CVSan is currently seeking public comment on a proposed Private Sewer Lateral Program.  This proposal would require all properties within CVSan’s boundaries that were built more than 20 years ago to have their sewer laterals inspected and repaired if necessary whenever the property is bought or sold.  The exception to this is if the property’s lateral was replaced less than 20 years ago.

Please review the Frequently Asked Questions below for more information and email Public Outreach Specialist, Natalie Croak, at to submit your comments about this program.  If you would like to review the complete program proposal, click here.  All comments that CVSan receives on the Private Sewer Lateral Program will be presented to the Board of Directors.


CVSan’s Proposed Private Sewer Lateral Program Frequently Asked Questions


1. What is a private sewer lateral?
A private sewer lateral (sewer lateral) is a pipe that connects a building’s plumbing system to the public sewer main (sewer main), which is typically located in the middle of the street. The sewer lateral begins at the junction with the building’s plumbing system, which is typically located within two feet of the building’s foundation wall, extends to the sewer main, and includes the connection to the sewer main.  The property owner is responsible for maintenance and repairs on the entire sewer lateral and the connection to the sewer main.

PSL Program_2018-03-27_0.jpg

2. What problems are associated with damaged sewer laterals?
The majority of properties in CVSan were built before 1960 and many still have their original sewer laterals.  Older sewer laterals can create problems for property owners because over time they deteriorate, leading to the pipe cracking, leaking, blocking, or breaking.  During wet weather, rain seeps into the soil and can enter the wastewater collection system (collection system) through damaged sewer laterals (infiltration); this can lead to more water flowing through the collection system during rainy weather than the system was designed to handle.  Sewer mains and the wastewater treatment plant can become overwhelmed by the amount of flow.  Click here for more information about sewer laterals from the Environmental Protection Agency (EPA).


CVSan’s wastewater is treated at the Castro Valley/Oro Loma Treatment Plant in San Lorenzo (above).

3. What is Inflow and Infiltration (I&I)?
Inflow is rainfall that enters the collection system through a direct connection, such as a downspout or an area drain that is connected to a sewer laterals. Direct connections to the collection system are illegal and CVSan requires that these connections are removed whenever they are found.

Infiltration is rainfall that enters the collection system from the soil surrounding an old or damaged sewer lateral.  During wet weather, rainfall accumulates as groundwater in sewer trenches and enters the collection system in higher levels than in dry weather.  CVSan is always looking for ways to reduce its I&I levels, and the Private Sewer Lateral program is designed to help reduce infiltration.

4. Why is reducing I&I so important?
High levels of I&I can cause sanitary sewer overflows (SSO) during wet weather.  An SSO is when untreated sewage flows out of the collection system before it reaches the wastewater treatment plant. 

High I&I levels can also cause unnecessary treatment costs because rainwater is unnecessarily treated when the flow reaches the wastewater treatment plant. This could raise the sewer service rates for all ratepayers if I&I is not mitigated.  High levels of I&I are a threat to public health, requires costly upgrades to the wastewater infrastructure, and has, at times, contaminated the San Francisco Bay.

5. Does I&I only come from sewer laterals?
I&I can enter the collection system through by the following means:

(a) Perforated manhole covers. CVSan does not have perforated manhole covers, aside from a small pick hole which is used by maintenance staff to insert a hook handle tool to lift the cover.  Manholes are in the highest point in the roadway and not in drainage channels. 

(b) Damaged sewer mains. CVSan owns and regularly maintains approximately 157 miles of sewer mains, and completes annual projects to reduce I&I that originates from damaged sewer mains.

(c) Direct connections to the collection system. Some Castro Valley homes may have improper direct connections to the collection system.  During a sewer lateral inspection, CVSan inspectors verify any direct connections to the collection system and notify the property owner to disconnect.

(d) Sewer laterals. CVSan estimates there are approximately 150 miles of sewer laterals within its boundaries.  CVSan does not own or maintain any sewer laterals.

6. Does the CVSan community have an I&I problem?
According to industry standards, CVSan has severe levels of I&I. Nationally, a typical Peak Wet Weather Flow (PWWF) to Average Daily Weather Flow (ADWF) ratio above 3.5 is considered high.  In the San Francisco Bay, collection systems with PWWF-to-ADWF ratios above five are common, and ratios above eight or nine are considered very high.  In CVSan’s 2006 Wastewater Collection System Master Plan, consultants found that CVSan has a PWWF-to-ADWF ratio of over 10 during the same design storm events (10-year, 24-hour storm).

West Yost RDII Graph-2018-03-05.PNG

7. What has CVSan done to reduce I&I?
CVSan proactively cleans, inspects, repairs, and replaces sewer mains on a routine basis.  Over the last two decades, CVSan has invested over $46 million in infrastructure improvements to reduce I&I.

125 RGB.jpg

Over the same period, CVSan allocated over $1 million to its Lateral Replacement Grant Program (LRGP).  LRGP provides available funds to property owners, or their agent, to defray a portion of the costs in replacing the sewer lateral, including the connection to the sewer main.  The maximum amount of assistance for any one sewer lateral replacement or repair is 50% of the lowest bid, up to a maximum reimbursement of $2,000.

045 Address Removed RGB.jpg
Above: A recipient from the 2016/17 cycle of LRGP

8. Will CVSan ever expand LRGP?
CVSan is considering increasing the funds allocated for LRGP in addition to implementing the Private Sewer Lateral Program.

9. Why is CVSan considering a Private Sewer Lateral Program now?
CVSan has been concerned about its I&I levels for the last two decades.  Though not an immediate threat, CVSan aims to proactively reduce its I&I levels and the number of SSOs.  CVSan is already working towards this goal by maintaining and monitoring its approximately 157 miles of sewer mains.  However, the sewer mains receive their flow from the approximately 150 miles of sewer laterals that are connected to CVSan’s collection system and are not currently maintained or monitored by CVSan.  Despite CVSan’s $46 million investment over the past twenty years into improving the wastewater infrastructure, CVSan has not seen a dramatic reduction of its I&I during wet weather.  This has led CVSan to conclude that a large portion of its I&I originates from sewer laterals.

Additionally, over the last decade, the EPA and the California Regional Water Quality Control Board (CRWQCB) have sued several San Francisco Bay Area (Bay Area) wastewater agencies to fix their damaged sewer pipes and reduce the SSOs that released hundreds of millions of gallons of raw or partially untreated sewage water in the San Francisco Bay.  To comply with the EPA’s mandate, these Bay Area wastewater agencies began Private Sewer Lateral Programs that require affected property owners to obtain a certificate of compliance certifying that their sewer laterals meet the required standards.  As a result, Private Sewer Lateral  Programs have become relatively common throughout the Bay Area.

ALCO agencies with PSL.PNG

CVSan has not been sued by the EPA or CRWQCB because the number of SSOs well below the California average.  CVSan strives to achieve a zero-tolerance for sewage spills, overflows, and other problems that pose a hazard to public health and the environment.  Click here for more information on CRWQCB’s Sanitary Sewer Overflow Reduction Program.

In addition, the Wet Weather Outfall and Nutrient Optimization Project with Oro Loma Sanitary District (OLSD) will require CVSan to reduce our wastewater flow into the wastewater treatment plant.  This will reduce CVSan’s allowable flow and will be costly if CVSan goes beyond the flow restriction.  Click here for more information on the Wet Weather Outfall and Nutrient Optimization Project with OLSD.

EBDA Flow Map2018-03-05.PNG

10. What types of properties would the Private Sewer Lateral Program apply to?
The proposed Private Sewer Lateral program applies to all residential, commercial, and industrial properties, including bank-owned properties.

11. When would a Castro Valley property owner be required to have a sewer lateral inspection?
A Sewer Lateral Certificate (SLC), or certificate of compliance, would be required whenever a property in CVSan’s boundaries is bought or sold.  To receive a SLC, the property owner or buyer would first need to hire a contractor to assess the condition of the lateral, typically through a closed-circuit televised (CCTV) video survey of the line, and obtain permits from CVSan.  CVSan will issue the SLC if the sewer lateral passes a verification test witnessed by a CVSan inspector.  Verification tests are typically a water or air pressure test that demonstrates that the sewer lateral can hold pressure over a certain period of time.  During the inspection of a sewer lateral repair, CVSan requires the sewer lateral to pass the verification test.

CVSan would recommend that the property owner, or buyer, to obtain at least three bids from a qualified plumbing contractor and be physically present to witness the CCTV video survey.

12. How long would the Sewer Lateral Certificate be valid?
If the property owner were required to completely replace the sewer lateral, the SLC would be valid for 20 years.  If the sewer lateral passed the verification test, or only required a repair, the SLC would be valid for 10 years.

13. Would the buyer or the seller be responsible for the sewer lateral compliance?
The current property owner is ultimately responsible for the sewer lateral compliance.  It is up to the buyer, the seller, and the real estate agent to negotiate this in escrow.  If the sewer lateral does not pass the verification test, then the current owner has the option to replace the sewer lateral to become compliant or provide the cost of the work to the buyer.  There is no requirement for the seller to have the compliance test performed.  The compliance is only triggered by the sale of the property.  A time-extension process is available if the buyer/seller negotiates to take on the sewer lateral compliance.  Since the housing market is currently a seller’s market, East Bay Municipal Utility District (EBMUD) has seen many buyers taking on the sewer lateral compliance.

14. What community outreach has CVSan performed, or is planning to perform, to educate the public about the Private Sewer Lateral Program?
CVSan first met with members of the Bay East Association of REALTORS (Bay East Realtors) in March 2017 to discuss the proposed Private Sewer Lateral Program.  The Bay East Realtors were notified that the program would be a discussion item at the March 6, 2018 regular Board of Directors (Board) meeting and were sent the program report prior to the meeting so they would have the opportunity to prepare comments and questions for the Board.  At the meeting, a draft version of the CVSan Code was presented to the public to serve as a framework to begin discussion about the Private Sewer Lateral Program.

CVSan plans to host future town hall meetings to address any concerns or questions from Castro Valley residents, property owners, and realtors. The next town hall meeting will be on Tuesday, April 24th from 6:00 - 8:00 p.m. at the Castro Valley Library. CVSan welcomes input on this proposed program at any time.  To submit your comments, email Public Outreach Specialist, Natalie Croak at