Recommended Leak Detector

If you have a zigbee network the aqara leak detector is a good option. It doesn't require a hub, cloud or any setup. And if you are willing to wait you can get them on AliExpress for a lot cheaper than Amazon.
- I have a few of the Aqara leak detectors and they have worked well.
  They also have screw terminals that you can attach wires onto to extend the detection area/range. I’ve also seen people attach contact or pressure sensors to them, they are nifty devices.
- That's a good callout. When I said you need a zigbee network I guess I should have specified an antenna.
  My point is that you don't need the aqara hub, because sometimes people think it's required.

I have a couple of these Zooz Z-Wave water detectors. They were recognized by zwave2js, and easy to set up and test. My only issue is that I get triggers from them whenever the Z-Wave network changes - like, when I add new devices, I get an alarm from them.
They're tiny - like the size of an old box of (matchstick) matches. If they were cheaper, If put one under every sink.
- I had a similar issue with other zwave sensors. With a little help I was able to refine my triggers so that my automations only run when they go from an “off” state to an “on” state. Before that they’d trigger from a “none” or “unknown” state, which is what happens when HA or zwave2js restarts.
  
  Ah thanks! These are the only ZWave I have that does this - I'll check that!

an esp8266 (or esp32 if you have on laying around) and a long wire. cut that in half, remove the insulation from the ends, wire one to ground and one to any output pin on the esp. detect when the pin gets shorted (basically a button activated by water). use esphome and the button input.
- Probably need to look for less than a short. Water is conductive but not THAT conductive.

After a water heater leak I just made my own. I run my HA on a Raspberry Pi, so I connected the GPIO pins to a current-limiting resistor and some wires that I put in the drip pan of my water heater. I made the two contacts using a screw connector, and hot glued it in the pan. You can also do this with an ESP chip. Additionally, I integrated my smoke detectors through an optoisolator and connected all my hard-wired door and window sensors to the GPIO. It's been working great this way for me.

THIRDREALITY Zigbee Water Leak Sensor. I got it off amazon $20 works great with ZB2MQTT I have it under my AC unit in the garage incase the drain gets plugged and condensation goes crazy. It beeps loudly when it detects water so if something is up with your HA or zigbee network, it still alerts someone. I would buy another one, prime shipping and not too expensive.
- I have six all around my house, same setup using Z2M, haven't had any issues

I bought the Govee leak detectors and paired them with a Tasmota flashed Sonoff RF Bridge 433. They’ve already saved me multiple times from leaks that would’ve gotten out of control without me being notified. The Sonoff Bridge can’t be flashed with Tasmota as readily as before but you can probably find a compatible version somewhere
- I can't seem to find the rf bridge in stock anywhere, where did you buy yours?
  
  I see quite a few on eBay. I would ask the seller if it has an ESP Wi-Fi chip to be sure it can be flashed