Is Lake Oswego, OR Tap Water Safe to Drink?
Lake Oswego tap water meets federal Safe Drinking Water Act standards but 2 of 2 ZIP codes show detections above EPA health guidelines, primarily for lithium. A certified filter is recommended for households that want an additional layer of protection.
Where Does Lake Oswego Get Its Water?
Water in Lake Oswego, OR is provided by 4 public water systems: LAKE OSWEGO MUNICIPAL WATER, PORTLAND WATER BUREAU, RIVERGROVE WATER DISTRICT and WEST LINN, CITY OF.
How Is Lake Oswego Tap Water Treated?
Treated water is disinfected using free chlorine and calcium hypochlorite and ozone. Treatment includes conventional treatment (coagulation, flocculation, and filtration), granular activated carbon filtration and groundwater disinfection.
What's in Lake Oswego Tap Water?
The following contaminants were detected most frequently in Lake Oswego public water systems. 2 of 2 ZIP codes showed detections above EPA health guidelines.
| Contaminant | Peak detected | EPA guideline | ZIPs detected | Status |
|---|---|---|---|---|
| lithium | 12 µg/L | 10 µg/L | 2 ZIPs | Above guideline |
| PFTrDA | 0.007 µg/L | — | 0 ZIPs | Within guideline |
| 8:2 FTS | 0.005 µg/L | — | 0 ZIPs | Within guideline |
| 11Cl-PF3OUdS | 0.005 µg/L | — | 0 ZIPs | Within guideline |
| HFPO-DA | 0.005 µg/L | — | 0 ZIPs | Within guideline |
Health Risk Profile for Lake Oswego
Based on EPA monitoring data, 2 of 2 ZIP codes in Lake Oswego have recorded detections above EPA health guidelines. Sensitive populations such as infants, pregnant individuals, and those with weakened immune systems may benefit from an additional layer of protection such as a certified point-of-use filter.
Best Broad-Spectrum Filters for This Water Profile
This city profile includes PFAS detections, chlorine disinfection, and other dissolved contaminants. Reverse osmosis (RO) systems certified under NSF/ANSI 58 provide broad reduction coverage; for PFAS specifically, confirm NSF/ANSI P473 or equivalent PFAS reduction certification.
8-stage tankless RO system certified to NSF/ANSI 58, reduces 1,000+ contaminants including PFAS, lead, arsenic, fluoride, and nitrates.
See recommendations matched to your exact address: choose your ZIP code below.
Frequently Asked Questions about Lake Oswego Tap Water
Is Lake Oswego tap water safe to drink?
Lake Oswego tap water meets Safe Drinking Water Act requirements but 2 of 2 ZIP codes show contaminant levels above EPA health-based guidelines. A certified point-of-use filter adds an extra layer of protection.
What contaminants are in Lake Oswego tap water?
The most commonly detected contaminants in Lake Oswego water systems include: lithium, PFTrDA, 8:2 FTS. See the ZIP-level reports for exact measurements and EPA guideline comparisons.
Where does Lake Oswego get its drinking water?
Lake Oswego receives water from 4 public water systems, including LAKE OSWEGO MUNICIPAL WATER.
Do I need a water filter in Lake Oswego?
If your ZIP code is among those with detections above EPA health guidelines, choose a filter certified for the specific contaminants shown in your ZIP report. Reverse osmosis is generally the broadest option for PFAS, lithium, and many other dissolved contaminants.
How often is Lake Oswego tap water tested?
Public water systems in Lake Oswego are required by the EPA to test for regulated contaminants on schedules ranging from daily (for microbials and disinfectants) to annual or triennial (for many chemical contaminants). Results are published in annual Consumer Confidence Reports (CCRs). The data on this page reflects the most recent available EPA monitoring results, with the latest sample date of 2025-06-09.
Tap water reports by ZIP in Lake Oswego
- 97034 - Stafford, Lake Oswego tap water report Higher concern
- 97035 - Portland West CCD, Lake Oswego tap water report Higher concern
Water utilities serving Lake Oswego, OR
Service area boundaries are approximate and based on state filings or modeled estimates. Contact your utility to confirm exact service at a specific address.
- GLENMORRIE COOPERATIVE ASSNNo recent federal sampling
Also covers / overlaps with
- Northwest Clackamas CCD, OR · Township
- Portland West CCD, OR · Township
- Stafford, OR · CDP