What does 'not detected' really mean for VOCs like 1,1-dichloroethane and chloromethane?
When you see a lab report that lists a volatile organic compound (VOC) as "not detected," it refers to the compound being below the method detection limit of the test. For example, the EPA's federal Unregulated Contaminant Monitoring Rule (UCMR3) testing of the NJ American Water Co. - Raritan system serving Union County found no detections above the reporting level of 0.03 micrograms per liter (µg/L) for 1,1-dichloroethane, meaning any concentration present was below 0.03 µg/L or 0.03 parts per billion (ppb). This does not guarantee zero presence, just that the compound was not measurable above that threshold during sampling.
Seasonal water-table changes do not automatically shift solvent plumes near your home
Volatile organics such as halon 1011 and HCFC-22 can move with changes in groundwater levels. However, EPA data collected from 2013 to 2015 from over 200,000 connections in Union County showed only a single detection of halon 1011 at 0.12 µg/L, and no detections of HCFC-22 above 0.08 µg/L. These results represent the entire public system sourced from surface water. Seasonal fluctuations in water levels can relocate solvent plumes, but the extensive sampling suggests stable or very low presence over time in the system as a whole.
Sample size and well scope give context to the VOC figures from the NJ American Water system
The EPA data reflects 36 to 40 samples taken between 2013 and 2015 from this public water system. While that is only a subset of the entire network, the samples represent diverse points in the distribution system serving over 615,000 people. A small number of detections and widespread non-detections across this sampling help form a representative picture of system water quality but cannot specify conditions for any individual household's tap water.
Which household water uses might reveal VOC presence first?
VOCs are volatile compounds, meaning they can evaporate easily into air. Household fixtures like showers or dishwashers release water as mist or steam, possibly inhaling VOC vapors before or without drinking them. Plumbing water for cooking or direct drinking may show less early effect. Monitoring air around water use points can sometimes reveal VOC exposure even when water testing is inconclusive.
How water source type and infrastructure depth affect your VOC expectations
The NJ American Water Co. system in Union County draws from surface water sources rather than deep wells. Surface water is more exposed to environmental changes, but treatment and monitoring practices are managed at scale. Private wells, deeper well penetrations, or different source waters may have distinct VOC profiles, so individual testing is necessary to understand your household’s specific water quality.
Why the volatility of VOCs matters for exposure through daily activities
Volatile organic compounds like MTBE and 1,3-butadiene can vaporize during showering, washing dishes, or other water uses that create steam or aerosol. This means inhalation can be a significant exposure route alongside drinking. EPA monitoring in Union County showed no detections above reporting limits for these compounds. Even so, the nature of VOCs makes household air quality an important consideration if VOCs were present.
In summary, EPA's monitoring of the NJ American Water Co. system serving Union County found VOC detections to be extremely rare and below measurable limits for most tested compounds. This data comes from a wide public system and does not guarantee individual tap water VOC levels. To know your home's water conditions, independent testing is necessary. For households prioritizing VOC reduction, systems like the Fleck VOCs & Industrial Chemicals Filter ship ready to configure and are documented to address volatile organics and industrial chemical contaminants effectively.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-12-07. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for NJ American Water Co. - Raritan (NJ2004002), NJ: 256 results across 7 listed contaminants, 1 detections above the reporting level; no federal MCL for these UCMR-listed VOCs
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