TTHM (Total Trihalomethanes) violations in Oregon
131 active public water systems in Oregon had a TTHM (Total Trihalomethanes) violation in the past three years, 6 of them in the latest quarter of EPA's data. What TTHM (Total Trihalomethanes) is and why it matters.
Systems with a TTHM (Total Trihalomethanes) violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Row River Valley Water Dist Lane County |
340 | 7 | 1 | |
|
Alder Creek Barlow Water Dist Clackamas County |
300 | 3 | 0 | |
|
Cove Orchard Water Association Yamhill County |
300 | 2 | 1 | |
|
Foley Lakes Mobile Home Park Wasco County |
300 | 5 | 0 | |
|
Kelso Water Assn Clackamas County |
300 | 8 | 0 | |
|
Lakewood Homeowners Marion County |
289 | 3 | 0 | |
|
Rink Creek Water District Coos County |
285 | 4 | 0 | |
|
Sunstone Bear Creek Lincoln County |
275 | 5 | 0 | |
|
Oregon Shores Recreation Club Klamath County |
275 | 4 | 0 | |
|
Silver Spur RV Park LLC Marion County |
275 | 6 | 1 | |
|
Eddyville Charter School Lincoln County |
250 | 2 | 0 | |
|
Fernridge Mobile Estates Lane County |
250 | 7 | 1 | |
|
Petes Mountain Water CO Clackamas County |
250 | 7 | 0 | |
|
Round Lake Water Utilities Klamath County |
250 | 4 | 1 | |
|
Langlois Water District Curry County |
220 | 7 | 1 | |
|
Falcon Cove Beach WD Clatsop County |
215 | 5 | 0 | |
|
Sumpter, City of Baker County |
208 | 3 | 0 | |
|
Laurelwood Water Users Washington County |
200 | 6 | 2 | |
|
MT Hood RV Village Clackamas County |
200 | 6 | 0 | |
|
Sunridge Water INC Umatilla County |
200 | 6 | 0 | |
|
Sunshine Plaza Jackson County |
200 | 11 | 1 | |
|
Timber Water Association Washington County |
180 | 9 | 2 | |
|
Hiland WC Shadow Wood Clackamas County |
175 | 2 | 0 | |
|
Jordan Valley, City of Malheur County |
175 | 3 | 0 | |
|
Otter Rock Water District Lincoln County |
175 | 4 | 0 | |
|
Richland, City of Baker County |
165 | 5 | 1 | |
|
Elderberry Nehalem WS Clatsop County |
160 | 8 | 1 | |
|
Midland Water Association Columbia County |
160 | 8 | 1 | |
|
Burns Paiute Burns · County |
155 | 13 | 3 | |
|
Canyon Ridge Deschutes County |
153 | 2 | 1 | |
|
Bridge Water District Coos County |
150 | 6 | 1 | |
|
Shady Cove MHP Jackson County |
140 | 5 | 2 | |
|
Cinder Butte Village Deschutes County |
126 | 1 | 0 | |
|
Pleasant View Water CO Yamhill County |
120 | 4 | 1 | |
|
Rainbow Rock Village MHP Curry County |
115 | 4 | 0 | |
|
Hidden Meadows Water Assn INC Yamhill County |
110 | 5 | 1 | |
|
Whaleshead Beach Resort, LLC Curry County |
108 | 4 | 0 | |
|
Forum Salem Campus Marion County |
100 | 1 | 0 | |
|
Lost Creek Heights Wtr Assoc Columbia County |
100 | 3 | 1 | |
|
Maple Elsie Water Service Clatsop County |
100 | 6 | 0 | |
|
Wolsborn Farms Water District Washington County |
92 | 2 | 1 | |
|
Inn at Otter Crest Lincoln County |
90 | 4 | 1 | |
|
Rice Hill Owners Association Douglas County |
80 | 2 | 0 | |
|
Chehalem Valley Water Assn Yamhill County |
75 | 3 | 0 | |
|
Forest Park Mobile Village Clackamas County |
75 | 2 | 0 | |
|
Lawson Acres Water Association Douglas County |
75 | 6 | 1 | |
|
Nps Oregon Caves National Monument O&m Josephine County |
75 | 8 | 0 | |
|
Sea Crest Lincoln County |
72 | 1 | 0 | |
|
Evergreen Meadows Wtr Improv Dist Jackson County |
70 | 5 | 0 | |
|
McCuddys Landing Columbia County |
70 | 4 | 2 |
About this data
A system is counted once if any of its violations in the past three years involved TTHM (Total Trihalomethanes), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not TTHM (Total Trihalomethanes) alone.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Oregon records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet.