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Frequently Asked Questions

1. Sewage is backing up into my house/building through overflowing toilets, sinks, bathtubs, dishwashers, and/or washing machines. What should I do? 

A. CALL US FIRST. Contact West Bay Sanitary District (WBSD) immediately to report a sewage overflow. Call (650) 321-0384, 24 hours a day, seven days a week.

B. If these problems occur and you are not using your household water outlets, there may be a problem in the public main. Call (650) 321-0384 to request service.

C. If your household water outlets are being used, turn them off to stop the running water. This indicates a possible problem in your sewer lateral. You need to call a plumbing company (located in the yellow pages of the phone book) since WBSD is only responsible for sewers not on private property.

D. If overflow is constant, the homeowner should remove the cap on the cleanout or overflow protection device (if present) located outside the building. The homeowner can use towels, sheets, rags, etc. to keep the sewage from spreading and damaging other parts of the house.

2. What will the District do when a backup occurs? 

WBSD will assess the backup to determine if the blockage is in the public sewer mainline or the property owner’s private sewer lateral. The District may provide sewer lateral/side sewer clearance, between the public sewer and the property line provided that the sewer lateral and the property line cleanout conform to the requirements of the Districts Code of General Regulations Section 401 Building Sewers & Connections.Property owners are responsible for blockages that occur in their private sewer lateral, from the building and extending to the connection to the public sewer mainline. Notwithstanding the provision of these clearing services, the District will have no responsibility for costs incurred by a property owner that privately contracts for sewer clearing services Section 401.08 Side Sewer Clearing. [Gen. Reg. 111]If it is determined that the public sewer mainline is blocked, only WBSD has the authority to clear the system. If the public sewer mainline is clear, the District’s representative may advise the property owner to contact a plumbing contractor to perform maintenance to their private sewer lateral.

3. What is a sanitary sewer collection system? 

A collection system is a network of pipes, manholes, clean-outs, lift stations and other structures used to collect all wastewater and transport it to a treatment plant or disposal system. WBSD is a collection system only.See the list of “dos and don’ts” on our web site regarding what food waste should be put through the garbage disposal

4. Where is WBSD sewage treated? 

Treatment and disposal takes place at the Silicon Valley Clean Water (SVCW) Wastewater Treatment Facility in Redwood City. SVCW is jointly owned by and serves WBSD and the cities of Redwood City, San Carlos and Belmont. The treated clean water from SVCW is ultimately recycled in one of two ways. A small amount of the treated water is returned through special pipes (within Redwood City) to irrigate plants on public streets. The bulk of the water is discharged in deep-water outlets in San Francisco Bay.

5. What is a Sewer Service Charge? 

The purpose of the sewer service charge is to raise revenue for the cost and maintenance and operation and for renewal and replacement of the facilities necessary to collect, treat and dispose of wastewater generated from your home or business. To see residential rates click here.

6. How do I pay my Sewer Service Charge? 

The District uses the San Mateo County Tax Rolls as the primary method of collection of the Sanitary Sewer Service Charge on an annual basis. This line item shows up on the property owner’s property tax bill under the Special Assessments section. On special circumstances the District will manually bill property owners. To see rates click here.

7. How does my rate compare to other sewer service charge rates in the area? 

The District has competitive rates in the counties surrounding the San Francisco Bay and lower than the average annual charged in the State of California.

8. What is the purpose of manhole lids? 

The manholes circular metal lid usually located in the middle (sometimes to the side) of the roadway are for access to the sanitary sewer pipe. Only authorized District personnel can remove the manhole. Unauthorized entry into manholes is extremely dangerous and strictly prohibited.

9. If I notice missing, damaged or noisy manhole lids (loose fitting) what do I do? 

Please report it to the District immediately by calling (650) 321-0384, 24 hours, 7 days a week.

10. What causes a sanitary sewer to backup? 

Most sewer backups happen because the line is plugged with an obstruction. However, backups can be caused by several factors including the condition of the sanitary sewer system itself, natural phenomena such as earth movement, heavy rainfall, and the incorrect usage of the system by the public.

Some common backup causes are:

  • Solids / debris: Typical solids that buildup in the pipe and cause backups are dirt, hair, bones, feminine products, non-flushable wipes, paper towels, kitty litter, diapers, broken dishware, garbage, concrete, and debris.
  • Fat/Oil/Grease (FOG): When FOG is discharged into a sewer system they will solidify and, after a while, can build up and plug drain lines in your home, building, or complex. Solids and Debris can also plug the sewer lines owned by the District, thus increasing the maintenance cost to the District. Plugged sewers can also cause flooding of nearby private homes and businesses.
  • Tree Root infiltratio: Tree roots can cause backups. Roots can infiltrate the pipe system and block the wastewater flow.
  • Water inflow/infiltration: Rainwater entering the public sewer line can cause system problems and overflows.
  • Illegal connections: roof gutters and storm water runoff discharged to the sewer system by pumps or gravity take up system capacity which was designed for the transport of wastewater only.
  • The discharging of swimming pool water to the sanitary sewer in excess of required flow rates to prevent overflow conditions and without a permit.
  • Illegal dumping-accessing the system without permit or permission to dispose of waste not intended for the sanitary sewer system. This type of activity is against the law. If you witness this type of offense, obtain a description of the perpetrator and vehicle license and call the District at 650-321-0384. 
  • Structural defects in pipes and manholes: Significant sags, bellies in the line, cracks, holes, protruding laterals, misaligned pipe, offset and open joints and collapsing pipe material are all possible causes of backups.
11. What is the Annexation process? 

For property outside of the District’s service area the following will need to occur before sanitary sewer service to the property can be established. The parcel will need to be annexed into the West Bay Sanitary District (WBSD) service area. To begin this process, the applicant or the property owner would have to annex the property into the West Bay Sanitary District through the San Mateo Local Agency Formation Commission (LAFCo). As part of the application, the applicant will need to hire a civil engineer to prepare the map and legal description of the parcel as prescribed by State Board of Equalization requirements, and to design the sewer system; comply with the requirements for an environmental review per the California Environmental Quality Act (CEQA) regulations; and pay processing fees for the annexation set by LAFCo and WBSD.

12. What is an Easement? 

An Easement is an interest in land owned the property owner that entitles its holder (WBSD) specific limited use. This document is usually recorded in the office of the San Mateo County Recorder. A sanitary sewer easement creates a non-exclusive, perpetual right to use a portion of your property for sanitary sewer purposes. This provides the District with access rights to repair, replace, inspect, enlarge, change, maintain, test and/or remove the sanitary sewer located within the easement. Please click here for more info on Easement.

13. Who can enter my property? 

The District, if it has an easement, may go onto the easement at any time. The District may, on occasion, have a Contractor present to perform specific tasks relating to the District’s operations. We will make an effort to notify you prior to entry, however, in the case of an emergency we may need to enter without prior notification. Please request, at any time, to see District personnel photo identification cards, or contact the District at (650) 321-0384.

For Commercial Businesses: The District Manager and other duly authorized employees of the District bearing proper credentials and identification shall be permitted to enter upon all properties for the purpose of inspection, observation, measurement, sampling, and testing in accordance with the provisions of the District's Code of General Regulations, if the property has an easement, WBSD personnel may go onto the easement at any time. The District may, on occasion, have a Contractor present to perform specific tasks relating to the District’s operations. We will make an effort to notify you prior to entry, however, in the case of an emergency we may need to enter without prior notification. Please request, at any time, to see District personnel photo identification cards, or contact the District at (650) 321-0384.

14. What is an encroachment on an easement? 

An encroachment is a physical intrusion in an area of the easement contrary to the agreement. The District may require that any unauthorized encroachments be removed at the property owner’s expense. All encroachments on easements require written approval of the District by way of a variance from the District’s General Code of Regulations.

15. Are there penalties for locating structures or improvements on an easement? 

The property owner may be faced with all costs of removal and any associated damages resulting from unauthorized structures or improvements on land subject to an easement.

16. I have slow drainage through my toilets, showers, and sinks. What can I do about it? 

If neighbors are having similar slow drainage, there is a chance that there is a problem in the public main. For service call (650) 321-0384.

If neighbors are not having a problem the problem may be within the plumbing of your house / building or the lateral line leading from your house / building to the main sewer line. You may need to call a plumbing company (yellow pages of phone book), but call us first and let us help determine the nature of the problem at (650) 321-0384.

17. My sewer lateral or sewer main was broken by a contractor or utility. What should I do? 

The District repairs broken sewer lateral connections to mains and sewer mains that are broken by private contractors or utilities (PG&E, Cal Water, cities, etc). While the contractor or utility is responsible for notifying the District immediately, residents can call (650) 321-0384 to report such an incident or to confirm a report has been made.

18. There is a manhole cover in my neighborhood that rattles and continues to irritate me every time a vehicle rolls over it. What can I do about it? 

The District has two main types of sewer structures: 1) a manhole that varies in size from 25″ to 42″ in diameter, and 2) a rodding inlet, which is round or oval and ranges in size from 9″ to 18.” Both structures have solid covers and are normally imprinted on top with “WBSD” or “Sanitary Sewer”. Occasionally, there may be a separation between the base and the cover of the manhole or rodding inlet causing the cover to rattle when a vehicle rolls over it. To report a rattling manhole or rodding inlet cover, call (650) 321-0384.

19. What can I do about sewer odors? 

First, try to determine where the odor is coming from inside the home or outside. If an odor is coming from inside the home, there may be a problem with the internal plumbing system. Check your internal system first or call a plumbing company. If the problem exists outdoors, other possible causes could be decaying leaves in storm drainage catch basins (notify city or county personnel), PG&E gas services and mains (notify PG&E), and for sanitary sewer call WBSD at (650) 321-0384.

20. I paid a plumber to repair my side sewer. It turns out the problem was occurring in the public sewer. Can I be reimbursed for my plumbing bill? 

Possibly. Of course we would like you to call us first at 321-0384. You may be partly reimbursed if you are new to the area and have called a plumber prior to calling WBSD, and it turns out that the cause of the problem was a stoppage in the publicly owned sewer. In these instances, the District may reimburse the homeowner for a portion of the cost of the plumber or drain service. To obtain reimbursement, follow these simple steps:

  1. Call the District office and request a Claim Form,
  2. Provide the required information on the claim form outlining the circumstances and enclose a copy of the paid invoice from the plumber or drain service.
  3. Mail the Claim Form to: West Bay Sanitary District Attn: Regulatory Compliance Coordinator 500 Laurel Street, Menlo Park, CA 94025
  4. Upon investigation and approval, the homeowner may be reimbursed, covering up to one hour of reasonable charges by the plumber or drain service or the claim may be denied. For property damage claim information, or if you have any questions, please contact WBSD’s Regulatory Compliance Coordinator at (650) 321-0384 or