PlainWater

Okanogan County, Washington

SDWIS compliance plate

Sheet WA047 · Okanogan County 123 sys · 7,257 viol · #1041/3254

VIOL-SEVERE · HEALTH-LOW · RANK-UPPER · PHOTO-FINISH · PFAS-HIGH · SRC-GW · SYS-LARGE · BOOK-FULL

  • VIOL-SEVERE 94.3% flagged
  • HEALTH-LOW 6.5% health
  • RANK-UPPER #1041/3254
  • PHOTO-FINISH ±0.0 pp
  • PFAS-HIGH 100.0% detect
  • SRC-GW GW lead 98%
  • SYS-LARGE 123 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Grays Harbor County (+ 0 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Okanogan County ranks #1,041 of 3,254 counties by people served, and #25 of 39 counties in Washington. See methodology · corpus placement.

Okanogan County standing, mid-flagged corpus third

Flagged-system rate 94.3% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 6.5% is health-based share at or below the lower third (≤ 10.3%) . UCMR5 detect rate 100.0% is UCMR5 detect rate above the tested-pool upper third (> 33.3%) . Population served ranks #1,041 of 3,254 · #25 of 39 in Washington.

Flagged-rate neighbourhood around Okanogan County

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

0% 20% 40% 60% 80% 100% Grant · lowest Kitsap · near Grays Harbor · near Wahkiakum · highest 69.8% 93.9% 94.1% 94.3% 94.3% 94.5% 100%

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

Water Systems

System Name Population Violations PFAS
Omak City Of 4,940 13 Detected
Oroville City Of 3,256 92 -
Brewster City Of 3,235 29 -
Okanogan Water Department City Of 2,921 77 -
Tonasket Water System 2,392 25 -
Pearrygin Lake State Park - Both Cg 2,103 17 -
Okanogan Neighbors 1,600 5 -
Coulee Dam Water Dept 1,359 7 -
Winthrop Town Of 1,350 27 -
Monse-Riggan Camp 1,165 13 -
Pateros Water Department 1,149 93 -
Alta Lake State Park 1,071 11 -
Twisp Town Of 1,044 138 -
Conconully State Park 1,004 16 -
Johns Farms 872 4 -
Okanogan County Fair Water System 867 20 -
Liberty Bell High School 642 704 -
Jaw Farms Inc 636 26 -
Duck Lake Water Association 635 62 -
Brewster Flat Domestic Water Assn 542 35 -
Nespelem Water Dept 510 110 -
P and G Orchards Camp 2 489 102 -
Bridgeport State Park 441 15 -
Riverside Town Of 429 111 -
Washington Pass Well - Methow RD 413 4 -
Sun Mountain Resort 376 387 -
Elmer City Water System 368 16 -
Loup Loup Ski Area 350 8 -
Progressive Flat Water Assn 335 242 -
Conconully City Well 299 17 -
Sandflat Water Association 260 7 -
Suncrest Plat Water System 260 31 -
Conconully Sp Boat Launch 258 5 -
Coleman Butte Water Assn 250 48 -
Loomis Water Users Assn Inc 225 17 -
Riverbend RV Park 222 16 -
Los Reyes Inc 200 0 -
Alta Lake Golf Course Plat 161 751 -
Honeybear Growers 161 130 -
Emerald City Green Machine 155 7 -
Country River Farm 153 11 -
P and G Orchards Camp 3 152 7 -
River Road Mobile Home Park 150 285 -
Klipchuck Cg - Methow RD 149 7 -
Aston Estates 141 51 -
Arrowhead Ranch 140 2 -
Pasayten Peak 129 1 -
Conconully Sp Primitive Area 129 5 -
Tonasket Free Methodist Church 120 5 -
Crumbacher Estates Water System 111 72 -

Compare beyond Washington

Mid-flagged peers for Okanogan County

Cross-state counties nearest Okanogan County on flagged-system share (94.3%) and cumulative violation count (7,257). 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
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.