How long does a water leak detector last?
Updated August 2026
A wireless water leak detector lasts 3–5 years, and the battery is almost always what gives out first. The sealed coin or CR2 cell inside a puck-style sensor fades at the 3–5 year mark, and bargain sensors ($20–40) tend to go earliest; a hub-connected model ($60–100 per sensor) can push past 5 years but is only as useful as the smart hub it reports to, which itself ages out in 5–8 years. The other killer is corrosion: the exposed metal probes sitting in a damp spot pit and crust over, and a corroded contact can miss a leak even with a fresh battery.
Lifespan by type and situation
| Type or situation | Typical lifespan | Why |
|---|---|---|
| Battery puck sensor | 3–5 years | Sealed coin or CR2 cell; when it dies the whole unit is usually replaced |
| Hub-connected smart sensor | 5+ years | Outlives its battery, but only while the hub and app stay supported |
| Wired or flush-mounted probe | 10+ years | No battery to fail; the exposed contacts are the wear point |
| Whole-home shutoff valve | 10–15 years | The motorized valve lasts longest; its wireless sensors still need battery swaps |
| Probes in a damp pit or sump | 2–3 years | Constant humidity corrodes the contacts and drains the battery faster |
| Any sensor left low for months | Effectively dead | A silent detector protects nothing, which is why monthly testing matters |
Signs yours is near the end
- A low-battery chirp or a red status light on the sensor or in the app
- The test button no longer sets off the alarm or a phone alert
- Green corrosion, white crust, or pitting on the metal contact probes
- The sensor shows offline in the app for days, or stopped reporting in
- Water touches the probes and nothing sounds, the failure you least want mid-leak
- The hub or app has stopped getting security and firmware updates
How to add years
These sensors are cheap insurance, but only while they work. Testing each one monthly and swapping the battery the instant it reports low is the whole game, since a dead detector is worse than none. Work through the leak-sensor maintenance checklist to wipe the probes clean and clear any corrosion off the contacts, which is the second thing that kills them. If you are still deciding where they earn their keep, or what a water leak sensor actually does, the math is stark: a $20–100 sensor against the cost of skipping leak detectors and a flooded floor.
What it costs to replace: plan on $20–100 per sensor. Replacing on your own schedule, before it fails, is almost always cheaper than the emergency version. The home maintenance cost calculator helps you set the money aside before it comes due.
OnOtto tracks your leak sensor battery checks age and service history, and warns you before end of life instead of after the flood.
Track your home's systems, free for 30 daysFrequently asked questions
How often should I change the battery in a water leak sensor?
Most sealed sensors run 3–5 years on a single coin or CR2 cell, but you should not wait for the chirp to find out. Press the test button monthly and swap the battery the moment a sensor reports low, since a dead detector protects nothing. Hub-connected models show a battery percentage in the app, which makes the swap easy to schedule. Probes sitting in a damp basement or sump drain faster, closer to 2 years, so test those more often.
Do water leak detectors need Wi-Fi to work?
Two kinds exist. A standalone detector just sounds a loud local alarm when its probes get wet, and it works with no network at all, but only someone in earshot will hear it. A smart sensor pairs to a hub or Wi-Fi and pushes an alert to your phone from anywhere, which matters most for a vacation home or a basement nobody visits. The trade-off is that the smart version depends on the hub, the app, and your internet staying up.
Where should I put water leak sensors?
Put a sensor anywhere a slow leak would go unseen: under the water heater, behind the washing machine, beneath every sink, under the dishwasher and fridge, at the base of toilets, and in the sump pit. A typical house needs 6 to 10 of them at $20–100 each. If you want one line of defense, guard the water heater and washer first, since those two cause a large share of interior water-damage claims.
Are water leak detectors worth it?
For most homes, easily. A single sensor runs $20–100, while a burst supply line or a leaking water heater can dump hundreds of gallons and leave a $2,000 to $10,000 repair for flooring, drywall, and mold. Even a slow drip behind a cabinet can rot a subfloor over months. Detectors do not stop the water by themselves, but the early warning turns a catastrophe into a mop-up. See the cost of skipping leak detectors for the full math.