Over the years, we have recovered data from thousand of makes and models of mobile phones. Not every case is recoverable and depends on levels of damage. In most cases where there has been water damage, this has generally been accidental. Dropped down the loo is probably up there in terms of percentages. Technology to improve erosion and damage to mobile phones is pretty good at the moment however, there is a difference... Water resistant is just that, resistant to water but, only to low levels of water and shallow depths. If you drop your phone in water and swoop it out within a reasonable time, the resistance may be enough to keep the water at bay. Waterproof means, your phone is more likely to sustain water for a much longer length of time and depth. Either resistance should be enough time to dry the phone out (remember, not to use rice).
We see a lot of mobile phones that have been in sea water too for different lengths of time and depths. 3EF are still able to recover data from seawater damaged mobile phones. Our success rates are fairly high in terms of getting the data, we cannot ensure the phone will be fixed however, the data is usually of the most important value.