The Oregon Health Authority (OHA) is working with its partners the Oregon Department of Human Services, Morrow County Public Health Department, Umatilla County Health Department, and community based organizations to provide free safe water services to households in northern Morrow and northwestern Umatilla counties. This is the area known as the Lower Umatilla Basin Groundwater Management Area (LUBGWMA). The maps below show the results of laboratory tests for nitrate in well water. The tables lower on the page provide the same information by the numbers, along with tables listing the number of households that have had water treatment systems installed, and households receiving bottled water deliveries.
For more information about the data that OHA is collecting related to domestic well testing in the Lower Umatilla Basin, please read this
memo from Gabriela Goldfarb, OHA’s Environmental Public Health Section Manager.
All nitrate test results
Nitrate test results at or above 10 mg/L
Nitrate test results 5 mg/L to 9.99 mg/L
Nitrate test results below 5 mg/L
Summary tables
updated August 31, 2024
Household Nitrate Test Results
| Nitrate Range | Morrow | Umatilla | Total |
|---|
| 0 to 4.99 mg/L | 228
| 725
| 953
|
|---|
| 5 to 9.99 mg/L | 146
| 318
| 464
|
|---|
| 10 to 24.99 mg/L | 82
| 181
| 263
|
|---|
| At or above 25 mg/L | 115
| 67
| 182
|
|---|
| TOTALS | 571
| 1291
| 1862
|
|---|
Households with Nitrate Test Results At or Above 10 mg/L
| Nitrate Range | Morrow | Umatilla | Total |
|---|
| 10 to 24.99 mg/L | 82
| 181
| 263
|
|---|
| At or above 25 mg/L | 115
| 67
| 182
|
|---|
| TOTALS | 197
| 248
| 445
|
|---|
| Total high results as percent of all samples | 35% | 19% | 24% |
|---|
Water Treatment Installations
Important note: The table below shows all treatment systems installed by OHA vendors based on test results from OHA contract laboratories starting in 2023. In addition to the systems installed in Morrow County reported below, as of August 31, 2024 OHA's treatment vendors have also installed four treatment sytems in households tested only for nitrates by a laboratory conracted by Morrow County in 2022.
| Morrow | Umatilla | Total |
|---|
82
| 55
| 137
|
100% of eligible
| 30% of eligible
| 52% of total eligible
|
Additional Notes- Reverse osmosis water treatment systems are certified to remove nitrate only up to approximately 25 mg/L, so are only effective in households testing between 10 to 25 mg/L nitrate. Households with water testing at or above 25 mg/L must rely on bottled water delivery. Plumber workforce constraints have limited the pace of installations.
- The table above shows that 100% of households tested by OHA laboratories to date that are eligible for treatment system installation because their nitrate levels tested between 10-24.99 mg/L have had treatment systems installed. We are aware of a number of households tested by Morrow County in 2022 that may be eligible for treatment systems but have not yet responded to multiple efforts to contact them.
- For additional information on numbers reported above, please click here to see a memorandum of explanation.
Households Receiving Water Delivery
| Morrow | Umatilla | Total |
|---|
284
| 219
| 503
|