This is a planning checklist, not a quote or a policy interpretation. Get written pricing from your own vendors, and read your own insurance policy before the season.
Every November, somebody at a Chatham coffee counter says the same thing: "We just turned the thermostat down and locked up." Two months later they're on a conference call with a water-damage restoration crew, a plumber, and an insurance adjuster. The single most expensive misconception on the Outer Cape is that winterizing a seasonal house is a one-afternoon job. It isn't. It's a sequence, and the sequence matters more than any individual step.
This is the checklist we'd hand any absentee owner who wants to keep their house from becoming an insurance claim. Print it. Tape it inside a kitchen cabinet. Work it top to bottom on closing day.
Don't Race the First Hard Freeze
The ocean keeps the Cape milder than inland Massachusetts in late fall, but the first hard freeze still arrives every year, and the cold snaps that burst pipes usually come later in the winter, when a multi-day stretch of frigid weather finds an uninsulated crawl-space line or an exterior hose bib someone forgot.
Plan to close in the fall while it's still comfortable to work outside, not in the cold of late November. Closing a wet house in freezing weather is how people forget the icemaker line.
The Two Mistakes Behind Most Winter Claims
The pattern is boringly consistent:
- Heat left on, water left on, owner gone. The boiler fails or the oil runs out in January, nobody knows for days, and the second floor rains into the first. This is the catastrophic version.
- Water drained, but not all of it. Outdoor shower line, basement utility sink trap, the dishwasher supply, the fridge icemaker, the in-line filter under the kitchen sink. One forgotten low point freezes, cracks, and floods on the spring re-opening.
The checklist below is designed around preventing both.
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Claim a spotHeat-On or Drained: Pick One and Do It Fully
The Massachusetts Division of Insurance publishes specific winter freeze-up guidance (mass.gov/info-details/understanding-home-insurance), and it splits houses into two cases:
- House unoccupied at times during winter, with hot water heat: set the thermostat no lower than 60 degrees and install a low-heat alarm; have a plumber install a low-water cutoff on a forced hot water boiler; if heated by oil, install a low-oil alarm; and have the house checked once a week (mass.gov DOI).
- House not occupied at all during the winter: have the water service shut off in the street; drain all domestic water lines and heating lines and leave the drain valves open; drain plumbing fixtures, boilers and water heaters; shut off gas service at the meter; and have the house checked weekly (mass.gov DOI).
Half-measures are where the trouble lives. A thermostat turned down to save oil, with water still in the lines, is neither case.
Whichever route you choose, don't trust the hallway thermostat alone. Put an inexpensive wireless freeze sensor on the floor of the coldest room (often the one over a crawl space) and set it to alert your phone well before temperatures get near freezing. Ask your agent whether your policy requires any monitoring on a seasonal home.
Plumbing: The Drain-Down Sequence
This is the order. Doing it out of order is how you trap water somewhere it'll later freeze.
- Shut the main at the street (curb) stop or the meter. The DOI guidance for a house unoccupied all winter is to have the water service shut off in the street (mass.gov DOI). Call your town water department or water district to ask how to schedule a curb shut-off and whether there's a fee; procedures vary by town.
- Open every fixture from the highest floor down. Hot and cold. Including the outdoor shower, hose bibs, and the basement utility sink.
- Drain the water heater through its bottom valve into a hose run to a floor drain. Tankless units have a specific isolation-valve flush procedure in their manual. Follow it.
- Blow out the lines with a compressor if you have any exterior or crawl-space plumbing. Use low pressure and follow your plumber's guidance; too much pressure can damage fittings. Most owners skip this step, and many pay for it the following spring.
- Pour RV antifreeze (the pink stuff, propylene glycol, not automotive) into every P-trap: kitchen sink, every bathroom sink, tub, shower, washing machine standpipe, basement floor drain, and the toilet bowl after you've sponged it dry. Follow the product label for amounts.
- Disconnect the icemaker line and the dishwasher supply at the valve. Both are notorious.
- Label the main shut-off with a tag reading the date you closed and your phone number. A caretaker or plumber arriving in February shouldn't have to guess.
Hiring a Caretaker
Most absentee owners eventually hire a property checker. The DOI guidance calls for a weekly check whether the house is heated or fully drained (mass.gov DOI), so price out a weekly visit as your baseline.
When you get quotes, ask each caretaker for:
- Per-visit pricing for weekly and storm-response visits
- What a visit includes (interior walk-through, temperature and leak check, briefly running faucets on a heated house)
- Closing-day winterization and spring re-opening pricing, if they offer it
- A written or app-based visit log you can hand an adjuster
Prices vary by town, drive time, and what's included, so get at least two written quotes. If you install smart leak and temperature sensors, ask your insurance agent whether your carrier offers any credit for them.
Insurance: The Clauses Nobody Reads Until It's Too Late
Go find your policy. Many homeowners policies limit coverage when a home sits empty, and the exact language controls. Search for these phrases:
- "Vacant." On the widely used ISO Homeowners 3 Special Form (HO 00 03 05 11), coverage for vandalism and malicious mischief, and for glass breakage, does not apply if the dwelling has been vacant for more than 60 consecutive days immediately before the loss (ISO HO 00 03 05 11, filed copy at maine.gov). Your carrier's form and Massachusetts endorsements may differ, so read your own.
- "Freezing." The same HO-3 form excludes damage from freezing of plumbing, heating, or sprinkler systems and appliances unless you used reasonable care to either maintain heat in the building or shut off the water supply and drain all systems and appliances of water (ISO HO 00 03 05 11).
- "Unoccupied" and any inspection or notice requirements. Some carriers add their own conditions for seasonal homes. Ask your agent directly.
Call your agent in October, not December. Ask in writing whether your policy has vacancy or unoccupancy conditions that apply to your closing dates, and whether a vacancy endorsement is available and what it costs.
Wildlife, Security, and Bridge Timing
A few items that aren't really plumbing but cost owners every year:
- Mice get in through utility penetrations, the dryer vent, and the bulkhead seal. Steel wool plus expanding foam at every utility penetration. Replace dryer-vent louver flaps that don't close fully.
- Cut a deal with a neighbor to pick up storm debris between caretaker visits. A branch left on the roof all winter can become a leak by April.
- Leave one interior light on a timer, and consider disconnecting the garage door opener if you won't be using it, so a power glitch or stray remote can't open the door while you're gone.
- Bridge timing. Westbound traffic over the Sagamore and Bourne bridges is typically heaviest on weekend afternoons, especially Sundays. Leaving early in the day, or in the evening, usually beats it.
The Print-and-Go Checklist
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Tape this inside a cabinet. Initial each line.
Don't-Miss Warnings
Don't trust a single thermostat reading. A hallway thermostat can read comfortably while the crawl space under a bathroom is far colder. Put a wireless sensor in the worst room and check it from your phone. If you take only one piece of advice from this guide, take that one.
Don't skip the spring re-opening check. When you turn the main back on in spring, do it slowly with a single upstairs fixture open, and walk the entire house listening and looking before you leave. A pinhole crack in a basement line can leak a lot of water before anyone notices. A few minutes of attention on re-opening day is the cheapest insurance on the Cape.
Don't Leave Without
Cape Cod Certified picks — essentials worth packing for this trip:
- Hand-Painted Cape Cod Lobster Traps Blown-Glass Ornament — $24: ~3-inch blown-glass ornament reverse-hand-painted with a Cape Cod lobster-trap coastal scene; gift boxed.
- Govee WiFi Thermometer w/ Freeze Alerts — $30: Get a phone alert the moment your Cape house drops toward freezing — the warning that saves burst pipes.
- DampRid Hi-Capacity Moisture Absorber Bucket — $12: Set a few around a shuttered Cape house to pull damp salt air from closed rooms — no power, lasts ~6 months.
Where to Take This Next
- The Cape Cod Certified directory — every business visited in person →
- Bookable Cape Cod experiences →
Figures in this guide were checked against official sources on October 1, 2026. Costs, rates and policy terms change; confirm before you act.
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Frequently asked questions
What temperature should I keep my Cape house at if it's going to be empty most of the winter?
The Massachusetts Division of Insurance recommends a minimum thermostat setting and a low-heat alarm for houses unoccupied at times but still heated; check mass.gov for the current threshold. The safer alternative is to shut the water off at the street and drain every line — keeping heat turned low without draining is how most burst-pipe claims start.
What kind of antifreeze do I put in the drains when I winterize a house?
Use RV antifreeze — the pink propylene glycol formula, not automotive antifreeze — poured into every P-trap: kitchen sink, all bathroom sinks, tubs, showers, the washing machine standpipe, floor drains, and the toilet bowl after sponging it dry. Check the product label for how much to use in each fixture.
Will my homeowners insurance cover damage from frozen pipes if the house was vacant all winter?
Many policies exclude freezing damage unless you either maintained heat or shut off and drained the water system entirely — half-measures satisfy neither condition. The widely used HO-3 form also limits coverage for vandalism and glass breakage after a home has been vacant for an extended consecutive period. Read your own policy and call your agent before closing up, not after a loss.
How do I keep mice out of my beach house when it's shut up for the season?
Mice typically enter through utility penetrations, the dryer vent, and the bulkhead seal. Pack steel wool into every utility penetration and seal it with expanding foam, then replace any dryer-vent louver flaps that no longer close fully — the guide flags those three entry points as the recurring culprits.
Do I need to hire someone to check on my house while it's closed for the winter?
Massachusetts Division of Insurance guidance calls for a weekly check whether the house is being heated or has been fully drained. When getting caretaker quotes, ask what each visit includes and request a written or app-based visit log you could hand an insurer; get at least two written quotes, since pricing and scope vary by town and drive time.
