Water Leak Sensor Coverage Calculator
Figure out how many water leak sensors you need to protect your home’s at-risk spots, and the gap between what you have and full coverage.
How it works
Recommended = water heaters + bathrooms + appliance lines + other spots · To add = recommended − sensors owned
Leak sensors are placed at the points most likely to fail, not spread evenly by floor area, so coverage is counted per at-risk location: each water heater, bathroom, and appliance supply line gets its own puck. Add high-risk extras like a sump pit, an HVAC condensate pan, and behind any shutoff. Pair these spot sensors with a single automatic shutoff valve on the main and a small leak becomes a caught leak instead of a flooded floor.
Worked example
A home with one water heater, two bathrooms, three appliance connections (washer, dishwasher, fridge line) and two other spots (sump pump, HVAC pan) has 1 + 2 + 3 + 2 = 8 at-risk locations, so it wants 8 sensors. Owning 0 today, you are at 0% coverage and need all 8.
Frequently asked questions
Should I put a sensor in every room?
No — water damage starts at fixtures and appliances, so sensors go at those failure points: under sinks, behind toilets, at the water heater base, by the washer, and in the sump pit. Empty rooms with no plumbing do not need one.
Do I need a shutoff valve too?
A sensor only alerts you; a smart shutoff valve on the main line actually stops the water when a sensor trips or the flow looks abnormal. Pairing spot sensors with one automatic shutoff is the most effective setup for preventing a burst-pipe flood while you are away.
What about freezing pipes or slow drips?
Many leak sensors also read temperature and humidity, warning of freeze risk before a pipe bursts. For slow drips, place the sensor at the lowest point where water would pool, since even a small leak eventually reaches the floor.
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This calculator is for educational purposes. Double-check important results before acting on them.