The smell is being blamed on too much of a good thing. The culprit is water conservation.
The Public Utilities Commission says that customers have been cutting down on their aqua use, leaving the sewage waste less diluted and more like sludge.
Hence the rotten egg smell.
Water usage is down for a variety of reasons.
The commission has been able convince more customers to convert to low flow toilets.
The down economy is also forcing people to pull back.
And this winter's wet weather has eliminated some of the demand.
To combat the smell, the PUC will spend roughly an additional $2 million over the next few years on bleach.
The PUC said they have no regrets. They told NBC Bay Area that the city of San Francisco has cut its annual water usage by 20 million gallons.