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Water leak sensors: cheap insurance for landlords

A small sensor can warn you of a leak before it reaches the neighbours’ ceiling.

Where to place them

Under sinks, behind the toilet, near the water heater and washing machine, and by the dishwasher.

What to check

Make sure alerts reach your phone, not only a local beep, and that you get a low-battery warning. Test each sensor with a damp cloth after setup.

Which type to choose

A standalone leak detector sounds an alarm when it touches water. It is cheap but sends nothing to your phone, so it only helps if someone is there. A smart leak detector connects to the internet and sends alerts to your phone, which is what a host needs. Whole-home systems on the main water line can monitor flow and, in some setups, shut the water off automatically.

Where to place them

At the lowest point where water would pool: under kitchen and bathroom sinks, next to the washing machine and dishwasher, beside the toilet, and near the water heater. Keep the sensor clear of anything that could stop it touching water.

Browse smart Wi-Fi water leak sensors on Amazon

We have not listed specific models here yet. The sources we found describe types of device but do not compare products reliably. We will add tested picks later.