa for 60+ days
• You can’t monitor power or water levels
• You want zero winter energy costs

Step 1: Turn Off Power

• Shut down at the control panel
• Switch OFF the GFCI breaker
• Confirm display is completely off
• Never work on plumbing with live power.

Step 2: Drain the Hot Tub

• Attach a garden hose to the drain spigot
• Or use a submersible pump for faster draining
• Remove all standing water with a wet/dry vacuum
• Do not drain during an active hard freeze.

Step 3: Remove & Clean Filters

• Remove filter cartridges
• Clean thoroughly
• Store indoors

Step 4: Open Equipment Bay & Drain Plumbing

• Remove front access panel
• Loosen pump unions
• Remove pump drain plugs
• Allow all internal water to escape

Even after draining the shell, pumps and heater canisters still hold water.

Step 5: Blow Out All Plumbing Lines (Critical)

• Using a wet/dry shop-vac:
• Blow from the filter well (suction side)
• Blow through each jet face
• Rotate diverter valves while purging
• Clear waterfalls and air lines
• Alternate blow → vacuum

This is the most important step to prevent freeze damage.

Step 6: Add RV/Marine Antifreeze (Optional)

• For deep-freeze climates (below 10°F / −12°C):
• Use propylene glycol RV/Marine antifreeze only
• Add small amounts into low points and jets
• Never use automotive antifreeze

Many moderate climates do not require antifreeze if purge is thorough.

Step 7: Dry & Seal

• Vacuum equipment bay
• Wipe shell dry
• Close drain valves
• Secure cover tightly
• Add cover cap and wind straps

A sagging cover allows snowmelt to re-enter plumbing and refreeze.

Option 2: Keep Your Hot Tub Running Through Winter

Many owners safely enjoy winter soaking. This works best when:

• You can check the spa weekly
• Power supply is reliable
• Freeze-protection mode is verified

Our cold-climate spa models are engineered with advanced insulation and freeze-protection systems.

Pre-Winter Preparation

• Drain and refill with fresh water
• Clean or replace filters
• Balance water chemistry
• Shock system

Starting winter with clean water reduces maintenance and heater strain.

Enable Freeze Protection

Most modern hot tubs automatically cycle pumps when temperatures drop.

Confirm your freeze-guard mode is enabled and functioning. Never assume it works—verify it.

Reduce Heat Loss

Biggest ROI improvements:

• Tight, flat cover (replace waterlogged foam cores)
• Add waterproof cover cap
• Use floating thermal blanket
• Install windbreak
• Keep air controls closed when not in use

Weekly 5-Minute Winter Checklist

• Check water level
• Inspect cover seal
• Test sanitizer & pH
• Rinse filters (every 2–3 weeks)
• Look for cabinet moisture or leaks

Consistent quick checks prevent emergency failures.

Emergency Plan: Power Outage During Freeze

If power fails during extreme cold:

• Do not drain immediately
• Open equipment bay
• Place thermostatic space heater safely inside cabinet
• Insulate cabinet exterior
• Restore power ASAP

Frozen plumbing happens most often during outages.

When Should You Winterize?

• Mild climates: Before consistent night freezes
• Cold climates: Before first hard freeze (below 23°F / −5°C)
• Mountain regions: Plan early due to rapid temperature swings

Spring Startup After Winterization

1. Close drains and reinstall plugs
2. Tighten pump unions (hand snug only)
3. Vacuum out antifreeze (if used)
4. Refill through filter well
5. Restore power
6. Check for leaks
7. Balance water
8. Shock before first soak

Common Winterization Mistakes

1. Draining without blowing out lines
2. Using automotive antifreeze
3. Leaving power on after draining
4. Forgetting waterfalls or air lines
5. Allowing snow to sag the cover
6. Not verifying freeze protection

Should You Winterize or Run Your Hot Tub?

If you cannot monitor power or check the spa weekly, full winterization is safest.

If you enjoy winter soaking and have reliable power, keeping the spa running is safe and convenient with proper insulation and monitoring.

Either method works—what matters is consistency and preparation.