How often should you wash your house?

Most homes need a wash every one to two years. That’s the honest answer, but where your house sits in that range depends on a few things you can check in five minutes.

The short answer

If your walls look clean from the street, you can probably wait. If you can see green on the north side, black streaks under the gutters or a grey film on the windows, it’s time.

What changes the timing

• Shade and trees. Damp, shaded walls grow algae much faster.

• Water nearby. Homes near lakes, rivers or the coast need more frequent washes.

• Wall type. Render and painted siding show dirt sooner than brick.

• Which way it faces. North walls stay damp and turn green first.

A soft wash kills growth at the root, so a clean wall stays clean for much longer than a pressure-washed one.

How to make it last longer

Keep gutters clear so water doesn’t run down the walls, trim back shrubs so air can move, and rinse off bird droppings or pollen when you see them. Small habits add months between washes.