An empty house in a Chicago winter is at its most exposed. Nobody runs the faucets, nobody hears the furnace short-cycle, and nobody spots the first drip from a split copper line before it turns into a flooded basement. Whether you are a snowbird heading south for three months, an estate executor holding a parent's bungalow until it sells, or a landlord between tenants in a two-flat, the job is the same: keep water out of the pipes that can freeze, keep heat on the pipes that can't be drained, and set up a way to know quickly if something goes wrong. This guide walks through each step in order, with notes on the Chicago building stock that makes some homes harder to protect than others.

Step 1: Decide Between "Heated and Watched" and "Fully Drained"

Before touching a valve, choose your strategy. There are two realistic approaches, and mixing them halfway is where most vacant-home pipe failures start.

  • Heated and watched: The furnace stays on, the water supply stays live, and someone checks the house regularly. This suits short absences (a few weeks to a couple of months) and homes with hot-water or steam radiators, where draining the heating system is a bigger project.
  • Fully drained (dry winterization): The water supply is shut off and every line, fixture trap and appliance is emptied, often with plumbing antifreeze added to traps. This suits long vacancies, estate properties that may sit through the whole season, and homes where nobody can check in reliably.

A simple rule of thumb: if you cannot guarantee that a person will walk through the house at least once a week, lean toward fully drained. Heat alone protects pipes only as long as the furnace, the igniter, the thermostat batteries and the gas and power service all keep working.

An illustrative example

To make the choice concrete, consider two hypothetical households (names and details are fictional). Ray and Linda Ostrowski, retirees in a Jefferson Park Cape Cod, leave for Arizona from January through March. Their next-door neighbor, Tomás Herrera, a retired school custodian who knows his way around a boiler room, agrees to walk through weekly, so they choose heated-and-watched. Meanwhile, Dana Whitfield, acting as executor of her late father's Portage Park bungalow, lives out of state and expects the house to sit unsold until spring. With no one nearby to check it, she hires Marcus Bell, a licensed plumber from a nearby suburb, to fully drain the system. Same city, same cold, two different right answers.

Step 2: Set the Heat Correctly (Even If You Drain)

If the house stays heated, the thermostat setting matters more than people expect.

  • Keep the thermostat at 55°F or higher. This is the setting most commonly recommended for unoccupied homes. Lower settings save little and leave exterior-wall pipes close to the edge during a polar-vortex cold snap.
  • Open cabinet doors under kitchen and bathroom sinks on exterior walls so room heat reaches the supply lines.
  • Open interior doors so heat circulates to back bedrooms, enclosed porches and the bathrooms that Chicago bungalows often tuck against a cold outside wall.
  • Replace the thermostat batteries and the furnace filter before you leave. A dead thermostat or a choked filter that trips the high-limit switch are classic causes of a silent no-heat event.
  • Schedule a furnace tune-up in the fall so the igniter, flame sensor and draft inducer are checked before the house is left alone.

Even in a fully drained house, keeping some low heat (or at least not shutting gas service off entirely) helps protect the boiler, the water heater tank if it is not drained, and finishes like plaster and hardwood from extreme temperature swings.

Step 3: Find and Protect the Highest-Risk Pipes

Chicago-area homes share a handful of predictable weak spots. Walk the house with a flashlight and note each one.

  • Exterior hose bibbs (sillcocks): Close the interior shutoff that feeds each outside spigot, open the outside spigot to drain it, and disconnect every garden hose. A hose left attached traps water inside the valve body.
  • Crawlspaces and enclosed porches: Many older bungalows and frame houses have supply lines running through unheated rear porches or shallow crawlspaces. Add foam pipe insulation at minimum; consider thermostatically controlled heat cable (UL-listed, installed per the manufacturer's instructions) on lines that cannot be rerouted.
  • Kitchen sinks on exterior walls: Common in Chicago two-flats and greystones, where kitchens sit at the back of the building.
  • The water service entry in the basement: In older homes the main line enters through a foundation wall that may be cold. Water service lines are buried below the frost line (local frost depth is commonly cited at about 42 inches, and Chicago's standard burial depth for water services is deeper still), but the exposed section where the line enters the basement can still freeze if the basement gets cold.
  • Garage and attic lines: Any plumbing in an attached garage or attic space should be drained or insulated.

For a broader look at where pipes freeze first in local housing, see our guide on frozen pipe prevention in Chicago.

Step 4: Shut Off the Water and Drain the Lines

If you chose the fully drained approach, work through the house in this order. If you are heating and watching, still do the first item so you know exactly where the shutoff is.

  1. Locate the main shutoff valve. In most Chicago homes it is in the basement near where the service line enters, often near the water meter. Test that it turns fully. Old gate valves can seize or break; if it won't close, have a licensed plumber replace it before winter.
  2. Know about the curb stop. The service line also has a buffalo box (curb stop) in the parkway or near the property line. In Chicago it is typically operated by the city's Department of Water Management, not the homeowner. For a long estate vacancy, ask the city about shutting service at the curb.
  3. Close the main valve, then open every faucet, hot and cold, starting at the top floor and working down. Leave them open.
  4. Open the lowest drain point (a basement laundry tub faucet or a drain valve near the main) to let the system empty.
  5. Flush every toilet and hold the handle down to empty the tank. Sponge out what remains in the tank.
  6. Turn off and drain the water heater. Shut off gas or power to it first (set gas units to "pilot" or "off" per the label), let the water cool, then drain through the bottom valve with a hose to a floor drain.
  7. Blow out the lines with compressed air if you have the equipment and experience, or have a plumber do it. Gravity draining leaves water in low spots and horizontal runs.
  8. Add plumbing antifreeze to traps. Pour non-toxic RV/plumbing antifreeze (propylene glycol, not automotive antifreeze) into each sink, tub, shower and floor drain trap, and into toilet bowls. This keeps the trap seal intact so sewer gas does not enter the house.
  9. Disconnect appliances: Shut supply valves to the washing machine, dishwasher, ice maker and any water filter, and drain hoses where possible.
  10. Label everything. Tape a note to the main valve and the water heater listing what was drained and what must be refilled first in spring.

Hot-water and steam heating systems are a special case. Draining a boiler loop is a job for a heating contractor, and many owners of older greystones and two-flats choose to keep those systems running rather than drain them. If you do drain a hydronic system, it typically must be refilled with glycol or kept dry until a professional restarts it.

Step 5: Protect the Basement and Sump Pit

A vacant winter house can still flood from outside water, not just from pipes. Chicago's January thaws and early-spring rains arrive before most snowbirds return.

  • Leave the sump pump powered and test it by pouring a bucket of water into the pit before you leave. Clear ice and debris from the discharge line outlet.
  • Consider a battery backup pump if the house will sit for months; see our battery backup sump pump guide.
  • Check floor drains and backwater valves. Many Chicago basements sit on the combined sewer system, and a heavy thaw-plus-rain event can push water back up floor drains. If the home has a backwater valve, confirm the flap opens and closes without sticking.
  • Raise stored items off the basement floor onto shelving, especially boxes of family belongings in an estate property.

Step 6: Set Up Remote Monitoring

The best winterization still benefits from early warning. A burst pipe discovered in hours is an inconvenience; one discovered in three weeks can mean saturated floors, ceilings and mold.

  • Smart thermostat or temperature sensor: Choose one that sends an alert when indoor temperature drops below a set point (for example, 45°F). This tells you the heat has failed before pipes reach freezing.
  • Water leak sensors: Place battery-powered sensors near the water heater, under sinks, beside the washing machine and at the base of the sump pit.
  • Automatic water shutoff valve: A motorized valve on the main line that closes when a sensor detects a leak or a flow anomaly. This is one of the more effective upgrades for a home that is heated but not drained.
  • Power-outage alert: Some sensors and smart plugs report when they lose power, which is useful because an outage also stops the furnace blower and the sump pump.
  • A low-tech backup: A wireless thermometer or a simple "freeze alarm" that dials or texts a phone number works where Wi-Fi is unreliable.

Make sure the home's Wi-Fi and the monitoring service will remain active. Estate properties sometimes have internet service cancelled along with other utilities, which quietly disables every smart device in the house.

Step 7: Arrange In-Person Check-Ins

Sensors don't see everything. Line up a trusted person (a neighbor, a relative or a property-check professional) with a written routine.

  • Frequency: At least weekly; more often during deep cold snaps when overnight lows fall below zero.
  • What to check: Thermostat reading, any water on floors, ceiling stains, the sump pit level, frost or ice on basement walls near the water entry, and that the furnace is running.
  • Give them a key and a sheet listing the main shutoff location, the circuit breaker panel, and the emergency referral line 312-801-1888.
  • Keep the house looking lived-in. Arrange snow removal so walks and the front stoop stay clear; an unshoveled walk signals vacancy.

In the hypothetical example above, Tomás Herrera's checklist for the Ostrowski house fit on one index card taped inside the back door: thermostat at 55, look under both sinks, check the sump pit, glance at the basement ceiling under the bathroom.

Step 8: Restart the House Safely in Spring

Returning water to a drained house carelessly can cause the very damage you prevented.

  1. Close all faucets and drain valves you opened.
  2. Refill the water heater first before restoring its gas or power; firing an empty tank can damage the element or burner.
  3. Open the main valve slowly, a quarter turn at a time, and listen for running water where there shouldn't be any.
  4. Walk every room looking for drips at fittings, under sinks and on basement ceilings. Pipes that split during a freeze often show leaks only when pressure returns.
  5. Run each faucet until the air clears and the antifreeze flushes from traps.
  6. Reopen the interior hose bibb valves only after the last hard freeze has passed.
  7. Relight or re-energize the water heater only once the tank is full and no air sputters from a hot-water faucet; follow the label's lighting instructions for gas units.
  8. Reconnect appliances one at a time (washing machine, dishwasher, ice maker, water filter) and watch each supply hose for a few minutes after opening its valve.
  9. Re-test the sump pump with a bucket of water and check that spring snowmelt has not left the pit near its high-water mark.
  10. Check monitoring gear: replace leak-sensor batteries, confirm the automatic shutoff valve is reset to open, and review the temperature log for any dips you missed.
  11. Look and sniff for slow leaks. A musty smell, bubbling paint or soft drywall near plumbing walls can point to a small leak that dripped for weeks; see our guide on musty basement smell causes.

If you find a split line or a soaked ceiling when you return, our burst pipe shutoff checklist covers the first steps for stopping the water and limiting damage.

Quick Winterization Checklist

  • Choose heated-and-watched or fully drained, and commit to it
  • Thermostat at 55°F or higher, new batteries, new furnace filter
  • Hoses disconnected, interior hose bibb valves closed, spigots drained
  • Main shutoff located and tested; curb stop discussed with the city for long vacancies
  • Lines drained, toilets emptied, water heater drained, traps treated with plumbing antifreeze
  • Sump pump tested, backup considered, discharge line clear
  • Temperature and leak sensors installed; internet service kept active
  • Weekly in-person check-in arranged with a written routine
  • Spring restart plan taped to the main valve