When experiencing a rotten egg type odor at the tap, the first step is to attempt to isolate the source of the odor.

First, check to see if the odor is present at all taps or just one. If the odor is present at only one tap, the source of the water is most likely the drain in that particular sink, shower or bath tub. All of the plumbing fixtures in your home receive their water from the same source, therefore if the water is the source of the odor, it would be present at all the taps. If you detect the odor at only one tap, the likely cause is within the drain.

If your sink or shower is clogged or drains slowly, use a commercial drain opening product to eliminate any blockages. If your sink is not clogged, simply flush the drain of the fixture with about a half cup of bleach. (Do not use BOTH commercial drain openers and bleach as this may cause a hazardous reaction.) Often food particles, hair and other items build up in the drains, causing the odor. To prevent these odors from returning, routinely flush all drains with a half cup of bleach once a month.

If you detect the same odor from all faucets, the next step is to run some water into a glass and take the glass into another room where there is no plumbing, such as the living room. Is the odor still present?

If the odor is no longer present, the source of the odor is within the drains. See the recommendations above regarding flushing drains to prevent odors.

If the odor can still be detected when you are not near any drains, determine if the odor is coming from the hot water only, or cold only or both hot and cold: Hot or Cold or Both

Water Quality Decision Tree