What to do in the first ten minutes of a leak

Turn the water off at the stopcock. Cut the power to the water heater. Move what you can and put towels down. Photograph everything before you mop it up, because your insurer will want to see it. Then ring a plumber. In that order.

Find the stopcock before you need it

This is the one thing worth doing today rather than during a flood. In a Spanish apartment the stopcock is usually in a cupboard near the front door, in the bathroom, or in a small hatch in the hallway ceiling. In a villa it's often outside, in a box near the meter or by the boundary wall. Find it, turn it, make sure it actually moves. Plenty of them haven't been touched in fifteen years and seize solid, which is a much better thing to discover on a calm Tuesday.

If you rent, or you're in a building with a concierge, ask where the mains valve for your flat is. Write it down somewhere you'll find it at midnight.

Then the electricity

Water and wiring share more walls than people think. If the leak is anywhere near a light fitting, a socket or the water heater, switch that circuit off at the consumer unit. An electric water heater sitting empty with the power on can burn out its element in minutes, which turns a leak into a leak plus a new heater.

If water is running through a ceiling light, leave the room and kill the power to the whole flat. Nothing in there is worth a shock.

Photograph it before you clean it up

Insurers and community administrators both want evidence, and both want it from before the mopping started. Take wide shots that show which room it is, then close ones of where the water is coming from and what it has reached. If it's coming through from the flat above, photograph the ceiling and tell your administrator the same day.

What to tell me when you call

Whether the water is off. Where it's coming from, if you know. Whether it's clean water or from a drain, because those are different jobs and different vans. And whether anyone is in the property. That's usually enough for me to know what to bring and how fast I need to be there.

Call rather than message if water is actually running. A message can sit unread for ten minutes; the phone can't. The number is +34 600 080 298.

If you can't find where it's coming from

Turn the water off anyway and leave it off. A leak you can't see is usually under a floor or inside a wall, and hunting for it with the mains on just adds to the damage. That's what leak detection is for: thermal imaging finds it without anyone knocking holes in a wall to look.