In case the phone fell into water there is a high risk of short circuits due to the electrical conductivity of water. This does not only cause damage to the parts but can also lead to an overheating of the battery. Over a longer period of time the power supplied from the battery to the circuits causes a reaction resulting in corrosion of the circuits (remember electrolysis experiments in school, two nails in glass of water, wired to a battery?) and failure. Therefore the first action we should take is to
Immediately remove the battery
Do not try to operate the device. It will make things worse for sure.
Remove all water
After having removed the battery we have to get rid of all the water in the device.
- Remove all parts (SIM card, memory cards, headsets)
- Open the case and dismantle as many parts as you can
- Remove gross water drops with a dry towel or handkerchief.
- Patiently let the device dry at room temperature for several days (time needed depends much on the environmental humidity where you live).
Tips for taking a phone apart:
- try to remember, or take pictures, to be able to get them back together again. You may need to use a fine screw driver for this.
- Keep the screws in a safe place and note down where they go - modern phones use many different lengths and widths of screw. Draw a basic picture of the phone on paper and place the screws in the same place on the picture as you remove them
- Consider putting screws gently back into the same holes they came out of, after you have removed the part they were securing, if the phone will be in bits for a while
- Follow a YouTube video tutorial of how to take you particular phone apart. Search for "iphone 6 tear down" or "dismantle galaxy s8" for more
- remember that a YouTube video might be done on a phone that has been taken apart before, and might have been put back together wrong. Many videos of the iPhone 6 teardown, for example, have the screen ribbon cables in the wrong order. Your phone's presentation should override the video. Also bear in mind that popping the screen off a phone gets easier the more times it's done so the video may look like the screen just falls off when it actually needs a good pull. Watch a few
Remove salt or sugar
In case it fell into salt water, soup or beverage we have to remove salt or sugar too to avoid later corrosion or short circuits. This can be done by immersing all parts except the battery in a bath of distilled water.
Accelerate the drying process
There are several ways to accelerate the drying process. Use any but do not use the sun, an oven or a hair dryer - the heat may damage your device.
- Put all parts in an air tight bag with a water absorbing substance for some days (at least 2). This could be rice or silica gel bags (which come in the packages of many electronic devices) but do not use salt because of its corrosive potential.
- Immerse all parts (except the battery) in isopropyl alcohol. This will solve all remaining water and it then evaporates much faster than water alone. There is a small risk however to damage non-alcohol resistant glued parts by this.
- Professionals use a vacuum chamber for rapid water removal but we mortals may have no access to that.
What if the device still does not work?
Well, then you should know that you are not alone. Only a fraction of phones will survive from being drowned. Unfortunately due to moisture detectors within the devices your warranty will be void in any case.
Sadly from newer devices the battery can no longer be removed. Therefore the chances for rescue are much smaller. In many cases though, the battery will have a connector cable that can be unplugged. You'll have to open the phone up and look for it. Again a video tutorial found via a search like "change iPhone 6 battery" will provide the minimal set of steps needed to disconnect the battery