If you are a biker or runner, there are now special filtering water bottles to remove impurities, cysts, bad flavor, etc. They fit most bottle holders. Update Bulletin No. The newer gasoline formulas do get old, in as little as one month, and mowers will not run or run rough on it. You should add a fuel stabilizer to the gasoline if it will not be used for a while.
Stabilizers can keep gasoline fresh longer than a year.
Nontoxic powder stabilizers, like Tecumseh's Ultra-Fresh, are safest and easiest to use.