It is sometimes possible to fix a water damaged cell phone using a cloth, heat, or some rice. These methods do not always work, but they might if the water hasn't seeped too deeply inside to the inner workings of the phone. For this reason, the chances of repairing a water damaged cell phone may be greater when repair attempts are made immediately. The longer you wait to try and fix your cell phone, the more likely it is that the phone will not be repairable.
As soon as you notice your phone has either dropped into water or has gotten water on it, you should take a cloth to it and wipe it off. Additionally, you should probably remove the back of the phone so you can take out the SIM card and battery. Place the phone, SIM card, and battery onto a paper towel so the water can completely drain. After a couple of hours, you can put the phone back together and turn it on. If the phone will turn on, you can try to make a call to be sure it is working properly.
If you put your water damaged cell phone back together and it won't turn on, it is likely that some water has gotten down inside the phone. When this happens, you may still be able to repair it using rice. You can remove the battery and SIM card from the phone once again and place all three components into a bowl filled with rice. This may work because rice is very absorbent, and it sucks in almost all water it is exposed to. Leave it all in the bowl overnight, and in the morning your phone may be working again because the rice will have absorbed any excess moisture you were not able to get out.
You could also use heat to dry out a water damaged cell phone. If the rice method either did not work or you don't have rice on hand, you can take the phone apart and lay all its pieces outside in direct sunlight for several hours. The heat from the sun may completely dry out the inside and outside of the phone and its parts. If it is raining or the sun is not out, you can place the phone directly on top of a heat vent or use a blow dryer on low heat to get the same results.
Keep in mind that if you try to take the phone apart and remove more than just the battery and SIM card, you run the risk of voiding your warranty with your cell phone provider or phone manufacturer. If all of your attempts at repairing your phone are unsuccessful, you will likely have no choice but to take it to your cell provider or to a place that repairs cell phones to get it fixed. Unless your phone is very valuable, the cost of repairing the phone might be higher than what you paid for it, and you might be better off buying a new one. It may be beneficial to purchase insurance from your cell phone provider to protect you from having to pay much, if anything, out of pocket to fix a water damaged cell phone.