How to prepare your plumbing before a holiday

The thing that makes holiday plumbing failures expensive is not severity, it is duration. A supply line that fails while you are in the house is noticed in minutes. The same failure on day two of a fortnight away runs for twelve days.

Before you leave

1. 1Shut the main water off. For any trip longer than a weekend this is the single highest-value action, and it takes thirty seconds.
2. 2If you cannot shut the main — an irrigation timer, an ice maker you want running — shut off individual fixtures instead, particularly the washing machine and dishwasher valves.
3. 3Check the washing machine hoses. Rubber hoses have a service life and they fail by bursting. If they are older than five years, replace them with braided stainless before you go.
4. 4Look under every sink with a torch. Any dampness, any corrosion on a fitting, any staining on the cabinet base is a leak you have not noticed.
5. 5Run every drain briefly and confirm it is flowing properly. A drain that is already slow is the one that backs up while you are away.
6. 6Set the water heater to its vacation or lowest setting. No sense heating water for an empty house for two weeks.

The traps problem

Every drain has a water-filled trap that blocks sewer gas. In dry heat over a couple of weeks, traps in rarely used fixtures evaporate, and you come home to a house that smells of sewer.

Before a long trip, pour a cup of water into every floor drain and any unused fixture, then a tablespoon of cooking oil on top. The oil floats and dramatically slows evaporation. It clears the first time you use the drain.

If you are on septic

• Do not run the washing machine repeatedly the day you leave. A sudden hydraulic load is the worst time for one
• If a pump-out is already due, book it before rather than after — coming home to a full tank is a poor start
• If anyone is house-sitting, tell them it is septic and what that means for what goes down the toilet