Lewis and Clark County, Montana
SDWIS compliance plate
Sheet MT049 · Lewis and Clark County 162 sys · 24,270 viol · #765/3254
VIOL-SEVERE · HEALTH-LOW · RANK-UPPER · PHOTO-FINISH · PFAS-CLEAN · SRC-GW · SYS-LARGE · BOOK-FULL
- VIOL-SEVERE 96.3% flagged
- HEALTH-LOW 6.9% health
- RANK-UPPER #765/3254
- PHOTO-FINISH ±0.6 pp
- PFAS-CLEAN 0.0% detect
- SRC-GW GW lead 93%
- SYS-LARGE 162 systems
- BOOK-FULL 7/7 fields
Nearest flagged-rate peer: Big Horn County ( -0.6 pp flagged-rate)
According to EPA SDWIS county population served used on /counties, Lewis and Clark County ranks #765 of 3,254 counties by people served, and #6 of 56 counties in Montana. See methodology · corpus placement.
Lewis and Clark County standing, mid-flagged corpus third
Flagged-system rate 96.3% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 6.9% is health-based share at or below the lower third (≤ 10.3%) . UCMR5 detect rate 0.0% is UCMR5 detect rate at or below the tested-pool lower third (≤ 0.0%) . Population served ranks #765 of 3,254 · #6 of 56 in Montana.
Flagged-rate neighbourhood around Lewis and Clark County
Lowest/highest poles plus in-state counties nearest Lewis and Clark County on % of SDWIS systems with ≥1 violation. Full ladder: /counties.
Water Systems
Compare beyond Montana
Mid-flagged peers for Lewis and Clark County
Cross-state counties nearest Lewis and Clark County on flagged-system share (96.3%) and cumulative violation count (24,270). 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. 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.