The Short Version
The well does not freeze. The wellhead almost never freezes. What freezes is plumbing inside an unheated building. That is the whole page, and the reason it is worth a page is that the effort tends to go to the wrong end of the system entirely.
Every autumn we get asked how to protect a wellhead, and the honest answer for most Lakes Region properties is: you do not need to. Meanwhile the pressure tank sitting in an unheated pump house, or the system in a camp that somebody opened a few valves on in October, gets no attention at all. Those are the ones that cost money.
So the useful order of work is to confirm the wellhead is built the way the state requires, then spend your October on the building.
The Pitless Adapter Has Already Solved This
A correctly built modern wellhead is frost-proof by design, and it needs nothing from you in October. The component responsible is the pitless adapter, and it is worth understanding because it explains why so much winter well advice is misdirected.
The pressurised line that carries water from the well to the house does not leave the casing at the top. It leaves through a fitting set into the side of the casing below the frost zone — typically four feet down or more, with NHDES putting the buried line at four to five feet. Everything carrying water is therefore under frost depth. What stands above ground is steel casing with a cap on it, containing air and a static water column far below. There is nothing up there to freeze.
And the casing is supposed to stand proud. New Hampshire rule We 602.02(e)(1) requires a private well casing to extend at least 8 inches above the ground surface, a requirement in force since 1985, with more than 8 inches warranted where seasonal high water can reach the top. That height is not an oversight the cold will exploit. It is deliberate flood protection, and it is doing a job all year.
Which means the single most common piece of autumn wellhead advice is wrong. Piling insulation, hay bales or a tarp over an exposed wellhead addresses a failure mode that is not there, and it holds moisture against the cap and the seal instead. Leave it alone. If you want to do something useful at the wellhead, mark it with a stake tall enough to find after a ploughing, so nobody drives over it and nobody has to dig for it in February.
Every figure in this section is on our NH well costs and construction reference, with the NHDES sources behind it.
A Buried Wellhead Is a Contamination Problem, Not a Frost Solution
Burying a wellhead or sinking it into a pit to keep it out of the cold is the one autumn decision here that does real, lasting harm. It is also common on older Lakes Region property, for a reason that is nobody's fault.
Before pitless adapters came into use in the late 1960s, the top of the casing was finished below the frost zone — in a pit, or simply buried — with the discharge line coming out through a sealing cap. And wells constructed before 2 July 1985 were not required to meet the 8-inch rule, so plenty of camps and older houses around the lakes still have one.
NHDES is unambiguous about what that costs you. A buried wellhead is the most common reason bedrock water wells become bacterially contaminated: a seasonal high water table puts water above the wellhead, surface water enters the well unfiltered, and surface water typically carries total, faecal and E. coli bacteria. Pits are also, in the state's own words, susceptible to rodent infestation as they age and deteriorate.
If you have one, there is a specific thing to look at before the ground hardens:
- Look for staining on the inside walls of the pit, on the surrounding soil, and on the top of the well seal
- Staining above the top of the casing means flood water has been over the wellhead — the casing wants extending, and the water wants testing
- Staining clearly below the top of the casing, or none, means it has not flooded yet — check it again during spring snowmelt and after heavy rain
- Note whether the pit drains anywhere, is vented, and whether the cap is intact
The rules do allow a wellhead below grade in one circumstance only: where raising the casing would create a genuine safety hazard, such as a wellhead in a driveway or parking area. Then the pit must drain to daylight, be vented, and carry a compliant cap just below the top of the pit cover. A pit that holds water is not that.
One detail worth knowing if anyone proposes extending a casing for you: a no-hub rubber coupling with stainless clamps is not permitted for the job, because frost and soil movement pull those apart over time and the well becomes contaminated. Steel to steel, or solvent-welded schedule 40 PVC to PVC. Testing after any wellhead work is sensible regardless — accredited labs are listed here, and bacteria is the cheapest panel there is.
What Actually Freezes
Nearly every genuine freeze call is plumbing in an unheated space, not anything the driller installed. Roughly in order:
1. The pressure tank, switch and gauge
In an unheated pump house, outbuilding, breezeway or crawl space. This is the big one. The tank holds standing water, the switch and gauge sit on small-bore pipework that freezes first, and the whole assembly is often in the coldest corner of the property. A pressure switch is $150–$400 and a pressure tank $400–$1,200, and a freeze usually takes several components rather than one.
2. Above-ground pipe runs
Anywhere the line comes out of the ground and travels through air to reach a building — under a camp on piers, through an open crawl space, along the inside of an uninsulated sill. The buried portion is fine; the three feet of it you can see are not.
3. A surface jet pump
Jet pumps sit in the building rather than down the well, and freezing damages them in a way it cannot damage a submersible. They also lose prime, and a jet pump that has frozen and been restarted dry has usually suffered twice. If your pump is in the basement rather than in the well, it is in the exposed category.
4. Hose bibs and their supply lines
Disconnect the hoses. A hose left attached holds water against the valve and defeats a frost-proof sillcock entirely, which then splits inside the wall and is not discovered until spring.
5. A shallow line under a cleared drive
Undisturbed snow is insulation, and ground that is ploughed or packed bare loses it. A line that has been fine for twenty years under a lawn can freeze where it crosses a drive that is now kept clear all winter. Rare, but it is the one buried failure that does happen.
Almost never: the well itself
The water column is far below frost depth, the submersible pump is deeper still, and the buried line is under four feet of ground. If you have no water in January, the well is the last place to look, not the first.
Component costs are on the data page, and what shortens component life generally is covered in pump lifespan and replacement.
Heated, or Properly Drained. Not In Between
There are two ways to leave a camp for the winter, and the damage happens almost entirely to systems that are halfway between them. Pick one and commit.
The failure we see in April is not a camp somebody forgot about. It is a camp somebody drained hopefully — a few valves opened on a cold October afternoon, the taps left up, and an assumption that the water went somewhere. Water sits in a sagging run, in the bottom third of a pressure tank that was never drained from its own port, in a water heater nobody touched, in a trap.
Option A — keep it above freezing
Reasonable if the building is used in winter or has a reliable heat source.
- Heat set no lower than about 45°F, not the minimum the thermostat offers
- A low-temperature alarm that notifies somebody, because the power cut and the cold snap are the same storm
- Interior doors open and cabinet doors under sinks open, so warm air reaches pipework on outside walls
- Somebody local with a key who will actually go and look
Option B — drain it genuinely empty
The right answer for an unheated camp, and it is a methodical job rather than a quick one.
- Pump off at the breaker first, and left off
- Pressure relieved and the system opened at the lowest point in the building
- Pressure tank drained from its own drain port — opening taps does not empty it
- Water heater drained, and its power or gas off
- Every low point, trap and sagging run opened or blown through
- Non-toxic plumbing antifreeze in traps and toilets, not in the supply pipework
- Washing machine and dishwasher lines dealt with, and any water softener or filter housing drained per its own instructions
The well and the buried line need nothing either way. Winterising a camp is a plumbing exercise that happens to have a well attached.
Two things worth doing while you are there regardless: note the pressure gauge reading at shutdown, and mark the wellhead with a stake you can find in three feet of snow. Both cost nothing and both save a visit later.
No Water in a Cold Snap
Check the breaker for the well pump before you assume anything has frozen. A tripped breaker is the most common cause of no water in any month, and ruling it out is free. If that was it, you are done — that is not a callout.
If the breaker is fine, the pattern tells you most of the rest:
- Some fixtures work and others do not — the well, pump and tank are all working. You have a frozen line inside the building, usually on an outside wall. That is a plumbing job, not a well contractor's, and we would rather say so than drive out.
- Nothing works, pump silent, breaker on — more likely the pressure switch or the wiring than ice. Note the gauge reading.
- Pump runs, no water arrives — switch it off at the breaker now. Running a pump dry destroys it, sometimes within minutes, and a blocked or frozen discharge line gives it nothing to move. Turn it off, then work out why.
- Pressure builds and collapses rapidly — short-cycling, which is a pressure tank question rather than a cold one, though a part-frozen tank can mimic it.
Thaw gently if you find ice: warm air, a heat gun on low at a distance, or simply heating the space. Never an open flame against pipework, and never on a pipe you cannot see the whole length of. And once it thaws, go and look for a split — a line that froze and burst does not reveal itself until it is flowing again, which may be some hours after you got the water back.
The no-water troubleshooter walks this sequence properly, including the branches where the answer is that you do not need us. More on the symptom itself is on no water from the well, and if it does turn out to be the pump or the switch, that is pump repair.
Questions
Is there any point insulating the wellhead?
On a modern well with a pitless adapter, no. The water line is below frost depth and the casing above ground holds air. Covering it traps moisture against the cap and the seal, which is a slow problem rather than a help. The exception is a visibly non-standard installation — an above-ground run of pipe leaving the casing, or a wellhead inside a small enclosure with pipework in it — and in that case what you are insulating is the pipework, not the well.
My wellhead is in a pit with a lid. Does it need doing something about before winter?
Not because of winter, and yes on its own account. The pit is not a frost risk; it is a contamination risk, and that is true in July as much as January. Use this autumn to check it for staining while you can still see the ground, get a bacteria test done, and plan a casing extension for a workable month rather than rushing one now. If the pit is in a driveway or somewhere raising the casing would genuinely be hazardous, it can stay below grade, but it has to drain to daylight, be vented and have a sound cap.
Should I run a tap slowly overnight in a cold snap?
It is a reasonable short-term measure for an interior line you know is marginal, and it is a poor long-term plan on a well. Unlike a municipal supply, every gallon you run is pump cycles and electricity, and on a low-yield well it is drawdown as well. Fix the cause instead: insulate the run, get warm air to it, or reroute it. If you are dripping a tap in a camp you are not living in, you have chosen the worst of both strategies — drain it properly instead.
Does a frozen pipe mean the pump is damaged?
Not by itself. The damage happens when the pump keeps running against ice. A submersible is cooled and lubricated by the water moving past it, so a pump pushing into a blocked line is heating up with nowhere to send what it is moving. That is why the instruction is to switch it off at the breaker the moment you find a pump running with no water arriving. A pump that was switched off promptly usually comes through a freeze fine. A jet pump in the building is a different case, because the freezing itself can damage the pump body.
Is October too late to get wellhead work done?
No, and it is close to the last comfortable window. Extending a casing, correcting a pit, or re-laying a shallow line are all excavation, and excavating frozen ground is slow and expensive — which is one of the reasons NHDES lists all-weather pump access as a benefit of a pitless adapter in the first place. Work booked now goes in on workable ground. Work discovered in January goes in at a disadvantage, if it goes in at all.
We are buying a camp this autumn. What should we check before the first winter?
Whether the wellhead stands at least 8 inches above grade or sits in a pit, where the pressure tank lives and whether that space is heated, whether the pump is a submersible or a surface jet pump, and whether anyone can tell you how the building was winterised before. Those four answers determine your whole winter risk. The wider list is in buying a house with a well.