When you have poured in the water and the fuel, don't forget to shake the contents (so that the water can pick up the ethanol) thoroughly before allowing the water/ethanol mix to separate.

On a larger scale this method might be used to remove the ethanol from the fuel; Take a jerrycan and add a spigot to one of the sides close to the bottom. Fill the jerrycan 80% with fuel. Add 10% water and shake. Then allow the water/alcohol mix to settle on the bottom. Use the spigot to drain all the water. You should now have fuel with a lot less alcohol in it.

The problem of course is what to do with the remaining water/ethanol mix. It might very well be contaminated with methanol (on purpose).

Roland --- Yeah, I noticed Mark put in the before-shaking picture instead of the post-shaking picture. Now we're trying to figure out what to do with 110 mL of watery gas....

Just pour it on the ground. Way too much is made of petroleum "contamination." It's ORGANIC. The soil bacteria will take care of any hydrocarbon that is not readily volatolized into the air.

"Decontaminating" soil that has been exposed to leaking oil/fuel tanks is a giant scam. They excavate the area and carry away the soil. (Where do they put that? Isn't the dump site then contaminated too and just as liable to spoil the ground water?)

And then they plant a pipe that supposedly allows the remaining petroleum product to volatolize to the atmosphere. Yea, right.

The treatment for a patient who ingests straight gasoline? Nothing. It'll give you diarrhea for a while. Just don't vomit while your stomach is full of it-- if you inhale it, it could cause lipoid pneumonia.

The concentration of a liquid pored into the ground will diminish by the distance cubed from the source: you won't be able to measure the product even a few feet from ground zero after a while.

Every chance I got on a recent trip out west I got Ethanol free gas, but in most cases it came from the same hose as the Ethanol gas. In the case of the shared hose wouldn't the first gallon have the 10% ethanol if the previous driver filled up with it? Does your local station have a separate hose? If not do you put some in the truck first?

@doc: Interesting! I hadn't thought about that, but it makes sense.

Anna: there is actually evidence to support that. See e.g. Biodegradation of hydrocarbons in the environment or Oil degradation in soil.

Ok, so an (Amazon Associate paid link to a) graduate cylinder, and what I assume is fuel. But no details on what test you're doing, how you're doing it, or how to interpret the results. Let me rush right out to click your link, buy the cylinder, and pour some gas into it. Not that I'd know what the hell anything meant, but hey, you'd make a dime, right?

After performing a test for ethanol in your gasoline, you will have about 110ml of water contaminated gas. To safely and responsibly dispose of it, pour it into your truck. The 10ml of water will be easily diluted with the 10-20 gallons of fuel already in the truck and you'll never notice the difference in performance. The only concern might be if you were very low on gas and the temperatures were well below freezing, the water might form ice in the tank or fuel lines. As long as you do this in warm weather on a mostly full tank of fuel, it will be fine.