I'm testing the same one (sold as the Ewelink brand) on ST using the built in drivers. Works fine so far. Battery life isn't as long as I would like, but they're just using a CR2032.
I ordered them from Ewelink Zigbee Smart Home Water Leak Sensor Wireless Flooding Detector Water Leakage Detection Alert Water Level Overflow Alarm|Sensor & Detector| - AliExpress. ~$16 US/each.
Another favourite zigbee leak sensor with HE is the linkind mentioned here. Linkind water leak detector $15 Love the two AAA batteries.
