Do you head off-Cape for the winter and worry about your South Dennis place while storms roll through? You are not alone. Cape Cod winters bring freeze–thaw cycles, nor’easters, heavy wet snow, and the occasional power outage. A simple plan can keep your second home safe, cut utility costs, and give you peace of mind. In this guide, you’ll get a clear checklist tailored to Dennis and Barnstable County conditions so you can shut down confidently or keep heat on safely. Let’s dive in.

Why winterizing matters on Cape Cod

Cape Cod’s maritime climate is milder than inland Massachusetts, but sustained cold snaps still happen. That mix, plus strong coastal storms, raises the risk of frozen pipes, ice dams, and power outages. Freezing conditions typically begin in late fall and can linger into early spring. The best time to winterize is before the first sustained freeze, and you should maintain protections through March in most years.

A good plan focuses on four things: preventing pipe freezes, protecting mechanical systems, minimizing energy use, and enabling remote monitoring so you can act fast if something goes wrong.

Choose your strategy: drain or heat on

Your biggest decision is whether to shut off and drain the water system or leave heat on with the plumbing pressurized. Both can work. Choose based on how often you visit, your ability to monitor power and temperature, and whether your home has systems that must remain active, like fire sprinklers.

Option 1: Shut off and drain (best if you cannot monitor)

If you will be away for long stretches and cannot ensure reliable heat or power, draining is the safest path.

• Shut off the main water supply. Label the valve so a local contact can find it quickly.
• Open all faucets to drain hot and cold lines. Do not forget exterior spigots and showers.
• Flush toilets to empty tanks. Add a small amount of non-toxic RV or plumbing antifreeze to toilet bowls and sink, tub, and shower traps if recommended by your plumber.
• Drain or bypass the water heater. Follow the manufacturer’s process. If the system is drained and you have gas, confirm the correct setting for the pilot.
• Winterize appliances connected to water. Check the manual for dishwashers, washing machines, and ice makers.
• Protect well equipment if you have a private well. Shut off power to the pump and drain the pump and pressure tank per your well contractor’s guidance.
• Document the location of valves and shutoffs. Keep notes and photos for anyone checking the house and for insurance records.

Important: If your home has a fire-suppression sprinkler system, do not drain it without a licensed sprinkler contractor’s guidance. Sprinklers often must remain pressurized and professionally maintained.

Option 2: Leave heat on safely (best if you can monitor)

If you keep heat on, protect pipes and set up alerts so you know about changes right away.

• Set a safe minimum temperature. Many emergency-preparedness and insurance sources recommend 55°F for a vacant home with pressurized plumbing. If you have known cold spots, consider slightly higher.
• Insulate exposed pipes. Focus on crawlspaces, attics, garages, and exterior walls. Heat tape or electric pipe tracing can help with problem runs. Use UL-listed products and follow instructions.
• Add leak detection and an automatic water shutoff. Smart sensors under sinks, by the water heater, and near laundry appliances can catch problems early.
• Open cabinet doors under sinks when you leave. This allows warm air to circulate around pipes at exterior walls.

Smart monitoring and backup power

Thermostats and alerts

A smart thermostat with remote monitoring helps you keep tabs on temperature and equipment status.

• Choose a thermostat that supports remote control, app alerts for temperature drops or loss of connection, and multiple room sensors for cold spots.
• Test the app and alerts before you leave. Confirm the thermostat and any sensors show accurate readings.
• Add battery backups for your modem, router, and hub. A small uninterruptible power supply can keep your connection alive during short outages so you still get alerts.
• Consider a monitored HVAC service. If a fault occurs, a technician or local contact can be notified quickly.

Power, Wi‑Fi, sump pumps, and generators

Winter storms can knock out power and internet, which disables heat, sump pumps, and alarms.

• Sump pump prep. Test the pump and discharge line. Install a battery backup or a water-powered backup if appropriate. Tie any pump alarms to a phone or smart device.
• Generators. A portable or standby generator can keep heat and critical systems running during extended outages. Use proper fuel storage and carbon-monoxide safety. Have a licensed electrician install a transfer switch for standby units.
• Utility coordination. Know how to report outages to your electric utility and how you will get updates. Save account numbers and contacts in your phone and share them with your local keyholder.

Generators help during outages, but you still need pipe insulation and a safe thermostat setting to reduce freeze risk.

Septic, roof, and exterior prep

Many Dennis homes rely on septic. Roofs, gutters, and site drainage also need attention before winter.

• Septic system care. If your system is due for service, schedule an inspection and pump before a long vacancy. Protect exposed components like pumps or control panels with appropriate insulation or covers. Avoid driving over the leach field and maintain snow cover for insulation if your septic professional recommends it.
• Gutters and downspouts. Clean them to reduce ice dam risk. Make sure downspouts discharge away from the foundation.
• Attic insulation and ventilation. A well-ventilated, properly insulated attic helps keep the roof cold and reduces ice dam formation.
• Trees and limbs. Trim dead or dangerous branches that could fall during winds or heavy snow.
• Doors, windows, and weatherstripping. Seal drafts to help maintain stable interior temperatures and reduce energy use.

Security, mail, and on-site checks

Visible vacancy invites problems. Plan for simple signals and local oversight.

• Mail and deliveries. Place a USPS Hold Mail request or have a neighbor collect packages. Avoid visible buildup at the door.
• Security system. Use a monitored system with cellular backup if possible. Make sure the alarm company has current contact information and a local keyholder.
• Local contact and check-ins. Arrange periodic walk-throughs from a trusted neighbor, property manager, or contractor. Provide written authorization and emergency contacts so they can act if there is an alert or storm damage.

Insurance and local rules

Before you leave, call your insurer about vacancy clauses and winterization requirements.

• Coverage expectations. Some policies require you to maintain heat, perform periodic inspections, or fully winterize to keep freeze damage covered. Ask about required minimum temperatures, check-in frequency, and documentation.
• Proof of winterization. Keep receipts, photos, and service records. Insurers often request evidence after a claim.
• Licensed contractors and permits. Use licensed plumbers, electricians, HVAC technicians, and septic professionals. Town permits are often required for standby generators and major electrical work. Check with the Town of Dennis for local requirements.

Your timeline checklist

Use this step-by-step plan to stay organized.

2–4 weeks before departure

• Decide your strategy: drain the system or leave heat on. Consult a licensed plumber or HVAC technician for complex systems like sprinklers or radiant heat with glycol.
• Schedule HVAC service. Have combustion appliances checked, fuel delivery arranged if you heat with oil, and thermostats verified.
• Service septic if due. An inspection and pump can prevent winter issues, especially for systems with pumps or controls.
• Clean gutters and trim risky limbs. Reduce ice dam and storm damage risk.
• Set up smart monitoring. Install or verify a smart thermostat, water-leak sensors, and any camera or alarm systems. Confirm you can access them remotely.
• Prepare for power issues. Add battery backups for your modem and router, test sump pump backups, and service your generator if you have one.
• Notify your insurer. Confirm requirements for vacant periods and how to document compliance.
• Arrange local support. Set up a USPS Hold Mail or a pickup plan, and choose a local keyholder for inspections and emergencies.
• Document the property. Take photos and note valve and shutoff locations. Share key information with your local contact.

Day you leave

If draining the system:

• Shut off the main water supply. Open all faucets and exterior spigots to drain the lines.
• Flush toilets and add a small amount of non-toxic antifreeze to bowls and traps as advised by your plumber.
• Drain or bypass the water heater per manufacturer instructions. Turn off or set appliances connected to water to winter mode.
• Shut off power to well equipment and drain the pump and pressure tank if applicable.

If leaving heat on:

• Set thermostats to a safe minimum, commonly 55°F. Verify remote access and test alerts.
• Open cabinet doors under sinks on exterior walls to circulate warm air.
• Confirm pipes in cold areas are insulated. Double-check that leak sensors are active and connected.

For both approaches:

• Secure windows and doors. Arm your security system and confirm the alarm company has your keyholder’s information.
• Review your emergency plan with your local contact.

While you’re away

• Check in remotely weekly or monthly. Confirm Wi‑Fi and thermostat connectivity, review temperature logs, and scan alerts from leak sensors and security cameras.
• After storms, request a quick exterior and interior check. Ask for photos if anything looks off.
• Keep fuel deliveries or generator maintenance current if applicable.

When you return

If you drained the system:

• Repressurize carefully. Open the main slowly, check for leaks, and purge air from lines. Refill and restart the water heater per the manufacturer or with a plumber’s help.

If you left heat on:

• Walk the home. Look for any signs of leaks, condensation, or mold. Test fixtures and appliances. Verify sump pump operation and clear any gutter or downspout blockages.

Local notes for South Dennis owners

• Weather pattern: Expect occasional sustained freezes, heavy wet snow, strong winds, and coastal storm impacts from late fall through early spring.
• Storm readiness: Power and internet interruptions can happen during nor’easters, so plan for monitoring backups and generators.
• Septic prevalence: Many Dennis homes use septic. Ask your local septic professional about winter best practices for your system.
• Town coordination: For generators, electrical upgrades, or plumbing work that may require permits, contact the Town of Dennis before scheduling.

Taking these steps now protects your investment and saves you from expensive emergencies later. If you would like local contractor referrals or guidance on getting your Cape home market-ready in any season, reach out to The Cape House Team. We know the mid- and lower-Cape villages inside and out and are here to help you protect and enjoy your home year-round.

Ready to winterize with confidence or prep for your next chapter on the Cape? Connect with The Cape House Team and Start Your Cape Cod Story.

FAQs

Should I shut off water or leave heat on in my South Dennis second home?

• If you cannot reliably monitor power and temperature, shut off and drain; if you can monitor and maintain heat with alerts and insulation in place, leaving heat on near 55°F works well.

What thermostat setting helps prevent frozen pipes in a vacant Cape Cod home?

• Many sources recommend a minimum of around 55°F for pressurized plumbing, combined with pipe insulation and leak detection to cover cold spots.

Do I need a generator for my second home on Cape Cod?

• Not always, but if a power outage would risk major damage, a portable or standby generator with a proper transfer switch is a smart backup.

How should I winterize a septic system before leaving for the season?

• If due, have it inspected and pumped, protect exposed components with appropriate insulation, and avoid traffic over the leach field during winter.

What insurance steps should I take before winterizing a vacant home?

• Call your insurer to confirm vacancy requirements, such as minimum heat settings or inspection frequency, and keep receipts and photos as proof of winterization.