Lake Oswego, OR: 10 Violations — 86/100 (2026)
2 ZIP codes · 11 water systems · Updated 2026-06-03
In current tracking cycles, Lake Oswego records above-average water quality outcomes for OR; compliance history over recent years shows few departures from federal standards and no systemic failures across its water systems.
How Lake Oswego Compares
Data: EPA SDWIS Last verified: 2026-06-03
Lake Oswego Water: The Quick Version
- Your city's water systems recorded 10 violations in the past 5 years.
- Average lead level: 0.0015 mg/L.
- Homes built before 1986: 63% — older plumbing may contain lead solder.
- Estimated remediation: $2,150 per household.
- CDC health risk index: 12.12 — above typical levels.
Water Systems Serving Lake Oswego
3 water utilities share the residential service territory in Lake Oswego, OR — out of 11 total systems in federal records.
Overview
We track water quality and home safety data for 2 ZIP codes in Lake Oswego, Oregon (population ~46,994), covering 11 community water systems serving approximately 772,456 people region-wide.
2 of 2 ZIP codes (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Home Safety Score
Average Home Safety Score for Lake Oswego: A (86/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Lake Oswego water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0015 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 3 (Low Risk)
- Zone 1 (High): 0 ZIP codes
- Zone 2 (Moderate): 0 ZIP codes
- Zone 3 (Low): 2 ZIP codes
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | 12 | 2 |
| Stage 1 DBP Rule | Treatment Technique | 3 | 2 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 97034 | B | 5 | 0 | Lake Oswego Municipal Water |
| 97035 | A | 5 | 0 | Lake Oswego Municipal Water |
All ZIP Codes in Lake Oswego
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
CDC Health Data for Lake Oswego
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Key Contaminants Detected in Lake Oswego
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
How Old Is Lake Oswego's Housing Stock?
With 63% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Decades of residential development in Lake Oswego took place before the two main regulatory milestones that reduced plumbing-era lead risk: the phase-out of lead pipes before 1970, and the federal ban on lead solder in 1986. With a median build year of 1981, the housing stock here is anchored in that earlier period. The distinction between pre-1970 and 1970-to-1986 construction matters: the oldest homes may have lead pipes in the service line and lead solder in the copper joints, while the 1970-to-1986 tier still carries the solder risk even after lead pipes became less common. Together, these two risk layers affect a majority of the residential properties in the city — a fact the aggregate water quality data doesn't directly reveal.
Over half of homes in Lake Oswego were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
Lake Oswego: Remediation Cost in Perspective
Placing remediation in the context of Lake Oswego's property market, the equity share is low — most homeowners here are weighing a financial commitment that fits comfortably within routine property planning, far from the threshold where remediation becomes a material equity decision rather than a standard upkeep consideration.
Remediation costs in Lake Oswego are relatively low compared to home values. The $1,500–$3,250 estimated range is a small fraction of median property value. Home values are 146% above the Oregon average.
Protecting Children from Lead in Lake Oswego
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Reading the local data together points toward a structural gap that matters more here than in low-exposure communities. 63% of Lake Oswego stock comes from the pre-rule era, and citywide monitoring either approaches or sits beyond the federal benchmark under Lead and Copper Rule sampling. A baseline kit fits the routine-diligence category, with certified filtration available via retailer networks where confirmed faucet results warrant additional measures.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Lake Oswego
Taken together, Lake Oswego's 121 NFIP flood insurance claims and 100% FEMA flood zone coverage place it in the moderate range of exposure. That middle position has specific implications for water quality. The contamination pathways that flooding can open — surface water overwhelming treatment facility intake, floodwaters infiltrating private wells, distribution pressure changes creating backflow — are not constant risks in a moderate-exposure community. But they do become active during significant flood events, and the claim record here indicates enough of those events to make flood timing an occasional factor in local water quality conversations.
Lake Oswego has a moderate flood history with 121 FEMA claims averaging $40,404 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$2,150</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
Deep Dive Reports
Detailed analysis for Lake Oswego, OR