Can my well pump freeze?

The pump can't freeze. Everything above it can.

Groundwater in New Jersey sits around 50 degrees year round, and it stays there in January. A submersible pump lives down in that water, hundreds of feet below the frost line, and no air temperature on your porch reaches it. When somebody tells us their well pump froze, the pump is fine and something between the wellhead and the faucet stopped the water.

That distinction decides the whole day. A frozen line is a thaw and maybe a fitting. A ruined pump is a rig, a crew and hundreds of feet of pipe out of the ground. The two get confused constantly in a cold snap, and the confusion is expensive in both directions: people replace pumps that were never broken, and people run pumps into ice until they break them.

One real exception. An above ground jet pump isn't down the well. It sits in your basement, garage or pump house breathing the same air you are, and it freezes exactly like any other plumbing. If you've got a jet pump, the pump genuinely is on the list of things that can freeze.

Where the water actually freezes

Ice forms where water sits still in air that's below freezing. That's the entire rule, and it puts every candidate above ground or close to it. In rough order of how often we find them.

The pattern worth remembering is simple. If you can reach it without a rig, it can freeze. If it's down the casing, it can't.

• The pressure tank, the tank tee and the switch. A crawl space, an unheated basement corner, a garage, or a utility closet on an outside wall. A tank holding water in 15 degree air is the single most common freeze call we get, and the tank tee with its nest of small fittings freezes before the tank does.
• An exposed jet pump. In an unheated basement or a pump house, the volute holds water and the casting cracks. A small outbuilding with a bad door seal or a burned out heat lamp turns into a chest freezer in one night.
• The buried line between the well and the house. Below the frost line it's fine forever. Cut shallow because the trench hit rock, run through a vented crawl space, or crossing under a stoop or a slab, and it isn't. This is the most common one in older lake houses where the line was put in for a summer cottage.
• The pitless adapter. The fitting that takes water out through the side of the casing, normally set four to six feet down, well under the frost line. Set shallow on a well where the driller hit ledge, or exposed because grade got cut away later for a driveway or a patio, and the water sitting in it freezes.
• Hose bibbs and the line to an outbuilding. A hose left connected in November holds water against the sill cock and splits it in January. The buried feed to a barn, a garage or a guest cottage is the line nobody remembers until it fails.
• The well cap itself. A cracked cap or a missing vent screen lets cold air and snowmelt straight down the casing. It's rarely the freeze point on its own, but it's the reason ice forms higher up the casing than it should.

Telling a freeze from a pump failure

A few things separate the two before anyone touches a tool. A freeze arrives with the weather. If the water quit during the first hard night after a mild week, or the morning after the wind picked up, weather is the first suspect. A pump failure has no relationship to the thermometer.

Watch the gauge on the tank tee. With a frozen line downstream of the tank, the pump builds pressure normally and the gauge climbs to cut-out and sits there, but nothing comes out of any faucet. That's a plug, not a pump. With a dead pump, the gauge falls toward zero and stays there no matter what you do.

Partial flow is a freeze signature too. A trickle at one fixture and nothing at another, or water in the kitchen but not in the upstairs bath, means ice is narrowing one branch. A failing pump loses pressure everywhere at once.

Listen at the breaker. Flip it on for a few seconds and listen at the pressure switch. A submersible is silent from up top, but the switch contacts snap and the gauge should move. If the gauge climbs and holds while the taps stay dry, stop and go looking for ice.

Why running the pump into ice does the damage

A pump has no idea there's ice ahead of it. It sees low pressure at the switch, so it starts, and it keeps pushing against a plug it can't move. Pressure climbs past cut-out until something yields: a compression fitting, a solder joint, the tank tee, a plastic elbow, or the pump's own thrust bearing.

There's a second injury on top of that. A submersible cools itself with water moving past the motor. Dead headed against a frozen line, nothing moves, and the motor heats in still water. Leave it energized long enough and you've turned a fifty dollar fitting into a pump replacement, which is precisely the outcome the homeowner was trying to avoid.

That's why the first step is the breaker and not the thermostat. Kill the power, then start warming things up. Nothing about the thaw goes faster with the pump running, and everything about it goes worse.

Thawing it without splitting the pipe, and what never to do

Work from the faucet back toward the well, and open the nearest tap first. Warming the far end first traps meltwater between two ice plugs, and trapped water with nowhere to expand is exactly what bursts pipe. Give the thawed section somewhere to drain as it goes.

Warm the whole space rather than one spot on the line. A space heater in a closed crawl space, with the hatch shut and the vents temporarily blocked, does more in an hour than a heat gun does in three, and it won't scorch a poly line or melt insulation off a wire. On a metal fitting, a hair dryer held moving is fine. Patience is the technique.

Stay with it. Every winter somebody leaves a heater running unattended in a crawl space overnight, and every winter that goes badly for somebody. Check on it, and pull it when the water comes back.

A short list of things that turn a bad morning into a worse one.

• No torch, ever. Open flame on poly or PVC melts it, on copper it boils water into steam behind the ice and blows the joint, and in a crawl space full of dry framing it starts fires. This is the number one way a frozen line becomes a house fire.
• No boiling water down the well casing. It refreezes, and it washes whatever's on the ground around the casing straight into your drinking water.
• No electric thawing across the pipe. Running current through a line with a welder or a battery charger has burned down houses. It's not a homeowner technique and it's not a good contractor technique either.
• No unvented propane heater in a closed crawl space. You're sealing the space to hold heat, which is also how you concentrate carbon monoxide.
• Don't keep resetting the breaker. Every reset is another push against the plug and more heat in a motor that isn't being cooled.

Keeping it from happening again

Most repeat freezes come down to one weak spot, and once you know where it is the fix is small. Pipe insulation and self regulating heat tape on the exposed run. A foundation vent closed off for the season and a crawl space hatch that actually latches. A pump house with a working heat source and a door that shuts. A frost proof yard hydrant in place of an ordinary spigot.

If the pressure tank sits somewhere that gets truly cold, moving it into conditioned space is worth pricing. It's a day of work that ends a problem you'd otherwise fight every January, and the same trip is a sensible time to deal with a tank that's near the end anyway, since the crew is already there.

In the fall: disconnect every garden hose, shut and drain the outside spigots, and check that the well cap is tight with its vent screen intact. If the house is going to sit empty over the winter, have the system properly drained rather than leaving the heat at 50 and hoping. A drained system can't freeze. A heated one can, the first time the furnace quits while nobody's home.

We walk through this on service calls in the fall, and it's a short conversation. If yours froze once already, that's the address that freezes again. Call 973-853-1550 and we'll find the weak spot before the next cold snap does.