Pentair VOCs & Industrial Chemicals Filter

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Interpreting ‘‘Not Detected’’ in Laboratory VOC Testing Versus Detection Limits

Government sampling of the Iredell Water Corporation system serving Statesville, NC, reports multiple volatile organic compounds (VOCs) with detection limits that define whether a compound is identified or ‘‘not detected.’p> When a sample’s concentration is below the laboratory’s method detection limit, it is reported as not detected. This does not guarantee the absence of the compound, only that it is below the test’s ability to measure it—such as for chloromethane, bromomethane, HCFC-22, Halon 1011, 1,3-butadiene, and MTBE in this system, which showed no detections above their respective detection thresholds during the 2013-2015 EPA monitoring. For 1,1-dichloroethane, detections were recorded but always below any federal maximum contaminant level (MCL).

Movement of Solvent Plumes in Relation to Well Screens During Seasonal Water-Table Changes

Subsurface solvent compounds can shift position relative to a well’s intake screen depending on seasonal water-table variations. Rising or falling groundwater levels can cause a plume of volatile organics to move vertically or laterally, potentially changing the exposure concentration at different times of the year. This dynamic nature means that a single water test may not capture the full variability of VOCs in well water, which is why public system monitoring averages multiple results over years for a broader picture.

Sizing a Granular Activated Carbon Bed for Contact Time Instead of Flow Rate Alone

Removing volatile organic compounds effectively requires sufficient contact time between water and the filter media. Unlike filters sized only by flow, granular activated carbon (GAC) beds designed for VOCs emphasize prolonged interaction to adsorb solvent compounds thoroughly. This contact time ensures compounds like 1,1-dichloroethane, which was detected occasionally in the Statesville system, are reduced effectively. The Pentair VOCs & Industrial Chemicals Filter uses this principle to address solvent contaminants when previous treatment has failed.

Understanding Measured VOC Concentration Ranges Versus Federal Standards and Their Limitations

The detected concentrations of VOCs in the Iredell Water Corporation system were all below any federal MCLs for these compounds, so no exceedances or violations exist. For example, the highest 1,1-dichloroethane measurement was 0.11 micrograms per liter (µg/L), equivalent to 0.11 parts per billion (ppb), well below any enforceable limit. These data reflect public system monitoring with multiple samples across years, not a single household test. They do not establish what an individual home’s water contains or imply unsafe conditions but rather provide regional context for understanding potential VOC presence.

Which Volatile Organic Compounds Appear in the Statesville Water Records and Which Are Absent

In the EPA’s 2013-2015 unregulated contaminant monitoring for the Iredell Water Corporation system, only 1,1-dichloroethane was detected above laboratory reporting levels in a few samples. Compounds such as chloromethane, bromomethane, HCFC-22, Halon 1011, 1,3-butadiene, and MTBE were not detected at or above their respective detection limits. This presence and absence pattern helps identify which solvent compounds are relevant for that system and which are not currently measurable by the federal survey.

The Influence of Plumbing Materials and System Age on VOC Presence Independent of Source Water

Plumbing materials and the age of household piping can affect volatile organic compounds’ presence and behavior separate from the supply water. Some compounds may off-gas or accumulate in older plastic or rubber components, causing intermittent VOC detections unrelated to source water. This factor underscores that only a laboratory test of a specific home’s water can establish its VOC levels, distinct from the public system sampling.

These government sampling records represent the public water system as a whole, serving over 27,000 people in Statesville through more than 10,000 connections. They provide regional VOC data that indicate occasional low-level presence of certain volatile organics without health-based violations. For homeowners whose treatment equipment has failed, the Pentair VOCs & Industrial Chemicals Filter ships ready to configure and offers documented reduction of these solvent compounds through a carbon adsorption process. More information and data can be found at the EPA’s public water system records for Iredell Water Corporation.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2015-10-29. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA UCMR3 monitoring (2013-2015) for Iredell Water Corporation (NC0149025), NC: 436 results across 7 listed contaminants, 3 detections above the reporting level; no federal MCL for these UCMR-listed VOCs