Water that smells like rotten eggs typically contains hydrogen sulfide gas or sulfur bacteria, both of which are safe to drink. However, if the rotten egg smell stems from sewage or other pollution, it may be unsafe for consumption.
While water containing hydrogen sulfide is safe to use, it causes corrosion to metal piping and discolors copper and brass utensils. Additionally, sulfur creates a slime that clogs plumbing and acts as a breeding ground for iron bacteria. Hydrogen sulfide gas does become harmful once it enters the air, so it is important to eliminate its source before it causes problems.