How to Winterize Your Plumbing Before a Michigan Freeze

Why Fall Is the Right Time for Plumbing Winterization in Flint

Winterization in October takes 2 to 3 hours and costs nothing if your systems are in good shape. Winterization in January — when a frozen pipe has already burst — costs thousands. The difference is entirely timing.

Flint's housing stock adds specific complexity: gate valves that may have seized, galvanized supply pipe at the service entry that needs attention, and sump pumps that need to be confirmed working before snowmelt season, not during it.

Winterize Outdoor Faucets — The Right Way

The most commonly skipped winterization step is disconnecting garden hoses before closing the outdoor faucet. A frost-free sillcock is designed to drain internally when the faucet is closed — but only if the hose is disconnected. A connected garden hose holds water in the faucet body, defeating the frost-free design and allowing ice to form inside the wall.

After disconnecting the hose: locate the interior shutoff valve for the exterior faucet (typically in the basement near the hose bib location). Close it fully. Then open the exterior faucet to drain any water remaining between the indoor shutoff and the spigot. Leave the exterior handle in the open position through winter so any residual moisture can escape.

• Disconnect all garden hoses before the first frost — this is the single most important outdoor faucet step
• Close the interior shutoff valve for each outdoor faucet
• Open the exterior faucet handle after closing the interior shutoff to drain residual water
• If the interior shutoff is a gate valve that is hard to turn, note it for replacement — gate valves in pre-1960 Flint homes can seize after years of non-use
• Leave exterior faucet handle open (not closed) through winter

Insulate High-Risk Pipe Runs

The water service line entry point at the front foundation wall is the highest-priority insulation location in most Flint homes. Foam pipe insulation sleeves plus heat tape at this location — where the supply line passes through the rim joist area — provides the most freeze protection per dollar spent.

Any pipe running through an unheated attached garage, under-insulated crawl space, or against an exterior wall in a renovated room should be insulated before the first freeze. Foam pipe insulation is inexpensive and quick to install on exposed pipe runs.

Test Your Sump Pump in September — Not March

Most Flint homeowners test their sump pump in spring — right when they need it. The better approach is September testing: pour 5 gallons of water into the pit and confirm the pump activates, moves the water, and shuts off cleanly. Check the check valve (ensure water doesn't flow back after the pump stops) and inspect the float switch for free movement.

If the pump fails or runs sluggishly in September, you have time to replace it before snowmelt season. If it fails in March during peak groundwater period, you are competing for one of the most in-demand service calls in Genesee County.

Service Your Water Heater Before Peak Winter Demand

Michigan groundwater entering your water heater in winter is 35–45°F — compared to 55–65°F in summer. That is 40 to 50 percent more thermal demand placed on the heater every time hot water is drawn. An aging water heater that handles summer demand adequately may struggle or fail in January under that increased load.

Fall is the ideal time for a water heater flush (to remove sediment accumulation, especially in homes with galvanized supply pipes) and an anode rod inspection. If the unit is over 10 years old, evaluate it honestly before winter peak demand arrives.

Confirm Your Main Water Shutoff Valve Works

Every household member should know where the main water shutoff is (basement, near the front foundation wall in most Flint homes) and confirm it closes completely. Turn it fully off and then back on. If it is a gate valve that is stiff or does not fully stop water flow, replacing it with a ball valve before winter is a one-pipe project that takes an hour.

In a frozen pipe or burst pipe emergency, the main shutoff is your first action. Finding out it does not work during the emergency is the worst possible moment to discover this.

Unoccupied Flint Properties — What to Do

Any Flint property that will be unoccupied over winter should be maintained at a minimum of 55°F — the threshold that prevents pipe freezing in interior walls. If the property will be fully shut down, close the main water shutoff and drain the system: open the lowest faucet in the house, then systematically open all faucets from the top floor down to drain all water from supply lines.

Add plumber's antifreeze to all P-traps (sink, shower, tub, floor drain) to prevent trap water from freezing and cracking. Flint has an elevated vacant property rate, and freeze damage to unoccupied homes is entirely preventable with this checklist.