Every time there's a flood, a burst pipe, someone spills something on their laptop, or a drive is fished out of a bag that went in the canal, people immediately assume that all data will be lost. Usually, that isn't true. Water is a lot easier on a hard drive than either fire or an extreme drop. A water-soaked drive that is treated with the right care has a good chance of surviving. But treating a water-soaked drive with "the right care" means doing the opposite of most of your first instincts. Here's what can be recovered from a water-damaged hard drive, and how you need to handle it.
The file storage platters generally remain intact after a soaking. It is turning on the drive (or drying it incorrectly) once it is wet that will damage it, not the water itself.
In a hard drive, your files are stored as magnetic patterns on the rigid platters sealed within the drive casing. The magnetic patterns do not concern themselves with being wet. The water simply sits upon the surface of the platter and does nothing to remove or alter any information stored. In fact, almost all drives retrieved from flooded areas retain their data. This is an important point to remember when things look so bad: your data is very likely still there. What water presents a risk for isn't your data, it's the drive's ability to be read: the electrical components, mechanical components, and all of the extremely precise tolerances required to successfully spin up and properly track on the platters. If the drive is sent to a professional capable of reading the platters safely, then your files should be recoverable. Failures happen in the gap between the spill and the recovery, and that is where the next few points matter.
The two main causes of a water-damaged hard drive being ruined, both of which could be avoided, are powering it on and corrosion. Powering on the drive will allow an electrical path through the moisture on its circuit boards; this may short out some of the internal components, and it often kills them outright. If you turn on the drive with contamination (dirt or grit) on the platter surfaces, then the motor that drives these platters spinning can drag the contaminants across the platter and cause the very physical damage that would destroy your data. Corrosion also occurs when water evaporates from a surface. This corrosion can occur quickly or over time. For example, if you leave a drive that was exposed to saltwater or a fizzy drink to sit in a cabinet for weeks, the corroded contacts and platter surfaces can be far past the point of easy recovery. Thus, time and electricity are your enemies, not the water. That is why the right response is counterintuitive.
Almost all of the instincts here are wrong. Do not turn it on to "see if it still works", as this will result in losing more data than the water itself. Don't use heat to attempt to dry it. A hairdryer, radiator, airing cupboard or even an oven can warp the components inside your hard disk and bake contaminants onto the platters. The bag of rice (which has been debunked) won't do much at all for a sealed drive other than drop starchy dust into the internal mechanisms. Don't open the drive to allow it to dry. Room air is dusty enough to be detrimental to an exposed platter. And please don't let it sit for weeks and then hope it will be okay. That simply allows corrosion to get started. All of these actions can turn a recoverable drive into a harder recovery, or even make the recovery impossible.
The correct option for handling your hard drive is also less stressful: let it sit with some moisture to it and get it to a lab. If the drive still has moisture in it, do not attempt to dry it, as an uncorroded drive that sits with moisture will often be in much better condition than one left to corrode, since the corrosion process has been denied this opportunity. Place the drive in a sealed plastic bag, preferably with a small amount of the original water or a damp paper towel inside the bag so that it does not dry out, and get it inspected quickly. At the laboratory, the damaged drive is placed onto a workbench and opened, the platter(s) will then undergo cleaning, which often includes using ultrasound, and the drive will be dried according to very strict guidelines. Following drying, the platters will be imaged on functioning hardware (usually bypassing or replacing the electronic components). While there are many variables involved when attempting to recover data from a water-damaged drive, if done immediately and appropriately after being submitted for evaluation, the chances for successful recovery of the information contained within are genuinely good. We provide such services via our water and fire damage recovery service, and it starts with a free diagnostic.
Unlike hard drives, SSDs, USB sticks and memory cards do not contain platters, as they store data on flash chips. The same rules apply doubly: do not power it on, do not heat it up and just get it in. As memory chips usually survive, if there was corrosion to the board, we may still be able to pull the data directly from the chip. Laptops that have taken a spill are another area altogether. They may have perfectly good storage but will not boot because of the damage caused to something surrounding the drive. It's therefore the drive we need and not the laptop. We do not recover mobile phones, tablets or the storage which is soldered onto laptops. The main link among all of them is the fact that water is survivable; it's usually the wrong first action that is fatal. If your drive has had a bath, leave it turned off, bag it and use a free diagnostic service to tell you how much remains: get a quote first, either by telephone or using the contact form, before bringing it to our South Gyle drop-off centre, Monday to Friday 9am to 5:30pm, without needing to book an appointment, or posting it to us from anywhere in Scotland.