What to do if the phone you drop to the water

What to do if the phone you drop to the water
First thing, do not miss the calm and act fast, out of the water and remove the battery, the chances of recovering it decrease if it is long with battery; internal shorts could go so damaging and be unrecoverable after.

Then the best thing is to disassemble it as much as you can (on the internet there are many manuals on how disarm the different terminals) and warm with a hair dryer, but that is too hot to melt.
If he acted quickly, it likely that only it becomes submerged superficially. Remove the battery, and if you see him completely dry inside, you just have to dry it with a dryer. You've been lucky this time!

Once disassembled (without battery or SIM card, and loose everything you can) you can opt for the easy solution, which results most of the time, that is put it in a container closed rice for several days, at least a week if you have not dismantled much, or at least 3 days if you have separate parts, until it is dry. Rice is the desiccant (which absorbs the moisture) cheaper there.
It is more effective, if you have it, the silica gel, in the form of silicon dioxide pellets, a very effective moisture absorbent, and that they are often found in the form of bags of paper in shoe boxes, plugs of medications, some quality diapers (e.g. Dodot), etc.
If you turn on it rather than spend sufficient time, internal short-circuits (water conducts electricity) can damage it irreversibly, so you'll have to have patience; It is preferable to stay without moving a week to stay forever without it.

The other option, before put it in rice, is thoroughly cleaned the contacts with a toothbrush dipped in isopropyl alcohol (to remove matter in suspension in the water), and distilled algua (which does not have material in suspension that then produces false contacts).
Once this is done, and dried with dryer, to remove any moisture that may remain, you put it a few days in rice, and this will do the job of absorbing the rest of the moisture.

 In the following pictures you can see how the water sensor a Mini Gallaxy (a white paper which, with water or excessive moisture, becomes red) is activated; these cases are not covered by the warranty.

Samsung Gallaxy Mini disassembly
It has a connector to the screen that needs to be released, along with the House, to be able to separate the screen plate.

And in this way dry better everywhere.

Once released the screen plate, loose the 4 screws holding the plate that has to avoid interference; I am sure that drops of water inside. Use isopropyl alcohol and a toothbrush to clean of residual water and then apply the dryer well.
To be sure that not is nothing of humidity, leave it a few days disarmed in rice. Then clean it with a soft cloth with care and without mounting it, you can try to connect the screen and battery, holding it with one hand on your website against copper contacts, to test if you turn on by pressing the button on the side:

If so, you can ride it now!

In any case, if the mobile after being disarmed and dried completely, If it has been running with water inside may have suffered short circuits which damaged one of its microchips, leaving it unusable. In that case, the only way to fix it is to change all the motherboard, which juxtaposes more economical to buy a new one (the screen is one of the more expensive parts of the mobile). Luck!

And if do not want you to spend, consider buy a mobile water and dust-resistant as The Sony Xperia Z (but not think you immerse it in water to "prove" how it works its tightness... you've advised!:)