Comment by bluGill

Most electronics are just fine. A few capacitors, and LCD displays are not fine with water, and probably a few other things I'm not aware of. However most electronics parts are encased in plastic or ceramic and just fine. In general mineral build up from washing in tap water once or twice is not significant, though if you are talking about hundreds of washings it will become a problem (depending on the quality of your local tap water). Deionized water is best if you can get it, but even that will harm a few components.

In general if you can wash it once (meaning components that cannot handle water are not used in this), the screws rusting out will be the next thing that gets you from washing.