If you are not using your household water outlets, there may be a problem in the public sewer main. Call the District’s 24-hour customer help line at 415-259-2949 to request service. If your household water outlets are being used, turn them off to stop the running water. This indicates a possible problem in your side sewer (lateral). You’ll need to call a plumbing company as the district is only responsible for public sewer pipes.
If the overflow is constant, remove the cap on the clean-out or overflow device (if available) located outside the building. Use towels, sheets, rags, etc. to keep the sewage from spreading and damaging other parts of the house.