San Francisco County · San Francisco–Oakland–Fremont metro
Plumbing help in San Francisco, CA
Older PipesFrozen Pipes
San Francisco's plumbing is old: three in four homes predate 1980, and the median home was built in the 1940s. Its Hetch Hetchy water is exceptionally clean, so the city's plumbing problems come from age, such as galvanized supply lines, cast iron drains and old sewer laterals, rather than from scale.
- Median home built
- 1946
- Built before 1980
- 75%
- Owner-occupied
- 37%
- Water hardness
- See below
- Winter
- Hard freezes are rare
- Plumbing code
- Local
Common repairs in San Francisco homes
- Repiping
Many pre-war buildings still have galvanized supply pipe, which corrodes and narrows over decades.
- Sewer Line Repair
Old clay and cast iron laterals under century-old buildings crack and let roots in.
- Bathroom Remodel Plumbing
Remodels in older flats usually uncover original drain and supply lines, and California's fixture rules apply.
What's behind the walls of San Francisco's older homes
The median home in San Francisco was built in 1946, and 75% of homes predate 1980. Homes from that era were typically built with galvanized steel supply lines, cast iron drains and clay sewer laterals, often partly replaced over the years.
- Galvanized steel supply (1900–1960)
- Copper supply (1950–2000)
- Polybutylene (some homes) (1978–1996)
- PEX / CPVC (1995–today)
Emergency plumbing in San Francisco
Call (833) 878-1592Shut off your main water supply if it's safe to do so. The emergencies below are listed most likely first for San Francisco homes, based on local conditions.
Where San Francisco's water comes from
Water from Hetch Hetchy Reservoir in the Sierra supplies up to 85% of San Francisco's water. It is exempt from state and federal filtration requirements because of its exceptional quality, and is disinfected with ultraviolet light and chlorine. [1]
Plumbing services for San Francisco homes
San Francisco plumbing questions
Do I need a water softener in San Francisco?
Rarely. Most of the city's water comes from the Hetch Hetchy system, a high-quality Sierra snowmelt source.
Do I have to upgrade old toilets when I sell or remodel in San Francisco?
California requires single-family homes built on or before January 1, 1994 to have water-conserving fixtures, and permitted alterations trigger replacement of noncompliant ones, such as toilets over 1.6 gallons per flush.
Why are plumbing repairs in older San Francisco buildings so involved?
With most housing built before 1980 and the median home from the 1940s, repairs often run into galvanized pipe, cast iron drains and shared lines in multi-unit buildings.
Sources (2)
- U.S. Census Bureau, ACS 2024 1-year (B25035) · checked 2026-10-01
- SFPUC, 2025 Annual Water Quality Report, City of San Francisco · checked 2026-10-01