US Water Score: B
| Contaminant | Detected Level | EPA MCL | Health Guideline | Status |
|---|---|---|---|---|
| Lead |
9.0
|
15 ppb | 1 ppb | Warning |
UCMR5 occurrence results are screening information, not a finding of regulatory compliance or noncompliance. PFAS rules and compliance dates are evolving.
| Compound | Level | EPA MCL | Health Guideline | Status |
|---|---|---|---|---|
| PFOA | 4.8 ppt | 4 ppt | 4 ppt | Above comparison value |
Water Quality Summary
Tap water quality in Longmont, Colorado (80504) receives an overall grade of B (Moderate-low record-based concern) with a score of 84 out of 100, based on analysis of EPA compliance data, contaminant testing, and violation history. This is 16 points above the Colorado state average of 68. The area is served by 8 water systems providing water to approximately 102,866 people, using surface water sources. Testing has found elevated levels of Lead that warrant attention. Notably, 1 PFAS compound exceeds the EPA final MCL value used for comparison — a significant concern given the persistent nature of these chemicals.
A score of 84/100 means Longmont, CO performs well in the US Water Score model, with only minor system-level concerns. Residents should still review their utility's Consumer Confidence Report for official compliance information and household-specific context.
Health Information
Lead is a toxic metal that can leach from aging pipes and plumbing fixtures.
Even low levels of lead exposure can cause developmental delays in children, kidney damage, and cardiovascular effects in adults. The EPA action level is 15 ppb, but health experts recommend no safe level of lead in drinking water.
Lead enters water primarily through corrosion of lead service lines, lead solder, and brass fixtures — especially in homes built before 1986.
If lead is detected above 1 ppb, consider using a certified lead-removal filter (NSF/ANSI 53) for drinking and cooking water. Run cold water for 30 seconds before use if water has been sitting in pipes.
Common Questions
Based on public water-system records, Longmont, Colorado receives an internal US Water Score grade of B (Moderate-low record-based concern) with a score of 84/100. This indicates relatively few system-level concerns in our model, but it is not an EPA safety rating and does not guarantee tap conditions inside individual homes.
ZIP code 80504 is served by 8 water systems using surface water sources, providing water to approximately 102,866 people. Surface water systems are more susceptible to contamination from agricultural runoff, industrial discharge, and weather events, but typically undergo more extensive treatment including filtration and disinfection.
Lead was reported at 9.0 ppb in public-system records for Longmont, Colorado. This is below the currently applicable EPA action level of 15 ppb, but may be above more protective health guidance; EPA's future LCRI action level is 10 ppb. Household plumbing can materially change tap-level exposure, so consider certified filtration and individual tap testing, especially where children are present.
Yes — 1 PFAS compounds were detected in records associated with water serving Longmont, Colorado, and 1 result exceeded the numerical EPA MCL value used for comparison. UCMR5 occurrence results alone are not a regulatory compliance determination. PFAS rules and compliance timelines are evolving; verify current information with the utility and EPA.
Water systems serving Longmont, Colorado have received 5 violations in the last 5 years. Violations can range from paperwork issues (monitoring & reporting) to serious health-based violations where contaminant levels exceeded safe limits. Review the violation details above for specifics.
Based on detected contaminants (lead, PFAS), residents in Longmont, Colorado should consider: Reverse osmosis (RO) system — most effective for PFAS, lead, and other contaminants. Always look for filters with NSF/ANSI certification for the specific contaminants you want to remove.