ShellyFlood Wireless Flood Sensor with Temperature Measurement, Drip and Leak Alarm, Underfloor Heating Control, Compact Design, Easy Operation, Battery Life up to 18 Months

I disagree that these are difficult to set up or are unreliable.When you place the battery, they immediately start an WiFi AP and you can connect to it and configure it in the browser on your phone without any app.Once joined to WiFi it powers off into low-power mode and seems to wake up once per hour to read temp, connect to wifi, etc. Home Assistant picks them up right away, and you can set app alerts using `Automations` with `Trigger -> State` then `Action -> Mobile App Notification.`This is how an ESP8266-based low-power device should work. It wakes up immediately if the contacts are shorted (flood), and the status is alerted in Home Assistant within seconds AND has a nice loud alarm, but otherwise it's in standby mode.The only real downsides are the size, and the non-standard battery. Looking at the internals, I can't see why they made them so big. Also, since they are rarely "on", doing any kind of admin on the web UI requires you to reinsert the battery to force it on, otherwise it's unreachable on the wifi network unless you happen to go to the IP address right during the wakeup schedule for the 30 seconds it's awake every hour.I think the convenience of having it be WiFi vs Zwave or Zigbee may be worth the tradeoffs so you don't have to worry about failure of your Zigbee or Zwave gateway while your house is flooding. Wifi pretty much always works.

Shelly makes no claims this product works with Google Home, but I am hopeful it will be added in the future. The install was easy. I had to try several times to pair it with the app. I would reccomend leaving the top off until it's fully paired and updated.These are cheap enough that I wouldn't have a problem having one near every water source. And they are small enough they could easily slip under a dishwasher.

I use it for both temperature sensing and flood sensing.

I purchased several of these flood detectors to add to my home system. I also have several older smarthings flood detectors as well. The Shelly detectors work great but have a few notable limitations. The first is the contact points on the bottom of the sensors make direct contact with whatever its sitting on. In my case and like most other homes it is sitting in a metal drip pan under the water heater. Since the sensor contacts only measure a completed circuit, when they sit on the metal drip pan it immediately triggers an alarm. I solved this issue by placing a piece of plastic under each sensor. The second issue is a very short battery life. My first set of batteries only lasted 3 months. Two of the Shelly sensors are placed next to Smarthings sensors which have batteries that have lasted over a year.

I tried everything called att got a new modem. Trying to get this flood sensor to connect to my wifi, all i got was a test of my patience that got stress thin. Don't waste your time or money.