There seems to be a lot of confusion over that issue. Some places say the phone is IP67, others do not. There are videos of it dunked in water...
As myself and ir_bandito say, the defy mini is NOT waterproof.
The motorola manual states this too. P4: https://motorola-global-en-uk.custhelp.com/ci/fattach/get/434897/1337763040/redirect/1/session/L2F2LzEvdGltZS8xMzY5OTk0ODE5L3NpZC9veVRoVHlybA==/filename/DEFY-MINI_EN_UG_68016767006.pdf
"Note: Your phone is not designed to float or work
The Defy+ and original defy are IP67 (waterproof).
The mini does have some water resistance, but it's not supposed to be waterproof...(water may or may not kill it...)
Also see more comments here:
theirs stopped working after they dunked it thinking it was waterproof...