San Mateo County · San Mateo, CA
Plumbers in San Mateo, CA
San Mateo is in San Mateo County, California. About 141,000 people live in the 5 ZIP codes we cover here, in roughly 57,000 homes, 41% of them single-family detached houses. The biggest share of the housing was built between 1960 and 1979 (36%), and that age decides most of what goes wrong with the plumbing.
- Same-day service when a plumber is available
- 5 ZIP codes covered
ZIP codes we cover in San Mateo
94401, 94402, 94403, 94404, 94497
San Mateo homes and their plumbing
Here is how San Mateo's homes break down by year built, based on Census estimates for the covered ZIP codes: before 1940 7%, 1940–1959 28%, 1960–1979 36%, 1980–1999 18%, 2000 or later 11%. With that many older homes, original galvanized supply pipe and cast iron or clay drains are still common, so leaks, rust and root intrusion come up often. Neighboring areas such as Redwood City are covered too.
| Year built | Share of homes |
|---|---|
| Before 1940 | 7% |
| 1940–1959 | 28% |
| 1960–1979 | 36% |
| 1980–1999 | 18% |
| 2000 or later | 11% |
Share of housing units in the covered ZIP codes. Census ACS 2023 5-year estimates.
- Residents in covered ZIPs
- 140,535
- Housing units
- 57,269
- Single-family detached
- 41%
- Owner-occupied
- 52%
- Heated with utility gas
- 56%
- Heated with electricity
- 39%
What goes wrong in San Mateo homes
1960s and 70s homes reaching end of life
36% of the housing here dates from 1960 to 1979. Original copper supply lines in those homes are now 45 to 65 years old, and cast iron drains of that age scale up inside and crack. Seized shutoff valves, pinhole leaks and recurring main-line clogs are common calls. A camera inspection shows the condition of the sewer line before anyone digs.
Pre-1960 homes: galvanized pipe and cast iron
35% of homes in San Mateo's covered ZIP codes were built before 1960. Houses that old often still have galvanized steel supply lines that rust closed from the inside, and cast iron or clay sewer pipe that cracks and lets roots in. Weak pressure at upstairs fixtures, brown water after a shutoff and slow drains are the usual clues. Typical fixes are whole-house repiping and a sewer camera inspection.
Natural gas in most homes
56% of occupied homes here heat with utility gas, so gas water heaters, ranges and dryers are common. That means gas line extensions for new appliances, flexible connector replacements and venting checks when a water heater is swapped. If you smell gas, leave first and call the gas utility from outside. See gas line repair.
Apartments, condos and attached homes
Only 41% of homes here are single-family detached houses. In attached buildings a leak or clog often involves a shared stack or a neighbor's unit, so it's worth knowing which lines are yours and which belong to the building or HOA, and where your unit's own shutoff is.
Common calls in San Mateo
- Sewer Camera Inspection
- Whole-House Repiping
- Gas Line Repair
- Drain Cleaning
- Water Heater Replacement
- Main Water Line Repair
- Sewer Line Repair
Also available in San Mateo: emergency plumbing and every plumbing service.
San Mateo at a glance
- County
- San Mateo County
- ZIP codes
- 94401, 94402, 94403, 94404, 94497
San Mateo plumbing FAQ
How old are the homes in San Mateo?
In the ZIP codes we cover around San Mateo, Census estimates put 35% of homes as built before 1960, 36% from 1960 to 1979, 18% from 1980 to 1999 and 11% in 2000 or later. The largest group is 1960–1979 (36%).
Who licenses plumbers in San Mateo, CA?
The Contractors State License Board (CSLB) licenses plumbing contractors under the C-36 classification, and its online lookup shows license status.
Are water heaters in San Mateo usually gas or electric?
Census data for the area show 56% of homes heating with utility gas, 39% with electricity. Water heaters often use the same fuel as the home's heat, so utility gas is the most common here, but check the label on your tank before you shop for a replacement.
Guides for San Mateo homeowners
Nearby areas
Also covered nearby: Belmont (3 mi), Burlingame (4 mi), San Carlos (4 mi), Millbrae (6 mi), San Bruno (8 mi), El Granada (9 mi), Half Moon Bay (9 mi), Atherton (9 mi).
Housing, heating and population figures are US Census Bureau American Community Survey 2023 5-year estimates for the ZIP code areas we cover in San Mateo, so they may include neighboring communities that share those ZIP codes.
Need a plumber in San Mateo?
Same-day service when a plumber is available. One call connects you with a licensed plumber who serves your ZIP.