A smart water leak detector is a small sensor that sits on the floor and sends an alert to your phone the moment it touches water. Many work over home Wi-Fi with no monthly fee, so you hear about a leaking water heater or washer hose even when you’re away. Setup usually takes about 15 minutes.
Quick answer: Buy a Wi-Fi leak sensor that doesn’t require a subscription, install its batteries, pair it with the maker’s free app on your home Wi-Fi, turn on phone notifications (and text or email alerts if offered), test it with a damp paper towel and place it on the floor near the water heater, washer or sink.
Why a leak detector matters
Leaks waste a surprising amount of water. EPA WaterSense estimates that the average household’s leaks can waste more than 9,300 gallons of water a year, and that 9 percent of homes have leaks that waste 50 gallons or more per day (EPA WaterSense). Nationwide, household leaks can waste nearly 1 trillion gallons a year.
Slow, hidden leaks under sinks or behind appliances often go unnoticed for weeks and can damage floors and cause mold. A sensor that alerts you right away lets you shut off the water fast, which protects your home and saves water. That matters even more in drought-prone states like California.
What you need
- A Wi-Fi water leak sensor with free app alerts and no required subscription
- The batteries it uses (often included)
- A smartphone with the maker’s free app
- Your home Wi-Fi name and password (many sensors use the 2.4 GHz band)
- A damp paper towel for testing
How to install a smart leak detector
- Pick a no-fee model. Read the product page to confirm alerts are free. Check whether it offers push notifications only, or also text (SMS) or email alerts, and whether it needs a separate hub.
- Add the batteries. Open the back cover, insert the batteries and listen for a beep or watch for a light that shows it powered on.
- Download the free app and create an account.
- Pair the sensor. In the app, tap to add a new device, choose the water leak sensor and follow the steps to connect it to your Wi-Fi.
- Turn on alerts. In the device settings, allow app notifications so alerts show up even when your phone is locked. If the app offers SMS or email alerts, add your phone number or email for a backup. Some sensors can send texts through free smart home services or routines.
- Test it. Touch the metal probes on the bottom with a damp paper towel. Your phone should buzz within seconds, and the sensor should sound an alarm.
- Place it where leaks start. Set the sensor flat on the floor, probes down, near the water heater, under the kitchen sink, behind the washing machine, near the dishwasher or by the toilet.
Tips
- Know where your shutoff valve is. An alert only helps if you can turn off the water quickly. Find your main shutoff and the valves under sinks and toilets.
- Check batteries. Most apps warn you when batteries are low. Test the sensor every few months.
- Use more than one sensor. One sensor covers only the spot where it sits.
- Keep it reachable. Don’t wedge it so deep behind an appliance that you can’t change the batteries.
Frequently asked questions
Do smart water leak detectors need a subscription?
Many do not. Lots of Wi-Fi sensors send free push alerts through the maker’s app. Check the product details before buying, since some brands charge for extra features like professional monitoring.
Can a leak detector send a text message?
Some can send SMS or email alerts directly, and others only send app notifications. App push alerts work much like a text, and some sensors can trigger texts through free smart home routines.
Where is the best place to put a water leak sensor?
Put it on the floor where leaks are most likely: next to the water heater, under the kitchen and bathroom sinks, behind the washing machine and near the dishwasher or toilet.
How long do leak sensor batteries last?
It depends on the model, but many last a year or more. The app usually warns you when the battery is getting low.
See your water impact
Want to see how leaks, showers and outdoor watering add up in your home? Try our free Household Water Simulator to estimate your water use and find the fixes that save the most.
Related guides
- How to Install a Faucet Aerator to Cut Water Use
- How to Convert an Old Toilet to Dual-Flush
- How to Set a Sprinkler Timer Once and Never Touch It Again
Sources
- U.S. EPA WaterSense, Fix a Leak Week
- U.S. EPA WaterSense, Statistics and Facts
Written and reviewed by the Accessible Sustainability Alliance editorial team. Last updated October 5, 2026.
