Keep a log of the amount of water indicated on the dipstick. An inch or two of water isn't the end of the world, because the tanks usually are inclined 5 degrees. The fuel pickup and return are located six inches from the bottom at the opposite end of the fill. More than two inches of water could cause a problem and need to be removed. Keeping regular entries of the accumulation of water, as indicated on the dipstick, keeps the problem in check.
Water usually comes from condensation, which can be prevented by keeping the tank full of fuel.
In warmer climates, bacteria and algae can grow in this watery environment, which can further foul your system. Don't forget your UPSs Most facilities that depend on generators have some kind of maintenance program in place to guarantee their reliability. It's shoved under a desk, behind a cabinet, in the bottom of a rack, and may live and die without anyone's knowledge. Having a routine inspection program for your UPS is just as important as having one for your generators. Depending on the sophistication of the UPS, operating parameters may be accessible.