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.
We discovered an error in how our database generated the numbers of households in each tier (group of households in a range of nitrate levels). While the overall number of households is consitent between the maps and the data tables, the query that retrieved information from the database missed certain results and grouped others into incorrect tiers. Three additional households are now correctly reflected in the totals through 7/31, and some households that appeared in an incorrect tier now appear in the correct tier. The errors were due to the way the database identified a few households that had multiple nitrate tests. This affected very few household numbers (the difference in numbers was 1% or less).
All nitrate test results
Nitrate test results at or above 10 mg/L
Nitrate test reults 5 mg/L to 9.99 mg/L
Nitrate test results below 5 mg/L
Summary tables
updated July 31, 2024
Household Nitrate Test Results
| Nitrate Range | Morrow | Umatilla | Total |
|---|
| 0 to 4.99 mg/L | 174
| 718
| 892
|
|---|
| 5 to 9.99 mg/L | 124
| 315
| 439
|
|---|
| 10 to 25 mg/L | 74
| 177
| 251
|
|---|
| Above 25 mg/L | 87
| 67
| 154
|
|---|
| TOTALS | 459
| 1277
| 1736
|
|---|
Households with Nitrate Test Results Above 10 mg/L
| Nitrate Range | Morrow | Umatilla | Total |
|---|
| 10 to 25 mg/L | 74
| 177
| 251
|
|---|
| Above 25 mg/L | 87
| 67
| 154
|
|---|
| TOTALS | 161
| 244
| 405
|
|---|
| Total high results as percent of all samples | 35% | 19% | 23% |
|---|
Water Treatment Installations
| Morrow | Umatilla | Total |
|---|
| 78 | 47
| 125
|
| ---% of eligible* | ---% of eligible* | ---% of total eligible* |
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 above 25 mg/L must rely on bottled water delivery. Plumber workforce constraints have limited the pace of installations.
- 8/19 Update: Today OHA updated numbers of installations to reflect totals through 7/31, which had not been updated from the 6/30 totals. Also, OHA is pausing reporting on percent of eligible households between 10mg-25mg/L nitrate with systems installed. We will post a detailed memo explaining the reasons for this when we post the next update for the reporting period through 8/31, at which time we will resume posting percentages.
Households Receiving Water Delivery
| Morrow | Umatilla | Total |
|---|
277
| 202 | 479
|