Do California water utilities know what your pipe is made of?
The pipe running from the water main under your street to your building is called a service line. Who owns it varies; what it is made of matters, because some old ones are lead. This page is about a simpler question than either: does anybody actually know?
Federal rules made every water utility in the country check what its pipes are made of and publish what it found. California’s 3,874 utilities reported on 10,101,290 pipes. This is what those reports add up to.
This is not a map of lead
California’s reports record 14 pipes as lead, out of 10,101,290. It records 929,761 as not identified — meaning nobody has worked out what the pipe is made of. That is not the same as finding lead, and the two numbers should never be read as versions of each other.
How much each utility knows
The 643 utilities serving a thousand properties or more, which between them account for about 97% of every pipe in California.
- Knows almost none of it
- Knows less than half
- Knows more than half
- Knows most of it
- Knows essentially all of it
What the figures show
Every water system in the country had to report what its pipes are made of. These are the things that only show up once the reports are put beside each other.
Almost all of the doubt sits with a few utilities
Of the 643 California water utilities serving a thousand properties or more, 524 already know what nearly every pipe is made of. Most of what is left unknown sits with 84 of them, covering 1,006,142 pipes. Whether anyone can tell you about your pipe depends far more on which utility you have than on where you live.
Knowing is not the same as having looked
Only 22% of California's pipes were identified by somebody digging down and looking. The rest were worked out from old paperwork, from the year the building went up, or from a computer model. So a utility reporting no unknowns has given an answer - not necessarily a verified one.
Two utilities can report the same figure and mean opposite things
ALAMEDA COUNTY WATER DISTRICT and LOS ANGELES-CITY, DEPT. OF WATER & POWER both say they have almost no unknown pipes. The first checked 99% of its 88,162 by digging. The second checked 6% of its 744,960 and worked out the rest another way. Same headline number; not the same thing standing behind it.
One company holds 31% of the state's unknown pipes
California Water Service reports on 32 separate California districts. Between them they cover 3.6% of the state's pipes but 30.6% of the ones nobody has identified - 284,407 pipes, which is 79% of everything the company serves against 9.2% across California as a whole. In 27 of those 32 districts, not one pipe was identified by digging.
Unknown does not mean lead
929,761 pipes have not been identified. 14 are recorded as lead. The first number is not a larger version of the second - it counts pipes nobody has established anything about, which is a different thing from pipes known to be a problem.
The biggest utilities that still do not know what most of their pipes are
Each figure is that system’s own submission to the State Water Resources Control Board. A high share means the system has not established what those pipes are made of — not that it found lead in them.
| Water utility | Pipes | Not identified |
|---|---|---|
| CITY OF FRESNO | 138,316 | 61.8% |
| CWS - BAKERSFIELD | 67,456 | 77.2% |
| SCWA - LAGUNA/VINEYARD | 50,687 | 100.0% |
| CWS - VISALIA | 48,970 | 57.5% |
| CALIFORNIA WATER SERVICE - STOCKTON | 47,015 | 84.7% |
| CITY OF VALLEJO | 37,950 | 95.9% |
| CALIFORNIA WATER SERVICE CO. - DOMINGUEZ | 34,492 | 92.4% |
| CAL-WATER SERVICE CO.-CHICO | 31,115 | 62.3% |
| CALIFORNIA WATER SERVICE CO. - HERM/REDO | 27,481 | 88.6% |
| CALIFORNIA WATER SERVICE CO. - ELA | 27,466 | 97.8% |
| TORRANCE-CITY, WATER DEPT. | 26,855 | 92.2% |
| CWSC SALINAS | 25,259 | 80.3% |
| CITY OF SANTA MARIA UTILITIES DEPARTMENT | 25,058 | 78.8% |
| CALIFORNIA WATER SERVICE CO. - PALOS VER | 24,145 | 97.3% |
| CALIFORNIA WATER SERVICE - BEAR GULCH | 19,291 | 81.7% |
What this does not tell you
- Every figure here is a water system's own submission to the State Water Resources Control Board, read from the State's published file on 2026-09-04. Systems revise these returns, and several have since published newer numbers of their own - the system's own page is the place to confirm anything current.
- This counts service lines, not properties or people. A property can have more than one, and a line is not a household.
- Systems with fewer than 1,000 lines are excluded from the comparison. A small mutual water company with nine unknowns out of forty is not usefully compared with a city, and percentages on small numbers say more about the arithmetic than about the system.
- BelowGrid has not inspected anything. This page counts and divides a public file; it does not verify what any system reported.
Where these numbers come from
The State Water Resources Control Board publishes every California water system’s service line inventory as five county-grouped files. All five were read on 2026-09-04 and the classifications counted. These are each system’s own returns to the State — nothing here is estimated, and nobody has inspected a pipe.
How these answers are produced