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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Water quality data for 4 cities serving 338,946 residents
Jefferson County in Colorado has an average water quality score of 60/100 (Grade C) based on analysis of 4 municipal water systems. The county's water systems serve approximately 338,946 residents.
Water quality in Jefferson County is fair, with some cities showing room for improvement. 3 cities have scores below 70, indicating elevated contaminant levels that residents should be aware of. Lakewood has the best water quality at 84/100.
4 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Lakewood Top concern: Fluoride (17.3% of limit) | 84 | B+ | 158,006 |
| 2 | Golden Top concern: Haloacetic Acids (60.7% of limit) | 59 | C- | 24,159 |
| 3 | Arvada Top concern: Haloacetic Acids (66.1% of limit) | 49 | F | 122,991 |
| 4 | Wheat Ridge Top concern: Lead (60% of limit) | 49 | F | 33,790 |
Top detected contaminants across county water systems
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| Lead | 0.007 mg/L | 0.009 mg/L | 0.015 mg/L | 46% | 4 |
| Haloacetic Acids | 26.192 ug/L | 39.632 ug/L | 60 ug/L | 43.7% | 4 |
| Copper | 0.422 mg/L | 0.784 mg/L | 1.3 mg/L | 32.5% | 4 |
| Total Trihalomethanes | 23.687 ug/L | 37.691 ug/L | 80 ug/L | 29.6% | 3 |
| Fluoride | 1.111 mg/L | 1.474 mg/L | 4 mg/L | 27.8% | 4 |
| Nitrate | 2.643 mg/L | 4.442 mg/L | 10 mg/L | 26.4% | 4 |
| Arsenic | 0.003 mg/L | 0.004 mg/L | 0.01 mg/L | 26% | 4 |
| Chromium | 0.024 mg/L | 0.049 mg/L | 0.1 mg/L | 24% | 4 |
Recent violations across county water systems
Showing 10 of 20 recent violations
Water quality in Jefferson County, Colorado reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 4 municipal water systems serving a combined population of over 338,946 residents.
The county shows variable water quality performance, with scores ranging from 49/100 in Arvada to 84/100 in Lakewood. This 35-point spread indicates significant variation in water quality across the county, suggesting different water sources or treatment approaches.
The most prevalent contaminants detected across Jefferson County water systems include Lead, Haloacetic Acids, Copper. All monitored contaminants remain within acceptable levels relative to EPA Maximum Contaminant Levels (MCLs).
Given the water quality challenges in Jefferson County, we recommend that residents invest in water filtration systems. Reverse osmosis systems provide the most comprehensive protection, though activated carbon filters can address many common contaminants. Review your city's specific contaminant profile to select appropriate filtration.
Jefferson County has an average water quality score of 60/100 (Grade C) based on analysis of 4 municipal water systems serving 338,946 residents.
Lakewood has the highest water quality score in Jefferson County at 84/100. View the detailed report for Lakewood.
Given the water quality variation across Jefferson County, we recommend reviewing your specific city's water quality report. 3 cities have scores below 70, where filtration is particularly recommended.
Click on any city in the rankings table above to view its detailed water quality report, including contaminant levels, EPA compliance history, and filter recommendations.