Lake Oswego Water Quality
Oregon
According to EPA SDWIS, Lake Oswego, Oregon is served by 9 community water systems covering about 48,129 people. The same extract lists 5 health-based violation records, most recently coded 5000 in 2019. Counts are historical EPA registry rows, not a current compliance or drinkability score.
Drinking water in Lake Oswego, Oregon is delivered through 9 EPA-regulated community water systems serving an estimated 48,129 people. Each system is tracked in the EPA Safe Drinking Water Information System (SDWIS) under the Safe Drinking Water Act, which requires testing for regulated contaminants, consumer notification of violations, and publication of an annual Consumer Confidence Report.
PlainEnviro's health-based SDWIS extract shows 5 violation records across the 9 active community systems shown here. Monitoring and reporting records are not present in the extract. The records carry 3 distinct EPA contaminant codes: Lead and Copper Rule, Total Haloacetic Acids (HAA5), Coliform (TCR).
A past EPA health-based registry row does not describe water delivered today or current compliance status; utilities notify customers and remediate under state primacy oversight when required. For current water-quality status and treatment practices, review your local utility's most recent Consumer Confidence Report or contact the Oregon drinking water program. All records above reflect federal EPA SDWIS data and are not independently verified against state databases.
Community Water Systems
| System Name | Pop. Served | Violations | Status |
|---|---|---|---|
| LAKE OSWEGO MUNICIPAL WATER | 40,000 | 1 | Health |
| RIVERGROVE WATER DISTRICT | 4,000 | 0 | Clean |
| LAKE GROVE WATER DISTRICT | 3,100 | 0 | Clean |
| GLENMORRIE COOPERATIVE ASSN | 310 | 0 | Clean |
| SKYLANDS WATER COMPANY | 250 | 0 | Clean |
| EXCALIBUR VILLAGE | 180 | 1 | Health |
| CARVER MOBILE RANCH | 110 | 2 | Health |
| WESTWIND MOBILE HOME PARK | 104 | 1 | Health |
| ASHDOWN WOOD WATER COMPANY | 75 | 0 | Clean |
Does this city have health-based water violations?
These health-based records can represent Maximum Contaminant Level (MCL), Treatment Technique (TT), or Maximum Residual Disinfectant Level (MRDL) categories. A historical record does not establish that water is currently unsafe.
| Water system | Contaminant | Begin Date |
|---|---|---|
| CARVER MOBILE RANCH | Lead and Copper Rule | 2019-07-01 |
| CARVER MOBILE RANCH | Lead and Copper Rule | 2019-03-11 |
| WESTWIND MOBILE HOME PARK | Total Haloacetic Acids (HAA5) | 2018-07-01 |
| EXCALIBUR VILLAGE | Coliform (TCR) | 2016-03-01 |
| LAKE OSWEGO MUNICIPAL WATER | Lead and Copper Rule | 2000-01-01 |
What are Lake Oswego's health-based records for?
Lake Oswego's health-based violation records carry 3 distinct EPA codes: some name a substance, others the drinking-water rule that was breached. Counts are records on file in the EPA SDWIS extract, not current test results.
| Contaminant | Records | Systems |
|---|---|---|
| Lead and Copper Rule | 3 | 2 |
| Total Haloacetic Acids (HAA5) | 1 | 1 |
| Coliform (TCR) | 1 | 1 |
Frequently Asked Questions
What does EPA SDWIS list for drinking water in Lake Oswego, Oregon? ▼
How many water violations does Lake Oswego have in this EPA extract? ▼
What contaminants were found in Lake Oswego water? ▼
How many water systems serve Lake Oswego? ▼
Where does Lake Oswego get its drinking water? ▼
How does Lake Oswego compare in Oregon?
Of the 287 Oregon places with at least one community water system on file, Lake Oswego ranks #17 by number of systems (9).
Either side of it: Corvallis (12), Astoria (9), Pendleton (9), Central Point (8)
About This Data
Figures here are the current EPA SDWIS extract joined to the 9 community water systems whose service area lists Lake Oswego, ranked against the 287 Oregon places with at least one system on file. Data current as of 2026-08-25.
Water system data comes from the EPA's Safe Drinking Water Information System (SDWIS). PlainEnviro's violation fetch is restricted upstream to records EPA flags as health-based and then joined to active community water systems. Monitoring and reporting violations are not included.
A health-based violation row in this extract is a historical EPA registry entry. It does not describe water delivered today or current compliance status. Many records are later resolved, and public water systems notify customers when required. For current conditions, contact your local water utility or the state drinking water program.
TRI facility data comes from the EPA Toxic Release Inventory. Facilities shown are those that self-report to the TRI program. PlainEnviro presents this data without advocacy framing.
Read our methodology - how this data is sourced, computed, and verified.