Opening: What EPA Sampling Indicates About Frederick's Public Water
The City of Frederick public water system, serving about 54,000 people, has undergone federal monitoring for several volatile organic compounds (VOCs) including 1,1-dichloroethane, chloromethane, bromomethane, HCFC-22, Halon 1011, 1,3-butadiene, and MTBE, with no detections exceeding reporting limits during 2013 to 2015.
1. Interpreting 'Not Detected' at a Laboratory’s Detection Limit
When a volatile organic compound is reported as 'not detected' in these tests, it means the concentration in the sampled water was below the laboratory’s method detection limit — for example, below 0.03 micrograms per liter (parts per billion) for 1,1-dichloroethane. This measurement threshold defines the smallest amount that can be reliably identified, not a zero presence. Therefore, the absence of detection does not guarantee the compound's total absence, only that it is below a level the lab can measure. Household water testing is needed to know individual water conditions.
2. Why Granular Activated Carbon Beds Must be Sized by Contact Time
Addressing volatile organics commonly involves filtration using granular activated carbon (GAC), which adsorbs these solvent compounds from water. For effective VOC reduction, the GAC bed requires adequate contact time—not just flow rate—to allow water to interact sufficiently with carbon surfaces. This timing ensures that VOC molecules have the opportunity to bind, which is critical for compounds like 1,1-dichloroethane or MTBE that are less easy to remove. A system sized without considering contact time may not provide consistent removal.
3. Differentiating Gasoline Releases from Dry-Cleaning Releases in Groundwater Composition
VOCs found in water often stem from various sources, notably gasoline spills or dry-cleaning solvent releases. Gasoline-related VOCs typically include MTBE, a fuel oxygenate, whereas dry-cleaning solvents might contain chlorinated compounds like tetrachloroethylene, not measured in Frederick’s public water sampling. Groundwater contamination profiles differ based on these sources, which influence which VOCs may appear in public water systems. Understanding the source helps determine which compounds to focus on for household water testing.
4. The Influence of Plumbing Materials and System Age Separate from Source VOCs
VOCs reported in public water system data reflect source water and treatment results but do not account for potential changes within household plumbing. Materials such as plastic piping or aged fixtures can impact water chemistry separately from source water VOCs. These in-home factors may affect water quality and should be evaluated independently if concerns about volatile organics or other compounds arise at the tap.
5. How Public Water System Records Differ from Private Well Testing in Establishing Water Quality
The EPA public water system record describes VOC occurrence in the municipal supply at the points monitored, representing broad conditions for the community served. This information does not replace testing of individual household tap or private well water, which can vary significantly due to localized factors and plumbing influences. Residents relying on private wells or experiencing unusual taste or odor should perform thorough laboratory analysis specific to their water source.
In summary, the City of Frederick’s public water data show no detectable levels of certain VOCs above established detection limits, reflecting well-treated surface water. Understanding the meaning of these detection limits, the role of filtration contact time, source-based differences in VOC occurrence, and separate plumbing factors helps households decide when specific water testing and treatment are appropriate. For reducing VOCs and industrial solvents at home, the Pentair VOCs & Industrial Chemicals Filter ships ready to configure to address volatile organic compounds effectively.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-12-09. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for City of Frederick (MD0100015), MD: 108 results across 7 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level