What should I do?

First of all, take your cell phone out of the water as soon as possible. Next, remove all detachable parts: battery, SIM card, case etc. If your phone has been dropped in salt water, rinse with clear water, otherwise the salt could damage the cell phone.

After, drain and pat dry gently your cell phone. Once it’s done, take a bag or a dish fill up with uncooked rice or silica and place your phone in it. The rice or silica will absorbed all the moisture that would have remained in the tinny areas you can’t reach. Wait 24 to 48 hours before attempting to restart the phone. After the delay, grab your cell phone, cross your fingers and turn it on.

What should I NEVER do?

• Try to turn on your cell phone right after the plunge in the water.

• Don’t shake it either softly or roughly to remove the water in it.

• Never put it in the oven (even with low temperature), in the microwave or blow-dry it!! It could melt the circuits of your cell phone.

Source: Popular Mechanics article