Sonoma Valley County Sanitation District - Private Sewer Laterals

Lateral diagram

Sewer Laterals:

Sewer laterals are the pipes that lead from homes or businesses to the sewer main. Leaking private building laterals are often one of the main sources of inflow and infiltration, commonly referred to as "I and I," that is treated by the Sonoma Valley County Sanitation District (District) at its treatment facility.

I and I is usually a result of leaky or deteriorating laterals and sewer main lines, which allow groundwater and stormwater to seep into pipes, increasing the amount of water flowing to the wastewater treatment plant for treatment. Additional water from I and I increases the pumping and sewage treatment cost for the wastewater treatment plant.

It is the responsibility of the property owner to clean, maintain and replace their sewer lateral. Many of the sewer lateral pipes are old and are at risk for leaking raw sewage into the ground, causing plumbing problems in your home or business and contributing stormwater inflow to the sewer system during wet weather. Sewer laterals can be compromised by tree root intrusions, grease buildup, pipe cracks, and pipe sags.

As a result of a series of overflows between 2010 and 2014, the San Francisco Bay Regional Water Quality Control Board last year fined the District more than $700,000 and mandated the district to consider an ordinance that would result in sewer laterals being repaired or replaced. In order to prevent these costs from being passed on to residents, the District has passed an ordinance in a step to upgrade parts of the sewer that are known to be aging.

SVCSD Private Sewer Lateral Ordinance:

In response to the aging infrastructure, The Private Sewer Lateral Ordinance requires owners of property that are 30 years or older to have their sewer laterals inspected and repaired, if necessary, in order to prevent sewer overflows that contribute to pollution and result in costly fines to the District. An estimated two-thirds of the sewer laterals in Sonoma Valley are at least 30 years old and likely in need of repair.

In response to this issue, the District will be conducting video inspections and smoke testing of sewer laterals to property owners.

If you choose to decline this free inspection, you must notify the District by mail or by email at If the District does not receive notice of declining the inspection, the District will proceed with the free inspection. Property owners who decline this free inspection may be required to hire a qualified company that can produce a video/report in accordance with the National Association of Sewer Service Companies (NASSCO) Lateral Assessment and Certification Program (LACP), at the property owner’s expense.

Property owners will be notified only if their laterals require repair/replacement following completion of the inspections. Where significant defects are identified, property owners will have one year from the report date to complete any necessary repairs identified in the report.

Smoke Testing

The District will also conduct smoke testing in neighborhoods. The test identifies the sources of leaks and other problems in the sewer system, such as where storm water drainage is infiltrating the sewage pipes.  
Learn more about Smoke testing.

Lateral Rating Scale

Cracked Sewer Lateral PipeA rating of 1 to 3 means a properties sewer lateral is not failing but shows signs of damage that can cause issues in the future. Even though repairs are not required, we recommend you examine these issues and fix when possible. A letter of compliance will be issued by the District.

A rating of 4 or 5 means a properties sewer lateral is determined to be failing. The property owner will have one calendar year to make repairs using a qualified contractor.