In computer forensics, and data recovery, it is not unheard of to come across hard drives that have got wet, and not always accidentally. In one year, the same police force, had to recover several hard drives that had deliberately been thrown into the sea – along with the rest of the laptop.
As this type of recovery is more often than not outsourced to the civil sector this leads to the question: Does water destroy a hard drive?
Water alone is not harmful to data. If the hard drive is off, and not spinning, the water will not destroy the data. The data, after all, is stored magnetically on the platters, this is not going to lost by the addition of water.
Firstly hard drives are pretty well sealed, so a quick dunk in the water is unlikely to effect the hard drive itself. Secondly, even if the hard drive is left in the water, or sea for a long time, all is not lost.
What is important is the drying process. If a hard drive has been left in the sea or dirty water for a couple of days, and is then dried out, this is not going to work straightaway, and powering it up could be damaging. The reason for this is that the salt or dirt that is left behind once the water has evaporated will stick to the platter, as the platters spin up (if that even happens) there could be damage to the surface of the platter – which will damage the hard drive.
Once the drive has been wet for a period of time it is recommended that the drive is taken to a specialist recovery company (ideally while its still wet and before its been dried out). The company will then clean the platters professionally. Even if the entire hard drive casing is damaged/destroyed they can put the platters into a new casing and recover the data that way.