While it might seem as if it’s a good way to ruin electronic equipment, you cannot destroy the information on a hard drive and deem it unusable if you submerge it in water.
Why is that? Well, the water will short circuit the electrical components of the hard drive, but the data will remain.
You can easily wipe the water off the hard drive and access the information still contained on it. The only way to ensure your information is protected is to use one of the methods we’ve outlined above.
You’ve probably heard that you shouldn’t place magnets anywhere near hard drives.
The magnets used to destroy hard drives (and CDs and DVDs) are very powerful. So powerful that it’s not advised you use one if you’re not a professional.
No doubt you can read about a lot of hard drive destruction methods online, but not all of them work. Your best bet is to have your hard drive destroyed by a professional.
However, if you want to make sure a hard drive is unrecoverable, then the platters of the hard drive must be unspinnable and demagnetized. You should never burn a hard drive (it has a lot of toxic chemicals) or use chemicals on it that can release toxic fumes. Other common DIY methods, like using a drill, it’s still possible in some cases to recovery some data.