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Redwood City, CA · Sewer Service, Laterals and Bay Flood Risk · ZIPs 94061 to 94065
Emergency Plumber in Redwood City, CA: City or County Sewer, and Where Your Lateral Ends
In Redwood City the sewer on your street may belong to the City or to San Mateo County, and the answer decides who you call at 2 a.m. The City owns part of the lateral too, from the cleanout to the main, which is more than most towns give you. This page covers that, the Bay flood risk, and the way we treat a call from outside our verified list.
City or County? How to tell who serves the sewer on your street
Redwood City serves the sewer for properties inside its Sewer Service Area on the City's map, which includes Redwood Shores. Properties outside that area are served by San Mateo County. The City's FAQ says your sewer bill names the agency, and notes that the City may supply your water without supplying your sewer.
- Inside the Sewer Service Area: call Public Works at (650) 780-7464 about an overflow or odor.
- Outside it: call San Mateo County at (650) 363-4100.
- After hours the City lists dispatch at 780-7190.
- Shut off water and central heating and cooling to limit a spill, keep sewage out of storm drains, and do not clean it yourself.
Sewage backing up? Call now and shut the water off while we talk.
Call (833) 840-2034The City owns the lower lateral: what that means for a repair
In Redwood City the City maintains the lower lateral, the section from the cleanout to the sewer main in the street. The owner is responsible for everything inside the property line, including the cleanout.
The cleanout is usually at the property line, about four inches across, under a steel or plastic cover, often in a round box about ten inches wide or a rectangular box ten by sixteen inches marked sewer. If none turns up, it may not exist or may be buried, and the owner must install it.
- Get the permit first for a cleanout. Request it, then hire the plumbing contractor.
- Ask for a City cleaning if the cleanout is at the property line. The City snakes from the cleanout to the main on request, and does not repair private-side lines.
- Pull the sewer repair permit. Lateral repair needs one from the Engineering and Construction Division at (650) 780-7380.
- Expect an inspection. A City engineer inspects the lateral to check it was done to code.
That order matters for a private-side sewer repair, because the City will not do the work and a missing permit holds up the final inspection.
A Bay-side city: flood maps, sandbags and what to ask
FEMA issued preliminary flood maps for Redwood City in August 2015, and the City's mapping layer shows a preliminary flood zone. Special flood hazard areas have a one percent annual chance of flooding. The City advises flood insurance for high-risk areas, because a homeowner policy does not cover flood damage.
- Look up your property in the City's mapping tool, or call (650) 780-7380.
- Sandbags are at 1400 Broadway.
- Report flooding, sewer spills and blocked storm drains to Public Works at (650) 780-7464.
- The City's pages do not describe a backwater valve, so ask a plumber whether a low drain or bathroom needs one.
After water has stood in a room, drying within a day or two matters more than the cleanup.
Water in Redwood City: what the regional report says
Redwood City Public Works supplies the water, and all of it is bought from the San Francisco Regional Water System, which draws on Hetch Hetchy. The City's own water quality page gave no hardness or pH figures, so the numbers below come from the system's 2025 regional report, not a Redwood City tap.
| Measure | 2025 figure | What it means at home |
|---|---|---|
| Hardness | 8.1 to 112 mg/L, average 62 | Soft, about 3.6 grains per gallon at the average (our conversion) |
| pH | 8.5 to 9.7, average 9.3 | Alkaline water |
| Disinfectant | Chloramination, highest running annual average 3.0 ppm | Fish and dialysis users need chloramine-rated treatment |
Water that soft rarely needs a softener. For water quality questions, Public Works answers at (650) 780-7464, and the City posts blend change notices on its water quality page.
Which counter issues which permit in Redwood City
The Building Division and Permit Center is at 1017 Middlefield Road, (650) 780-7350, and applications go through an online portal. The City's building FAQ says a permit is required for all work not exempt under the building code, and it does not name water heaters or repiping.
That is why we say to confirm before ordering a unit. Sewer lateral permits are a different counter, the Engineering and Construction Division at (650) 780-7380, not the Building Division.
A drain that keeps clogging and a leaking tank in Redwood City
| Symptom | Page |
|---|---|
| A drain that clogs again and again | Drain cleaning and jetting |
| A concealed leak, or a rising bill | Tracing the leak |
| Lukewarm water, or a leaking tank | Water heater repair |
| A split or burst pipe | Stopping a burst pipe |
How we answer a Redwood City call
Redwood City's ZIP codes, 94061 to 94065, are absent from the list we verify against. For that reason the city is not offered as covered.
Call us with the street address. If we cannot send someone you learn it on that call and can phone a closer plumber at once.
Not sure we reach your street in Redwood City? Call and ask.
Call (833) 840-2034City or County sewer, lateral permits and hard water in Redwood City
Do you serve Redwood City?
Redwood City's ZIP codes, 94061 to 94065, are absent from the list we verify against, so Redwood City is not offered as covered. Call with an address and we say whether we can come.
Who owns the sewer lateral at a Redwood City house?
The City maintains the lower lateral from the cleanout to the main. The owner is responsible for everything inside the property line, including the cleanout.
Does a sewer lateral repair in Redwood City need a permit?
Yes. The City's sewer FAQ says a permit is required and that a City engineer inspects. Permits come from the Engineering and Construction Division at (650) 780-7380.
Does the City or the County serve my sewer?
Check your sewer bill, or the City's Sewer Service Area map. Inside the area the City serves it, and outside San Mateo County does.
Is the water in Redwood City hard?
The regional system's 2025 report shows an average of 62 mg/L, which is soft, with a pH average of 9.3. That is a regional figure, not a Redwood City tap measurement.
Wondering if we can send someone to Redwood City?
Call us with the street address. A direct answer on a visit comes first, and no work begins before a written range.