Just recently looked at this myself. I ended up finding the Third Reality zigbee leak sensor on amazon.
You can find my review and pictures on amazon listed by chris b
Don’t really write reviews, but decided after reading everyone else’s I would. I bought these after seeing the good reviews with smartthings. I previously had leaksmart sensors from my Wink system but they always seemed to disconnect. I decided to see what hardware I had that could be used to lengthen the screws to below the device. I found that a M2x16mm cap head screw with a nut put the sensor up off my bench. I also noticed that they connected by default as a cloud connection so I tried the smart sense moisture sensor and although they don’t have temps they work great locally. I decided to give 4 stars overall since I had to change the cover hardware to give it a better chance of sensing light moisture.