San Mateo's homes
By Census estimates, about 103,105 people live in San Mateo,2 and the city has about 42,641 housing units, with about 39,895 occupied.2 Detached houses make up about 42 percent of San Mateo's housing units and attached houses about 10 percent;3 buildings with five or more units account for about 42 percent, and buildings of 50 or more for about 17 percent.
Census estimates put San Mateo's median year built at about 1965;4 the 1950s are the largest decade at about 21 percent of units, and units from 2000 or later are about 13 percent.4 About 30 percent of San Mateo's housing units have two bedrooms and about 28 percent have three;5 about 28 percent are studios or one-bedroom homes.
Renters and households in San Mateo
About 64 percent of San Mateo's renter households live in buildings of five or more units,6 Census estimates show, while about 17 percent are in a detached house; about 3,477 owner households live in buildings that size. Among San Mateo's renter households, about 9,474, or about 47 percent, date their move-in to 2020 or later,7 while the owner share is about 13 percent.
Owner homes in San Mateo hold about 2.57 people on average and rented homes about 2.51, about 2.54 overall,8 Census estimates show. About 30 percent of households include someone 65 or older,8 about 29 percent are one person living alone8 and about 28 percent include someone under 18.8
San Mateo's carts
The City of San Mateo says one company provides garbage, recycling and organic collection for all City residents.9 Under an ordinance adopted November 19, 2018, San Mateo residential waste containers must be at the curb after noon the day before service and retrieved by midnight the day of service.10 Carts go with the wheels against the curb and the lid's arrows pointing toward the street, the City of San Mateo says,9 with about 24 inches between each cart.
The green, blue and black carts in San Mateo
San Mateo's green cart takes food scraps and soiled paper with yard trimmings, the City says,10 including coffee grounds, tea bags, egg shells, pizza boxes, paper plates, napkins and cups. Anything that does not go in the recycle or compost carts in San Mateo goes in the black cart,10 and the City says everything placed there goes directly into the landfill.
San Mateo's blue cart is single-stream with no sorting, the City says:10 newspaper, junk mail, magazines, office paper, milk and juice cartons and cardboard go in with plastic, aluminum and glass containers. State rules require everyone in California to recycle all organic waste,11 including paper, cardboard, yard materials, food scraps and food-soiled paper, the City of San Mateo says.
Renting in San Mateo
For residents of multifamily dwellings in San Mateo, including apartments, condos and townhomes, the City says building management is required to provide organics collection service, education and outreach.11 The City Council adopted a Residential Tenant Protection Program on December 1, 2025, adding Chapter 10.100 to the Municipal Code, the City of San Mateo says.12 The City's resource page lists a helpline for tenants and landlords throughout San Mateo County12 that gives information on all types of tenant-landlord issues and offers dispute resolution options.
Bulky items and household hazardous waste in San Mateo
RethinkWaste's service guide says residential customers receive two curbside bulky item appointments per calendar year,13 on the regular collection day, Monday through Friday, from February 1 through December 31.
The City of San Mateo says residents can schedule an appointment to dispose of household hazardous waste through the County's program, whose collection facility is in the City of San Mateo and opens every Thursday, Friday and Saturday, except major holiday weekends.14 San Mateo's household hazardous waste page lists paints, automobile fluids, pesticides, poisons and cleaning chemicals.14 RethinkWaste's public recycling center takes select household hazardous waste items as a drop-off from residents only,15 RethinkWaste says.
Drains in San Mateo
The City of San Mateo says storm drains, or outdoor drainage, typically flow to the nearest creek or watercourse,16 while indoor drains connect to sanitary sewer lines that flow to the City's wastewater treatment plant. The City of San Mateo's best management practices page encourages residents to practice pollution prevention in household activities.17 Marina Lagoon is a remnant of a tidal slough, diked and dredged, about 4.5 miles long,18 that now helps protect the city from flooding, the City of San Mateo says.
Tap water in San Mateo
California Water Service says water for its San Mateo system's customers is purchased from the San Francisco Public Utilities Commission,19 per its 2025 report. That 2025 report shows an average hardness of 62 ppm for the system,19 and the company calls water soft below 75 ppm under its own scale. California Water Service's Drought FAQs list, among restrictions for its customers, that water cannot be used to clean driveways or sidewalks.20
San Mateo's rain and smoke record
NOAA's San Mateo 0.8 NE station averages 19.30 inches of precipitation a year, per 1991-2020 normals.21
A November 16, 2018 entry in NOAA's Storm Events Database notes wildfire smoke prompting school closures in San Mateo,22 part of smoke from the Camp Fire that lasted until November 21 in the region.