Pre-Vacation Plumbing Shutdown Guide — Protect Your Home While Away

Washing machine supply hoses are under constant pressure and are the #1 cause of catastrophic residential flooding. Turn both the hot and cold supply valves behind the washing machine to the closed position. These are typically lever-style (quarter-turn) or wheel-style valves on the wall behind the washer. If the valves are old and difficult to turn, don't force them — consider shutting off the main supply instead. A burst hose at full pressure floods a home with 500+ gallons per hour.

In winter, dropping the thermostat below 55°F risks pipe freezes in exterior walls and poorly insulated areas. In summer, turning off AC allows humidity to rise, encouraging mold growth and condensation on cold water pipes that can drip and cause damage. Leave the HVAC running at energy-saving but protective settings: 55°F heat minimum in winter, 80°F cooling maximum in summer. The energy savings from full shutdown are minimal compared to the risk.

Walk through the home and check under every sink, behind every toilet, around the water heater, and at the washing machine connections. A small drip that's ignorable when you're home becomes significant water damage over 5 days of unattended dripping. Fix any active drips before you leave or shut off the supply to that fixture. Also check the toilet for running — a stuck flapper can waste 1,000+ gallons over a 5-day trip.

Closing the main shutoff valve eliminates all flood risk from supply-side failures (burst hoses, failed supply lines, cracked fittings). Locate your main shutoff — typically in the basement near where the water line enters the home, in a utility closet, or at the water meter. Turn it fully closed. Then open a faucet on the lowest floor to relieve residual pressure in the system. This single action prevents the vast majority of vacation water damage scenarios. Note: your toilets won't refill after flushing with the main off — this is expected.

With the main water supply off, there's no reason to keep 40–80 gallons of water at 120°F. Most water heaters have a 'vacation' or 'pilot' setting that maintains the pilot light (gas) or turns off the elements (electric) while keeping a minimal standby temperature. This saves energy and reduces wear on the tank. For electric heaters, you can turn off the breaker entirely. For gas heaters, set to 'vacation' or 'pilot' rather than turning off completely (relighting a gas water heater requires proper procedure).

Food waste left in the garbage disposal or drain traps decomposes while you're away, creating severe odors and potentially attracting pests. Run the disposal with cold water until clear. Pour water down every drain (including floor drains) to ensure P-traps are full — an empty P-trap allows sewer gas into the home. For trips over 2 weeks, pour a tablespoon of vegetable oil into infrequently used drains to slow evaporation of the trap water.

Even with the main water off, sewer backups, sump pump failures, and HVAC condensate issues can still cause water damage. A trusted neighbor, friend, or house-sitter who walks through every 3–5 days catches problems before they become catastrophic. Ask them to check: no standing water anywhere, no unusual odors, HVAC is running normally, no signs of leaks from the ceiling or walls. Their phone number should be your first call if a smart home sensor alerts.

Close the main shutoff and open faucets at the highest and lowest points in the home to drain the supply system. Flush toilets to empty the tanks (pour RV antifreeze into the bowls and tanks if freezing is possible). Open the water heater drain valve briefly to relieve pressure. This removes most standing water from the supply system, eliminating not just leak risk but also stagnation and bacterial growth in standing water during your absence.

For absences over 3 weeks, shut down the water heater entirely. Electric: turn off the dedicated breaker. Gas: turn the gas valve to 'off' (not just 'pilot'). A water heater running without fresh water circulation for weeks wastes energy and accelerates sediment buildup. For gas units, know the relight procedure for your return — or schedule a plumber to reactivate if you're uncomfortable relighting the pilot.

P-traps in every drain hold water that can evaporate during extended absence, allowing sewer gas into the home. In cold climates, the trap water can also freeze and crack the trap. Pour 2 cups of non-toxic RV antifreeze (propylene glycol) into every drain: sinks, showers, tubs, floor drains, and washing machine standpipe. The antifreeze sits in the trap, doesn't evaporate, and protects against freezing down to -50°F. Use only RV/plumbing antifreeze — never automotive antifreeze.

Smart leak detectors ($25–$80 each) alert your phone when they detect water — even when you're thousands of miles away. Place them: at the water heater base, under the kitchen sink, behind toilets, at the washing machine, and near the sump pump. Combined with a trusted local contact who can respond, sensors provide early warning that limits damage even when you can't physically intervene. Some homeowner's insurance policies offer premium discounts for smart water monitoring.