I have a large lot of Vivint water sensors.  These work perfectly.  I unpaired them from my system, before I decommissioned my Vivint system.
I have also cleaned them all with Clorox to ensure they are sanatory (as they have been sitting under sinks for a year).
You can see by the picture, they look brand new, even though they are at least two years old.
Batteries are included, however, batteries are not new.   The batteries test good though.

These use 345MHZ radio.  They are NOT compatible with SmartThings, Alexa, or Google Home.