SC By SCWS Team | February 2, 2026 | 10 min read
How to Winterize a Well Pump House
A single hard freeze can destroy thousands of dollars worth of well equipment in hours. While San Diego County's coastal and valley areas rarely see freezing temperatures, mountain communities like Julian, Mount Laguna, Palomar Mountain, and Pine Valley routinely experience winter freezes—sometimes severe. Whether you live in these areas year-round or own a cabin that sits empty during winter, protecting your well system from freeze damage is essential.
⚠️ Freeze Damage Is Expensive
- • Burst pressure tank: $800-$2,500 to replace
- • Cracked jet pump housing: $1,500-$3,000
- • Broken pipes and fittings: $500-$2,000+
- • Water damage from flooding: Potentially catastrophic
- • Prevention costs a fraction of repairs
Understanding Freeze Risk
Not all parts of your well system face equal freeze risk:
🎯 Freeze Risk by Component
High Risk
Exposed Pipes
Any pipe above ground or in unheated space freezes first
High Risk
Jet Pump
Above-ground pumps contain water that can freeze and crack housing
Medium Risk
Pressure Tank
Large volume takes longer to freeze but damage is severe
Medium Risk
Pressure Switch
Small tube can freeze and become blocked or damaged
Lower Risk
Wellhead
Below-ground pitless adapter provides protection
Protected
Submersible Pump
Deep in well where temperature stays above freezing
Complete Winterization Checklist
Step 1: Inspect and Seal the Pump House Structure
Your first line of defense is the building itself:
- Check for gaps: Inspect where pipes enter/exit, around vents, at door frames, and where walls meet foundation
- Seal openings: Use caulk for small gaps, expanding foam for larger ones
- Repair damage: Fix any broken siding, cracked windows, or damaged roofing
- Check the door: Ensure it closes tightly; add weatherstripping if needed
- Vent carefully: Some ventilation is needed, but large vents allow cold air in
💡 Don't Forget Vents
While sealing, remember that pump houses need some ventilation for motor cooling and moisture control. Use adjustable vents that can be closed during extreme cold or install small, insulated vents at opposite ends for air circulation without major heat loss.
Step 2: Insulate Walls and Ceiling
If your pump house isn't already insulated:
- Walls: Add fiberglass batts, rigid foam, or spray foam insulation
- Ceiling: Don't forget overhead—heat rises and escapes through uninsulated roofs
- Floor: If raised off ground, insulate underneath or skirt the perimeter
- Minimum R-value: R-13 walls, R-19 ceiling recommended for mountain areas
Step 3: Insulate All Exposed Pipes
Every inch of exposed pipe is a freeze point:
- Foam pipe insulation: Easy to install, available in various diameters—use tape or cable ties to secure
- Fiberglass wrap: More flexible for irregular fittings
- Don't skip fittings: Valves, elbows, and tees are vulnerable—wrap them too
- Check underground-to-above-ground transition: Where pipe exits ground is often forgotten
Step 4: Install Heat Tape/Heat Cable
For areas that get truly cold, insulation alone may not be enough:
- Self-regulating heat tape: Adjusts output based on temperature (recommended)
- Constant-wattage heat tape: Less expensive but requires thermostat
- Installation: Wrap in spiral pattern or run straight along pipe; secure with tape
- Cover with insulation: Heat tape works best when insulated over the top
- GFCI protection: Always use GFCI-protected outlet for safety
⚠️ Heat Tape Safety
- • Use only UL-listed products designed for pipe heating
- • Never overlap heat tape—can cause overheating/fire
- • Inspect annually for damage before cold season
- • Don't use on plastic pipes unless tape is rated for plastic
Step 5: Add a Heat Source
For pump houses in areas with extended freezing periods:
| Heat Source | Pros | Cons | Cost |
|---|---|---|---|
| Thermostat-Controlled Heater | Efficient, turns on only when needed | Requires electricity | $50-$150 |
| Heat Lamp | Inexpensive, simple | Fire risk if improperly installed, constant electricity | $20-$50 |
| Ceramic Heat Emitter | No light, safer than heat lamp | Still a fire risk near combustibles | $25-$60 |
| Oil-Filled Radiator | Safe, thermostatic, even heat | Higher electricity use, larger | $40-$100 |
The goal is to keep interior temperature above 40°F (4°C)—you don't need it warm, just above freezing.
Step 6: Insulate the Pressure Tank
Your pressure tank holds the most water and is expensive to replace:
- Water heater blanket: Works great for pressure tanks
- Rigid foam boards: Can be cut and taped around tank
- Fiberglass blanket: Wrap and secure with straps
- Don't cover control valve: Leave pressure gauge and switch accessible
Step 7: Protect the Wellhead
If your well doesn't have a pump house and the wellhead is exposed:
- Well cap insulation: Insulate around the well casing at ground level
- Mound mulch: Pile mulch or straw around the wellhead
- Insulated well cover: Install a protective insulated cover or enclosure
- Heat tape: Wrap any exposed piping at the wellhead
Winterizing for Vacant Properties
If your property will be unoccupied during freezing weather, take extra steps:
Complete Drain-Down Method
- Turn off power to well pump at the breaker
- Open the drain on the pressure tank and let it empty completely
- Open all faucets inside the house—hot and cold
- Flush toilets and hold handles to drain tanks
- Open hose bibs and outdoor faucets
- Use compressed air to blow water from lines (optional but thorough)
- Pour RV antifreeze into drain traps, toilet bowls, and toilet tanks (not regular antifreeze—it's toxic)
- Leave faucets slightly open to allow for any remaining water expansion
✅ RV Antifreeze Is Safe
RV (pink) antifreeze is propylene glycol-based and non-toxic. It's safe for plumbing systems and won't harm septic systems. Never use automotive antifreeze (green/orange)—it's toxic to humans and pets.
For Jet Pumps
Jet pumps require additional attention since they hold water in the pump housing:
- Drain the pump completely using the drain plug
- Remove and drain any inline strainers or filters
- Consider adding RV antifreeze to the pump housing through the priming port
- Cover the pump with an insulated blanket
During Extreme Cold Snaps
When temperatures drop particularly low, add these measures:
Keep Water Moving
Moving water is harder to freeze than standing water:
- Let a faucet drip: A slow, steady drip keeps water flowing through the system
- Choose a faucet at the end of the line: This moves water through the longest path
- Use the coldest side: Usually cold water lines are more vulnerable
Check Your Pump House
During cold spells, inspect daily:
- Is the heater running?
- Is heat tape warm to the touch?
- Is the thermometer above 40°F?
- Any frost visible on pipes?
- Water pressure normal at house?
What If Pipes Do Freeze?
If you discover frozen pipes, act quickly but carefully:
✓ Safe Thawing Methods
- • Hair dryer on low/medium heat
- • Heat lamp at safe distance
- • Space heater nearby (not touching)
- • Hot towels wrapped around pipe
- • Heating pad wrapped around pipe
✗ Never Use These Methods
- • Open flame (torch, candle, lighter)
- • Kerosene or propane heaters in enclosed space
- • Boiling water poured on cold pipes
- • Any method that could cause fire or steam burst
Important: Before thawing, locate your water shut-off. If a pipe has already burst, you'll need to shut off water immediately when it thaws to prevent flooding.
San Diego Mountain Communities: Local Considerations
If you're in one of San Diego County's mountain communities, here are specific considerations:
Julian / Santa Ysabel
4,200-4,500 ft elevation. Regular freezes Dec-Feb. Plan for occasional single-digit temps.
Mount Laguna
5,500-6,000 ft elevation. Coldest in county. Snow common. Full winterization essential.
Palomar Mountain
5,500+ ft elevation. Significant snow and cold. Many properties are seasonal—drain-down recommended.
Pine Valley / Campo
3,500-4,000 ft elevation. Periodic hard freezes. Basic winterization usually sufficient.
Frequently Asked Questions
At what temperature do well pumps freeze?
Well pump equipment can freeze when temperatures drop below 32°F (0°C) for extended periods. Above-ground components like pressure tanks, exposed pipes, and jet pumps are most vulnerable. Submersible pumps in the well are protected by ground temperature.
How do I keep my well pump from freezing?
Key protection methods include: insulating the pump house structure, wrapping exposed pipes with heat tape, insulating all exposed piping, using a safe heat source inside the pump house, sealing air gaps, and keeping a small water flow during extreme cold.
Should I leave a faucet dripping to prevent well freeze?
A slow drip can help prevent pipe freezing by keeping water moving, but it's not a complete solution. Use it as a supplement to insulation and heating, not as your primary protection.
What happens if my well pressure tank freezes?
A frozen pressure tank can crack or rupture, potentially destroying the tank ($800-$2,500 to replace). Even if it doesn't burst, freeze damage can compromise the bladder. Water expands when frozen, creating tremendous pressure.
Do I need to winterize if I have a submersible pump?
The submersible pump itself is protected underground. However, the above-ground components still need protection: pressure tank, pressure switch, piping from wellhead to house, and any exposed wellhead equipment.
How do I winterize a well for a vacation home?
For unoccupied homes: turn off power to well pump, drain the pressure tank completely, open all faucets, use compressed air to blow out remaining water, add RV antifreeze to traps and toilet bowls, and insulate exposed equipment.
Need Help Winterizing Your Well System?
Whether you need professional winterization, freeze damage repair, or want to install permanent freeze protection, we can help. We serve well owners throughout San Diego's mountain communities including Julian, Mount Laguna, Palomar Mountain, Pine Valley, and surrounding areas.
