San Mateo sewer lateral guideSelling a San Mateo home? Find out what your sewer lateral needs.
Answer a few questions to see whether the City likely requires an inspection, then get plain-language guidance on failed reports, repairs, replacement and City cost sharing.
Checked against City of San Mateo sources on
An independent guide
Not the City of San Mateo, and not a plumbing contractor. We explain the City's rules in plain language and link to the source for each one.
- Lateral starts at the building
- Cleanout
- Property line
- Under the sidewalk and street
- Wye connection
- Public sewer main
Where are you in the process?
Pick the situation closest to yours. Each path explains the rules that apply and the next decision to make.
- Selling a homeWhat the City expects before closing, and who handles the work if the lateral fails.Sellers, buyers and agents
- Need an inspectionWhether your situation calls for one, who can do it, and what the camera is looking for.Sale, remodel or overflow
- Failed inspectionRead the required work on your report and turn it into a plan, a set of quotes and a permit.Report in hand
- Repair or replacementSpot repairs, full replacement, permits, street work and the City cost-sharing program.Planning the work
Not sure where you fit? Tell us what's going on at the property.
Check whether you need an inspection
A few questions about the property and what's happening. You'll get a likely answer, the City rule behind it and your next step. Your answers stay in this browser tab.
Question 1
Already know you need one? Tell us about the property and your deadline.
What San Mateo requires
The property owner is responsible for the entire private sewer lateral, from the building to the public sewer main, including the wye connection to the main.
Events that trigger an inspection
- Selling a home
Selling a detached single-family or two-family home. The inspection happens before the sale.
Applies to: Detached one- and two-family homes
- Remodel or addition
A building permit for an addition or remodel of a detached one- or two-family home valued at about $90,000 or more. Confirm the exact threshold with the City.
Applies to: Detached one- and two-family homes
- Sewer overflow
A lateral backup that causes a sewer overflow at a commercial or multifamily building. Public Works decides whether an inspection is needed.
Applies to: Multifamily buildings, Commercial buildings
- Change of use
A change of use at an existing commercial building that raises its sewer customer class. The City sends a notice.
Applies to: Commercial buildings
Selling or remodeling soon? Tell us about the property and your deadline.
City cost sharing, FY 2026/27
For FY 2026/27 the City reimburses 50% of the lowest approved bid for a full lateral replacement, up to $2,500, while funding lasts.
Status: open. FY 2026/27 applications opened July 1, 2026 and are first-come, first-served until funding runs out.
- of the lowest approved bid is reimbursed
- 50%
- maximum reimbursement per property
- $2,500
- licensed contractor quotes, approved before work starts
- 3
- The program is not retroactive: work done before the City accepts the application and approves the quotes is not reimbursed.
- Any change to the approved scope or cost must be approved by the City before the work goes ahead, or the owner loses eligibility.
- The grant is taxable; recipients receive a 1099-G from the City.
Planning a full replacement? Start lining up your quotes early.
The City runs the program and takes applications. This site is not the application.
Get help with your sewer lateral
Tell us what you need and where the property is. A person reads every request and follows up about next steps.
- A person at Baysix Media reads every request.
- Your details go to a contractor only if you tick the referral box.
- The City does not recommend plumbers or contractors. Check any contractor's license before you hire.
Common questions
Short answers to the questions San Mateo property owners ask about laterals.
Checked against City of San Mateo sources on
Who is responsible for the sewer lateral in San Mateo?
The property owner is responsible for the entire private sewer lateral, from the building to the public sewer main, including the wye connection to the main.
This responsibility applies even where the lateral runs under the street (public right-of-way) or through a private easement.
The City does not repair, replace or clean private sewer laterals.
Do I need a sewer lateral inspection to sell my house?
An inspection is required when a detached single-family or two-family home served by a private lateral is sold, and it must be done before the sale.
If there is no inspection report and the seller does not provide one, the buyer must have a qualified plumbing contractor inspect the lateral and submit the report to the City before closing.
Does a condo or townhome need an inspection when it sells?
The City's regulations apply the sale and remodel requirements to detached single-family and two-family homes. If you own a condo, townhome or a building with three or more units, confirm with Public Works whether a requirement applies to you.
How long is a sewer lateral inspection good for?
No new inspection is needed if the lateral was inspected in the previous 5 years and that inspection found either no repairs needed, or only partial repairs that were then completed.
Does the City issue a certificate of compliance?
The City does not issue Certificates of Compliance. The sewer lateral inspection report serves as proof of compliance.
What happens if the inspection fails during a sale?
If a pre-sale inspection fails, the buyer and seller decide between them who handles the repair or replacement.
If the buyer takes on the repair, the work must meet City standards no later than 90 calendar days after the sale.
If the seller takes on the repair, it should be completed before the sale closes, or as otherwise arranged with the buyer.
Who can perform the inspection?
A licensed plumber or contractor must perform the inspection and complete the City inspection form. The City does not perform inspections.
The completed inspection form is emailed to San Mateo Public Works at lateral@cityofsanmateo.org.
Does cost sharing cover spot repairs or work I already paid for?
Not covered: spot repairs, partial replacements, pothole repairs, additional street resurfacing, CCTV inspection and root work.
The program is not retroactive: work done before the City accepts the application and approves the quotes is not reimbursed.
Still have a question about your lateral?
Tell us what's happening at the property and your timeline. A person reads every request.