Water leak detectors: stop a burst pipe flooding the empty house
According to OCU, citing ICEA data, water damage accounted for over 37 % of home insurance claims in Spain in 2022. In an occupied house it is seen within the hour. In an empty house, a burst flexible hose can run for weeks.
Step one: turn off the stopcock when you leave
It is free and it protects the most. If the pool or the irrigation need water while you are away, leave only that branch open and close the house one, if your plumbing allows it.
Step two: a sensor that alerts you
A water sensor sits on the floor, under the water heater, the washing machine or the sink, and sends an alert to your phone when it gets wet. Example: the Shelly Flood Gen4, 34.90 € with VAT on Shelly's official store. It runs on batteries and connects over wifi.
The alert is only useful if someone can go and turn off the water: a neighbour, your cleaner or your property manager. Leave them a key and show them where the stopcock is.
Step three: the valve that shuts itself
A motorised valve on the water inlet, linked to the sensor, shuts the water off by itself as soon as it detects a leak. Example: the Ajax WaterStop 1/2", 210.92 € with VAT, which also needs the Ajax hub (not included). Fitting it on the pipe is a plumber's job.
What they all need: a connection
A wifi sensor in a house where the router is off, or where there is no line, alerts nobody. Before buying, make sure the house stays connected when you leave. If it has no internet, read «Internet in a holiday home».
Check your policy: some home insurers require the stopcock to be closed when the house is left empty. A sensor does not replace that condition if your policy sets it.
Where the figures come from
Prices checked in September 2026. They change: take them as an order of magnitude and always ask for the final price in writing.
Questions about this
Where do I put the sensors?
What if the power goes off?
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