• Sewer stoppage problems, business hours 7:30 am - 4:30 pm: (510) 537-0757
• After hours 4:30 pm - 7:30 am: (510) 506-5821
• For questions about repairs: (510) 537-0757

If you encounter a sewage overflow, in your home or property or in the public roadway, please immediately contact Castro Valley Sanitary District. Call (510) 537-0757 during business hours (7:30 am to 4:30 pm) or (510) 506-5821 after hours.

When you call, a technician will promptly come to the location of the reported overflow to determine if the overflow is located in the private sewer lateral or public mainline. The technician will clear the stoppage if the problem is in the mainline; otherwise, the technician will advise the caller the stoppage is not in the main and it is the responsibility of the owner of the private sewer lateral to clear the stoppage and relieve the overflow.

Sanitary Sewer emergencies are cases where a situation has been caused by some facility of the Sanitary Sewerage System. Those facilities include: private sewer laterals, sewer mainlines (usually located in the public roadways), sewer manholes, pump stations, and wastewater treatment plants.

Most sewer emergency calls received by the Castro Valley Sanitary District are for sewage overflows. Many sewage overflows are caused by blockages in the private sewer laterals (which are the responsibility of the property owner) or in the public sewer mainline (which is owned and maintained by the Castro Valley Sanitary District).

Overflows into your home could be evidence that a sewer backflow device may be required. Backflow devises are valves installed in the private sewer lateral which prevent sewage from "backing up" into your home. Backflow devises are required on all new homes and when a home is lower than the upstream public manhole, usually located in the street.

NOTE: If it is determined the stoppage was in the mainline after a resident has called a plumber the District is not liable for reimbursement to the resident for any work performed. Therefore, we highly recommend you contact the District prior to hiring a plumber to assess the situation.

For a "Report Sewer Problems" clip magnet for your home or office, please contact Pat at (510) 537-0757 or visit District offices (see address below).