Property Winterization Guide: Protecting Pipes, HVAC, and Plumbing Systems

Winterization is the most cost-critical preservation task for vacant properties. A single burst pipe can cause tens of thousands of dollars in damage — flooded floors, destroyed drywall, mold growth, and structural compromise. Proper winterization protects plumbing, HVAC, and water-connected systems from freeze damage during cold months.

When to Winterize

Most investors and servicers require winterization to be completed by November 1 for northern states and December 1 for southern states, though specific dates vary by investor and region. Properties should be winterized whenever they will be vacant and without heat during months where temperatures may drop below freezing — even in southern states, overnight freezes can burst unprotected pipes.

Step-by-Step Winterization Process

1. Shut Off Water Supply

Locate and shut off the main water supply valve. For properties on well water, turn off the well pump at the breaker. Open the lowest faucet in the home to relieve pressure and allow the system to begin draining.

2. Drain All Water Lines

Open all faucets (hot and cold) and flush all toilets. Use an air compressor to blow remaining water from supply lines — start from the highest point in the system and work down. Pay special attention to horizontal runs and low points where water collects. Drain the water heater completely through the drain valve at the bottom of the tank.

3. Treat Drain Traps and Toilets

Pour non-toxic RV antifreeze into all drain traps — every sink, tub, shower, floor drain, and washing machine standpipe. Add antifreeze to all toilet bowls and tanks after flushing. This prevents the trap water from freezing and cracking porcelain or drain fittings.

4. HVAC and Mechanical Systems

If the property will have power, set the thermostat to 55°F as a secondary freeze protection measure. If utilities will be disconnected, ensure all water is removed from boiler systems, hydronic heating loops, and humidifier lines. Disconnect and drain washing machine hoses. Cap or plug dishwasher and ice maker supply lines.

Documentation Requirements

Photo-document every step of the winterization process: the main shutoff valve in closed position, each faucet open, the water heater drain, antifreeze in each trap and toilet, thermostat setting, and any damage or conditions found during the process. Include the property address and date in your documentation. Incomplete winterization documentation is a common chargeback trigger.