Water can enter your vehicle's gas tank in various ways, such as if you leave the gas cap off during rainy weather or if you frequently drive your car with the gas tank less than half full. There are several symptoms that will indicate if there is water in your vehicle's gas tank.
Water dilutes gas and if water is in your gas tank you may need to fill your vehicle up with gas more often than usual.
Your vehicle may jerk or hesitate when you press the accelerator. You may notice that it does not accelerate properly or suddenly decreases speed while you are driving.
Your car may not start at all. It may seem that you are out of gas. Your vehicle may try to idle and then immediately shut off.
Fuel System Damage
Water is heavier than gasoline, so it will stay at the bottom of your gas tank. Most vehicles do not pump gas from the very bottom of the tank into the fuel system, but if the tank is nearly empty the vehicle may pull in the water. Accordingly the water on the bottom of the tank will be transferred through pipes and hoses causing damage and rust over time.