Pipe & Drain

How to Winterize an Unoccupied NYC Home

November 15, 2024·5 min read

A vacant property faces the same freeze risk as an occupied one, with the crucial difference that nobody is there to notice. An occupied home catches a problem when a tap runs oddly. A vacant one catches it when water has been running through a ceiling for a week.

This applies to more situations than people assume: a home between tenants, a property under renovation, an estate awaiting sale, a floor of a two-family that is not currently rented, or a second home. The approach differs depending on how long it will sit and whether heat will run.

Decide which approach you are taking

There are two defensible strategies, and the worst outcome comes from doing neither properly.

Keep the heat on, water on, and monitor. Appropriate for shorter absences and where someone can check in. Simple, and it keeps the building's systems in normal operation.

Or shut the water off and drain the system. Appropriate for longer vacancies, and the only approach that genuinely eliminates the risk — a system with no water in it cannot burst. More work upfront and more work to recommission.

The failure mode is the middle ground: heat turned off to save money while the plumbing stays full of water. That is the single most reliable way to produce a burst-pipe call, and we run them every winter in unheated empty units.

If you are leaving the heat on

Set the thermostat no lower than 55°F — low enough to save meaningfully, high enough to protect the plumbing
Shut off the main water valve if nobody will be there for an extended period, which limits how much water can escape if something does fail
Drain and disconnect outdoor hose bibs, and remove any attached hose
Open cabinet doors under sinks on exterior walls so heated room air reaches the pipes behind them
Leave interior doors open so heat circulates rather than pooling in one part of the building
Make sure the heating system itself has been serviced — a boiler that fails in an empty house takes the plumbing with it
Arrange for someone to check the property during cold snaps, and make sure they know where the main shutoff is

If you are shutting the water off

Close the main, then open every fixture — all taps hot and cold, tub, shower, and any outside bib — working from the highest floor down so the system drains by gravity. Flush every toilet to empty the tanks. Drain the water heater. Drain or blow out any low points in the piping that will not clear on their own.

Traps are the part people forget. Every sink, tub, shower, floor drain, and toilet bowl holds standing water in its trap, and that water can freeze and crack the fitting. It also evaporates over a long vacancy, which lets sewer gas into the building. Pouring plumbing antifreeze into each trap addresses both — use the propylene-glycol type intended for plumbing, not automotive antifreeze.

If the building has a steam or hot-water heating system that will be shut down as well, that is a different exercise and worth getting advice on rather than improvising, since draining a heating system incorrectly creates its own problems.

Things that apply either way

Know where the main shutoff is and confirm it actually turns before you rely on it
Leave the property's heat and water details with whoever is checking on it
Tell your insurer the property will be vacant — many policies treat vacancy differently, and an undisclosed vacancy can affect a claim
Consider a low-temperature alarm or a leak sensor that alerts a phone; these are inexpensive relative to what they prevent
Seal drafts at cellar vents, hatches, and service penetrations, since an empty house has no incidental heat to compensate

Before anyone moves back in

Turn the water on slowly, at the main, with someone present. Opening it fully and walking away is how a small crack becomes a flood. Walk the building with the water on and check under sinks, at the water heater, at visible joints in the cellar, and at ceilings below bathrooms.

If the property sat unheated through a serious cold snap, have the plumbing checked before reoccupying rather than finding out by turning the water on. A pipe that froze and split does not leak while it is frozen — it leaks when it thaws, or when pressure comes back.

Frequently Asked Questions

No lower than 55°F. That is low enough to save meaningfully against occupied-home heating and high enough to protect the plumbing. Turning heat off entirely while leaving water in the pipes is the most common cause of burst-pipe calls in vacant units.

For short absences with someone checking in, heat on and water off at the main is usually sufficient. For longer vacancies, draining the system properly is the only approach that eliminates the risk — a system with no water in it cannot burst.

Yes, if you are draining the system. Traps hold standing water that can freeze and crack the fitting, and over a long vacancy it evaporates and lets sewer gas in. Plumbing-grade antifreeze in each trap handles both — not automotive antifreeze.

It reduces how much water can escape, but water already in the pipes stays there and can still freeze and split them. For an extended vacancy in winter, closing the main and draining the system is the meaningful step.

Yes. Many policies treat vacant properties differently, and an undisclosed vacancy can affect a claim at exactly the moment you need it to be straightforward.

Have the plumbing checked before turning the water back on, and when you do, open the main slowly with someone present. A frozen split does not leak while frozen — it leaks on thawing or when pressure returns.