Removing water from gas can be accomplished using chemical additives or by using filters and/or funnels. For e10 gasoline (with ethanol), adding high-octane fuel and running the contaminated gas through the engine separates the water.
To remove water from gas safely, use a chemical additive such as HEET that contains methanol and other additives that bind with the water to make it sink to the bottom of the gas tank. The additive also absorbs water to keep it from blocking the fuel line and then burns up as it passes through the hot engine.
Another safe cleaning method is to pour the contaminated gas through a special filtration device, such as a Mr. Funnel, designed to trap water and other debris in a sump. The contaminated gas runs through the funnel while the water is collected in the sump. The filtered gas is then collected in the gas tank or other receptacle.
Drivers who use e10 gasoline potentially face more problems with water because ethanol actually absorbs water. According to “Removing Water from E10 Gasoline,” with less than half a tank, you can safely run the contaminated gas through the engine by filling the tank with high octane (91-93 or higher) and running the tank empty as quickly as possible.