There are 2 types of loggers: NFC, which are waterproof, and RF.
RF loggers are IP67 certified (can be immersed in water up to 1 meter for up to 30 minutes).
However, it is not recommended to subject them to a powerfu jet of water like karsher, chemicals, or to let them lying down in contact with a liquid. In the same way, too much humidity will damage the recorders.
Washing tip: Use a damp cloth.