Well pumps · winter
Freeze protection for well houses and pressure tanks
A buried well line below the frost line rarely freezes. What freezes is everything above ground: the pressure switch and its small sensing tube, the gauge, the tank tee, and any pipe in an unheated well house, crawlspace, or garage. A frozen pressure switch can leave a house without water — or crack fittings and flood the space when it thaws.
Bottom line
Seal drafts and insulate first, then add thermostatically controlled heat rated for the space, and put a temperature alert where you will see it.
Use heat cable only as the maker directs, on a GFCI-protected outlet, and keep any heater well clear of combustibles. Have a licensed electrician add circuits or outlets.
Fire safety
Improvised heat — open heat lamps, old space heaters, or heat cable wrapped over itself when the maker forbids it — is a common cause of well-house fires.
Use equipment listed for the location (damp or wet spaces included), follow the clearances on the label, and never run heat off an extension cord as a permanent fix.
What is most at risk
- Pressure switch and sensing tube. The small nipple or tube under the switch holds a little water and freezes first. Once ice forms, the switch cannot read pressure. See replacing a 40/60 pressure switch.
- Gauge, tank tee, and drain valve. Small, exposed fittings with little water mass.
- Pressure tank. Tanks hold more water and freeze later, but a frozen tank can split or damage the diaphragm. See pressure tank precharge.
- Exposed pipe and the well cap area. Above-grade pipe in a well house, crawlspace, or along an outside wall.
Layer the protection
| Layer | What to do | Notes |
|---|---|---|
| 1. Seal and insulate | Close gaps around doors, vents, and pipe penetrations; insulate walls, ceiling, and exposed pipe | Leave room to service the tank, switch, and wiring |
| 2. Thermostatic heat | A heater rated for the space with a built-in thermostat that holds the room above freezing | Follow label clearances; electrician for a dedicated circuit |
| 3. Heat cable on exposed pipe | Self-regulating or thermostat-controlled cable installed per the instructions, then insulated over if the maker allows | GFCI outlet; do not overlap or cover unless the product is rated for it |
| 4. Alerts | A low-temperature or leak alert you will actually see, plus a thermometer you can read at a glance | Wi-Fi alerts fail in an outage — check in person during long cold snaps |
| 5. Drain-down when vacant | If the property sits empty in winter, shut off pump power and drain the tank and exposed lines | Have a well contractor show you the right sequence for your system |
If it already froze
- Shut off power to the pump at the breaker so it does not run against a frozen switch or blocked line.
- Warm the space, not the part. Raise the room temperature with a listed heater or a hair dryer on low. Never use an open flame or torch on fittings, plastic, or near wiring.
- Look for cracks before restoring power. Check the switch, gauge, tank tee, and fittings for splits or drips.
- Restore power and watch. The pump should build to cut-out pressure and shut off normally. If it runs and runs, or the pressure will not build, stop and call a pro — see low water pressure on a well.
When to call a pro
- You need a new circuit, outlet, or hard-wired heater — use a licensed electrician.
- The pump, switch, or tank was damaged by freezing.
- The pitless adapter or buried line froze, which usually means a depth or installation problem.
- You want to relocate the tank and controls into heated space.
Getting help
Use a licensed electrician for heat and circuits and a licensed well contractor for freeze damage to the pump, tank, or piping. If freezing took out the pump or controls, R.E. Merrill & Associates is a Grundfos dealer and has handled industrial and municipal pumps and fluid systems since 1987 — contact R.E. Merrill & Associates about Grundfos SQ / SQE replacements and controls.
Related across the site
- Leak sensors for the basement, softener, and well tank — where to put sensors around the tank
- Replacing a softener brine float — if a softener shares the space
Sources
- Manufacturer instructions for pressure switches, pressure tanks, and pipe heat cable — freeze warnings, GFCI requirements, overlap and insulation rules, and heater clearances.
- Grundfos residential well pump literature — power-off before service and system protection guidance.