Dirty water

 is the most common water in the game, and can be found in the lakes and rivers of Fallout 3. Unlike Purified Water, this will give you radiation, which can be cured for a fee by your local friendly doctor, by using Rad Away, or by using your infirmary.

Dirty water differs in appearance from purified water. Dirty water is labeled "WATER", while purified water is labeled "H²O"; the bottle is also grimier. The Pip-Boy icon for both is the same, however.

Glitch: Xbox 360-no health is gained from water and you get +5 rads. This only affects one of my three save files and is not that big of an issue.