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Counties → California

Lassen County, California

SDWIS compliance plate

Sheet CA035 · Lassen County 55 sys · 421 viol · #1577/3254

VIOL-SEVERE · HEALTH-HIGH · RANK-MID · BELOW-PEER · PFAS-CLEAN · SRC-GW · SYS-MID · BOOK-FULL

  • VIOL-SEVERE 72.7% flagged
  • HEALTH-HIGH 51.8% health
  • RANK-MID #1577/3254
  • BELOW-PEER 2.1 pp cleaner
  • PFAS-CLEAN 0.0% detect
  • SRC-GW GW lead 100%
  • SYS-MID 55 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: San Luis Obispo County (+ 2.1 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Lassen County ranks #1,577 of 3,254 counties by people served, and #54 of 58 counties in California. See methodology · corpus placement.

Lassen County standing, lower-flagged corpus third

Flagged-system rate 72.7% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 51.8% is health-based share above the upper third (> 24.5%) . UCMR5 detect rate 0.0% is UCMR5 detect rate at or below the tested-pool lower third (≤ 0.0%) . Population served ranks #1,577 of 3,254 · #54 of 58 in California.

Flagged-rate neighbourhood around Lassen County

Lowest/highest poles plus in-state counties nearest Lassen County on % of SDWIS systems with ≥1 violation. Full ladder: /counties.

0% 20% 40% 60% 80% 100% Alpine · lowest Lassen · this county Mendocino · near 70% 70.4% 72.7% 74.9% 77.6% 97.1%

Source: EPA SDWIS (county aggregates) As of 2026-05-15

Water Systems

System Name Population Violations PFAS
City of Susanville 7,811 11 Clean
Cdcr-High Desert State Prison 3,857 20 Clean
Herlong Public Utility District 2,114 2 -
Westwood C.s.d. 1,662 14 -
Lassen Community College Dist. 1,380 7 -
Sierra Army Depot 1,200 19 -
Leavitt Lake Csd 950 2 -
Lake Forest Mutual W.C. 565 22 -
Lassen County Water District #1 450 2 -
Clear Creek Csd-Westwood 400 18 -
Janesville Elementary School 400 16 -
Caltrans-Honey Lake Srra 350 10 -
Spaulding Eagle Lake MWC 317 8 -
Susan Hills Estates WC 252 8 -
Shaffer Elementary School 250 5 -
Dollar General Janesville 250 0 -
Johnstonville Elementary School 230 8 -
Richmond Elementary School 221 10 -
Lnf-Eagle Lake Campgrounds 200 10 -
Long Valley Charter School 196 2 -
Susan River Park Water Co. 140 35 -
Mountain Valley Latter-Day Saints Church 110 0 -
Cal Fire-Intermountain Conservation Camp 108 14 -
Lnf-Bogard Work Center/Cal Trans Srra 100 10 -
Eagle Nest Homeowners' Association 84 18 -
Dollar General Doyle 80 0 -
Pineview Mobile Home Park 80 17 -
Little Valley Csd 70 12 -
Eagle Lake RV Park 68 24 -
Lassen Mobile Home Park 62 16 -
Lahontan Heights Home. Assoc. 56 4 -
Sierra Cascade Nursery 55 1 -
Diamond Mountain Golf Club 54 14 -
Point Horizon Institute 48 6 -
Clear Creek Latter Day Saints Church 40 3 -
Lnf-Eagle Lake Ranger Station 40 8 -
Johnstonville Water System 40 16 -
Lassen Co. Off. of Education 32 8 -
Wayside Inn Market 30 4 -
Doyle Payless Shell 30 0 -
Days End RV Park 27 3 -
Pizza Factory Janesville 25 0 -
Janesville Chevron 25 0 -
Artisan Coffee 25 0 -
Super Y Market and Villa Monte Motel 25 0 -
Leavitt Lake Market 25 0 -
Hallelujah Junction Market 25 0 -
Janesville Fire Hall 25 0 -
Johnstonville Quality Foods 25 0 -
Mountain Meadow Ranch 25 0 -

Compare beyond California

Lower-flagged peers for Lassen County

Cross-state counties nearest Lassen County on flagged-system share (72.7%) and cumulative violation count (421). 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.

4 peers

Similar violation load

Nearest cross-state counties by cumulative SDWIS violation count (all systems in the county).

4 peers

Read our methodology · Check your water system - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.