Closing the Water System: Well Pumps, Pressure Tanks and Water Heaters

To winterize a cottage water system, always shut off power to the well pump first, then drain in order: open all taps, empty the pressure tank, drain the pump housing (for jet pumps), shut down and drain the water heater, clear the hot and cold lines, and finish with plumbing antifreeze in every trap and fixture.

The order matters more than any single step. Most of the expensive water-system damage we see at cottages across Grey-Bruce and the Lake Huron shore traces back to steps done out of sequence — or one component quietly forgotten. This post is the deep-dive companion to our complete winterization checklist, zoomed in on the three pieces of equipment that cause the most confusion: the well pump, the pressure tank and the water heater.

Why does the pump power go off before anything drains?

A well pump cools and lubricates itself with the water it moves. Take the water away while the motor is still live and it overheats fast — seals warp, bearings suffer, and a jet pump impeller can be wrecked in minutes.

Here’s the trap: the pressure switch doesn’t know you’re closing the cottage. The moment you open a tap and system pressure drops below the cut-in point, the switch calls the pump to start. If the breaker is still on, the pump runs — into an emptying system, with less and less water to move.

So the very first act of a water-system shutdown is boring and takes ten seconds: flip the pump’s breaker off. Then confirm the pressure switch circuit is dead too. Leaving the pressure switch live is one of the classic errors we cover in our roundup of common cottage-closing mistakes, and it’s the one with the fastest path to a dead pump.

How do you drain the pressure tank?

With the pump powered off, open every tap in the cottage — hot and cold, highest fixture first — and let the system pressure bleed down. Then deal with the tank.

Most cottages have a bladder or diaphragm pressure tank: a steel shell with an air charge on one side of a rubber membrane and your water reserve on the other. Open the tank’s drain valve, or the lowest tap on its line, and let the water side empty completely. You’ll often hear air working through as the bladder pushes the last of the water out.

While the tank is empty, put a tire gauge on the Schrader valve (it looks just like a car tire valve, usually under a plastic cap on top). The air pre-charge should typically sit about 2 psi below the pressure switch’s cut-in setting — commonly 28 psi for a 30/50 switch. If the gauge reads near zero, or water spits out of the valve, the bladder has likely failed and the tank is waterlogged. Fall is the right time to find that out; spring opening day is not.

Jet pump vs submersible: what actually needs draining?

This is where cottage owners most often guess wrong, because the answer depends on which kind of pump the cottage has — and plenty of owners inherited the system and have never been told.

A jet pump sits above ground, usually in a pump house, crawl space or basement, and pulls water up from the well. Everything about it is exposed to freezing air. A submersible pump hangs at the bottom of the well itself, below the frost line, and pushes water up. The pump itself sits below the frost line — but the pipe run between the well and the cottage still matters.

	Jet pump (above ground)	Submersible pump (in the well)
Pump motor and housing	Must be drained — remove the casing drain plugs; the pump body holds water even after lines are empty	Stays in the well below the frost line — no draining needed
Suction / supply line	Drain back to the well or foot valve; shallow-well lines hold water the full run	Supply line from the pitless adapter to the cottage needs clearing where it rises above frost depth
Pitless adapter	Not applicable on most jet systems	The buried connection at the well casing is below frost, but the line from there into the building is the vulnerable stretch
Priming water	Pump must be re-primed in spring — plan for it	Self-priming by design; nothing to re-prime
Foot valve / check valve	Foot valve in the well holds the water column — the line above it needs draining	Check valve(s) above the pump hold pressure in the drop pipe; house-side valves can trap water in line sections

The single most common miss on jet-pump systems: draining the lines but not the pump housing. The casing has one or two small drain plugs for exactly this reason. Water left inside the pump body can crack the housing over winter — a spring surprise nobody enjoys.

On submersible systems, foot valves and check valves deserve a moment’s thought. A check valve does its job by refusing to let water flow backward — which also means it can hold water captive in a pipe section that looks drained from the tap end. Knowing where the valves sit in a given system is half the job, and it’s a big part of why a professional visit starts with tracing the system rather than just opening taps. Our overview of how cottage plumbing gets winterized walks through that whole-system logic.

How do you drain a cottage water heater safely?

The water heater is the biggest single container of water in the cottage — typically 150 to 270 litres — and one of the most commonly forgotten items at closing time. Left full in an unheated building, it’s a burst risk: water expands roughly 9% when it freezes, and a sealed steel tank has nowhere to put that expansion except through its own fittings or walls.

The safe sequence:

1. Cut the energy source first. Electric tank: breaker off. Gas or propane tank: control to “off” and close the gas valve. This step is not optional — electric heating elements burn out quickly when they run exposed to air, and it happens the moment the water level drops past them.
2. Close the cold-water supply to the tank.
3. Connect a garden hose to the drain valve at the bottom and run it to a floor drain or outside to grade below the tank.
4. Open a hot tap at a fixture (or lift the temperature-and-pressure relief valve lever briefly) to let air in — otherwise the tank glugs and drains painfully slowly.
5. Drain completely. Let it run until the hose is empty.

Two worthwhile extras while you’re there. First, let the last of the flow flush sediment out — cottage well water carries minerals that settle in the tank bottom, and draining is the one time each year the sediment gets flushed out as part of the same job. Second, a tank that’s being opened up anyway is a convenient time to eyeball the anode rod situation on an older heater; a consumed anode means the tank is rusting from the inside, and better to learn that in October than mid-July.

What about the hot and cold lines?

Once the tank, pump and heater are empty, the remaining job is the pipe runs themselves. Every horizontal line that sags, every low loop under a floor, every dead-end run to an outdoor tap can hold a pocket of water after “everything’s drained.” Low-point drains handle some of it; compressed air blown through the system handles the rest, which is the approach we take on professional visits because it clears the pockets you can’t see.

Pay attention to the stretch that stays vulnerable no matter what: the supply line where it enters the building, especially through a crawl space or above-grade run. This is where heat tape and pipe insulation earn their keep — as a supporting layer on a line that can’t be fully emptied, never as a substitute for draining. Heat tape only works while the hydro stays on, and anyone who has spent a winter storm season on the Bruce Peninsula or the Huron shore knows rural power does go out. Use CSA-certified self-regulating tape, follow the install instructions, and treat it as backup, not backbone.

If you’re weighing whether to skip all this and just leave the furnace running instead, that’s a real option with real trade-offs — we’ve laid them out in our heat it or drain it decision guide.

Why does plumbing antifreeze go in the traps?

Draining empties the pipes, but every sink trap, shower drain, tub, and toilet still holds water by design — that’s what keeps sewer gas out of the cottage. Non-toxic plumbing antifreeze (propylene glycol, the pink jug — never automotive antifreeze) gets poured into each trap, each toilet bowl and tank, and any floor drains. It displaces the standing trap water while keeping the sewer seal intact.

The mistakes that show up every spring

The same short list accounts for most of the damage we’re called about in April and May:

• Pump housing not drained on jet-pump systems — lines empty, casing full, casing cracked.
• Water heater forgotten entirely — it’s in a closet, out of sight, still holding 200 litres.
• Pressure switch left live — the pump ran itself dry sometime during the draining, or worse, cycled on during the winter.
• Check valves trapping water in line sections that looked empty from the taps.
• Heat tape trusted as the whole plan — then a February outage.

Timing matters too: all of this should happen before the first hard freeze, not after. Our guide on when to close your cottage covers how to read the fall calendar in the Grey-Bruce and Huron-shore snow belt.

What a professional winterization visit covers

Everything above is exactly what we do on a fall visit, in that order: pump power off and confirmed, full system drain including tank and pump housing, water heater shut down and emptied, lines cleared with compressed air, antifreeze in every trap and fixture, and photos of the work so you can see the state we left it in from wherever you spend the winter. On systems we haven’t seen before — from Saugeen Shores up through the South Bruce Peninsula and down the shore to Goderich — we trace the layout first, because every cottage plumber over the decades had their own ideas about where valves belong.

If you’d rather hand the whole sequence to someone who does it all fall, every fall, book your visit through our plumbing winterization page, and see what a full closing and check-in visit includes on our cottage inspections page. Call 519-783-1575 — answered 7 days a week — and we’ll give you a clear quote up front.