I was getting premium non-ethanol from a brand-name station and still had to have my car's (fairly new w/12,000K miles) gas tank drained due to water contaminated gas. The guys at the dealership didn't want to do anything, but suggest a gas anti-freeze at first because they have to follow EPA procedures when draining the gas, etc.. I've switched gas stations, but found on the internet this contamination thing is more prevalent than I thought and it's virtually impossible to get the suspect gas station to pay the repair expense!

I think nowdays when almost all gas stations are "convenience stores" rather than "service stations" they either don't check or are pinching penneys too much to care to pump the water out of their tanks.

Back when I was fresh out of high school I pumped gas at a Philips 66 station right off the interstate, we had to measure the fuel tanks with the stick at the end of shift and used some stuff that came in a tube to smear the first 6" of the stick, if there was water it would turn bright green. Once the tank had "x" inches of water it would be pumped out. Of course that was 1972 when regular was 29.9/gal and Hi-test was 30.9/gal, we cleaned the windshield, asked if they wanted the oil and trans fluids checked and topped up the windshield washer fluid and checked tire pressure. Gawd this sounds like an old Texaco ad, "Trust your car to the man who wears the star"

I try to follow a few simple rules, if there is a tanker delivering fuel, drive on by. Dropping 3000 or 6000 gallons stirs ups all the water and sludge in the underground tank. If your around town find a good station and stick to it, there is allways a good reason someone is undercutting the price, not much you can do if traveling.

Gas line anti-freeze is nothing more than alcohol, alcohol "likes" water so adding it to your tank will absorb some water and mix with the alcohol so your car does not gulp pure H2O.

Today with the EPA all over everyone, I can imagine the cost to dispose of water pumped out of a storage tank. I am almost sure back in 72' the pumped water was probably dumped off down in the Meadowlands off of NJ Rt 3. I can only imagine it being sealed in double lined drums and buried in Utah today.

I also heard the ethanol-blend (10%) messes up O2 sensors.

A high volume Gas station. Try to make your purchases from just one Gas Station if possible, This practice will eliminate any other source of contamination if the gasoline is suspect and you are insured a product that was recently distilled from the distribution terminal.
All Gasoline (Petrol) contains small quantities of water, It is not an anhydrous compound, Hygroscopic in that it has a great affinity to absorb moisture. Gasoline typically contains 100-150 PPM water, Beyond that, Problems with an internal combustion engine will manifest, Not really a great concern since you are not flying an airplane.
Adding 8 oz of a 50/50 mixture of Isopropyl Alcohol/Toluene to a full tank of gasoline every 3/5k miles will help eliminate moisture in the fuel system and clean the injectors/Carburetor, Nothing else is needed.
Ethyl Alcohol with prolonged exposure to plastic fuel system components will compromise their integrity, This is especially true with early models. I am unsure of the effects it has on Oxygen sensors.

HTH

ATB Mike

two different people I know who own 02 chevy trucks have had to change their fuel filters because of the "black goo" that stops them up.
And one of these fellows had just replaced his filter less than a year before.
They were both told that it had something to do with the ethanol in the fuel.
Ray