County profile · EPA SDWIS + UCMR5
Mendocino County, California
147 SDWIS-listed public water systems serve 83,647 people in Mendocino County. Violation rates use that full inventory; PFAS rates use only the UCMR5-tested subset.
- 147
- SDWIS water systems Larger third of counties
- 1,646
- Total violations Middle third of counties
- 77.6%
- SDWIS systems w/ a violation Lower third of counties
- 12.5%
- UCMR5 PFAS rate (8 tested) Middle third of counties with tests
SDWIS compliance plate
Sheet CA045 · Mendocino County 147 sys · 1,646 viol · #658/3254
VIOL-SEVERE · HEALTH-MID · RANK-UPPER · BELOW-PEER · PFAS-LOW · SRC-GW · SYS-LARGE · BOOK-FULL
- VIOL-SEVERE 77.6% flagged
- HEALTH-MID 23.1% health
- RANK-UPPER #658/3254
- BELOW-PEER 1.5 pp cleaner
- PFAS-LOW 12.5% detect
- SRC-GW GW lead 71%
- SYS-LARGE 147 systems
- BOOK-FULL 7/7 fields
Nearest flagged-rate peer: Contra Costa County (+ 1.5 pp flagged-rate)
According to EPA SDWIS county population served used on /counties, Mendocino County ranks #658 of 3,254 counties by people served, and #40 of 58 counties in California. See methodology · corpus placement.
Mendocino County standing, lower-flagged corpus third
Flagged-system rate 77.6% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 23.1% is health-based share in the middle third (≤ 24.5%) . UCMR5 detect rate 12.5% is UCMR5 detect rate in the tested-pool middle third (≤ 33.3%) . Population served ranks #658 of 3,254 · #40 of 58 in California.
Flagged-rate neighbourhood around Mendocino County
Lowest/highest poles plus in-state counties nearest Mendocino County on % of SDWIS systems with ≥1 violation. Full ladder: /counties.
Water Systems
Compare beyond California
Lower-flagged peers for Mendocino County
Cross-state counties nearest Mendocino County on flagged-system share (77.6%) and cumulative violation count (1,646). In-state neighbours stay on the compliance plate above.
Similar flagged-system rate
Nearest cross-state counties by % of SDWIS systems with at least one violation on record.
Similar violation load
Nearest cross-state counties by cumulative SDWIS violation count (all systems in the county).
Read our methodology · Check your water system - how this data is sourced, computed, and verified.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.