Is Lake Oswego, OR tap water safe?
Data: U.S. EPA · How we read the data · How we check it
Summary
Portland Water Bureau has 1 unresolved health-based violation on record.
Is it an emergency? No: these findings are about longer-term exposure, and nothing in EPA's data calls for you to stop drinking the water today. If your utility issues a boil-water or do-not-drink notice, follow it.
3 public water systems serve parts of Lake Oswego. The largest, Portland Water Bureau, serves 666,200 people. Your water bill names your system.
Largest system
Portland Water Bureau
666,200 people · Surface water · EPA ID OR4100657
| PFAS | Highest average | Limit |
|---|---|---|
| PFOA Not detected | – | 4 ppt |
| PFOS Not detected | – | 4 ppt |
| PFHxS Not detected | – | 10 ppt |
| PFNA Not detected | – | 10 ppt |
| HFPO-DA (GenX) Not detected | – | 10 ppt |
ppt = parts per trillion. "Highest average" is the highest average at any of the system's entry points, the way EPA compares results with the limits.
Lead: 5.01 ppb at the 90th percentile (Nov 2026, and 9 in 10 homes sampled were at or below it) Below action level
Health-based violations since 2016: 1
Across Oregon, 9 of 123 water systems EPA tested had PFAS above a 2024 federal limit, and 16 systems were above the lead action level in results from the last five years. Oregon results.
Lake Oswego homes and lead pipes
Lead service lines and lead solder were allowed until 1986, so homes from before then are the ones to check. Portland Water Bureau's service line inventory lists 0 lead lines and 0 galvanized lines that need replacing (as of 2024-09-20). Look up your address. Renting? Ask your landlord what the service line is made of, because it's their pipe to replace. How to check your own line.
Housing: Census American Community Survey 2020–2024 5-year estimates for Lake Oswego city (tables B25034, B25003). Estimates for small places have a margin of error.
Other water systems serving Lake Oswego
- Lake Oswego Municipal Water40,000 people · Purchased surface water · Oregon · lists this cityNo PFAS above limits
- Rivergrove Water District4,000 people · Groundwater · Oregon · reported ZIPs hereNo PFAS above limits
How nearby cities compare
| City | PFAS | Lead (90th pct.) |
|---|---|---|
| Tigard 4 mi Portland Water Bureau | None above limits | 5.01 ppb |
| West Linn 4 mi City of West Linn | None above limits | 1.84 ppb |
| Tualatin 4 mi City of Tualatin | None above limits | 4.93 ppb |
| Beaverton 7 mi Portland Water Bureau | None above limits | 5.01 ppb |
| Oregon City 7 mi Oregon City Water System | None above limits | 1.84 ppb |
| Wilsonville 8 mi City of Wilsonville | None above limits | 7.6 ppb |
Lake Oswego ZIP codes (2)
- 97034
- 97035
Questions
Is Lake Oswego tap water safe to drink?
Portland Water Bureau had 1 health-based violation since 2016. Utility data can't show lead from your own pipes: if your home was built before 1986, test your tap. Your utility's annual Consumer Confidence Report is the official summary.
Who supplies water in Lake Oswego, OR?
3 public water systems serve parts of Lake Oswego. The largest is Portland Water Bureau (666,200 people). Your water bill names your system. The EPA ID is also on your utility's Consumer Confidence Report.
Does Lake Oswego tap water have PFAS?
None detected above EPA's reporting limits. Portland Water Bureau had no PFAS detected in EPA's 2023–2025 testing. "Not detected" means below the reporting limit (about 2 to 20 ppt), not proven zero.
Do Lake Oswego homes have lead pipes?
Census estimates put 46% of Lake Oswego homes as built before 1980 (Oregon: 49%). Lead service lines and lead solder were allowed until 1986, so older homes are more likely to have them. Portland Water Bureau's service line inventory lists 0 lead lines. The only way to know for your home is to check the line where it enters the house and test your tap.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.