Coastal water I hear they drink it down south.

Adding alcohol does not degrade gas if it has water in it, it in fact
increases octane and it is common in the midwest to be 10% alcohol from
the pump. Pure alcohol can absorbe something like 10% water and not have
a volume increase of the alcohol. Alcohol is harder to start on and less
power , but absorbes water alowing it to be burned. For a car that
nocks besause it needs higher octane you have 2 choises retard timing or
add alcohol . But just hard starting could be 20 different car problems
and not bad gas.