A burst pipe in an occupied house is a bad afternoon. The same burst in an empty house running for four days is a different category of problem.
Do not turn the heating off
The instinct is to save money while away. In Washington winters this is how vacant properties end up with catastrophic damage.
Set the thermostat lower, not off. Above freezing with a margin, since interior temperature is not uniform and the crawl space, garage and exterior wall cavities run considerably colder than the room the thermostat is in.
East of the Cascades this matters far more, because sustained cold means a house without heat cools further and stays there.
Shut off the water
The most effective single measure for longer absences. If no water is entering the house, a failed pipe cannot flood it.
For extended absences, shutting the main and draining the system is worth the effort. For a week away, shutting the main alone removes most of the risk.
Know where the main is and confirm it actually turns before you rely on it. Valves that have not been operated in years sometimes do not.
The appliance connections
Washing machine hoses fail suddenly and are a common source of vacant-house flooding. Turn off the supply valves behind the machine.
Same for the dishwasher supply if accessible. These are the connections most likely to fail without warning, and they are under constant pressure whether you are home or not.
Have someone check
The single most valuable arrangement. Someone who goes inside, not just past the front of the house.
They should look for water, confirm the heating is running, and check the property is secure. During a cold snap or a windstorm, that check should happen promptly rather than on schedule.
Give them the location of the water main and your contact details. Someone who finds a problem and cannot stop the water is of limited help.
Before winter absences specifically
Make sure outdoor plumbing is already winterized — hose bibs drained, irrigation blown out. Those tasks do not wait for your travel schedule.
Check the forecast before leaving. A cold snap arriving while you are away changes what precautions are worth taking.
Longer vacancies
For properties empty for extended periods — second homes, rentals between tenants, properties being sold — the calculation changes.
Draining the system properly is worth it. So is checking whether your insurance has conditions relating to unoccupied properties, since many policies do and they can affect cover after a defined period. Worth knowing before rather than after.
Consider a monitored temperature or water sensor. These are inexpensive relative to the damage they prevent and they alert you before someone happens to visit.
Summer absences
Less risky but not risk-free. Appliance connections still fail. Consider turning the water off anyway.
West of the Cascades, a house closed up through summer can develop humidity problems, particularly with an existing crawl space issue. Some airflow is worth arranging.
What actually matters
Heat on, water off, someone checking. Everything else on this list is refinement. Those three prevent most of what goes wrong.