When a laboratory report lists volatile organic compounds (VOCs) in water, it shows concentrations measured in micrograms per liter (µg/L), also called parts per billion (ppb). These compounds are often solvent chemicals that can originate from industrial processes, fuels, or other sources. Understanding what appears in your local water system's records helps you decide on appropriate water treatment equipment for your household.
Which volatile organic compounds appear in this record and which do not, named from the facts
The EPA's Unregulated Contaminant Monitoring Rule 3 (UCMR3) data for the Lakehaven Utility District, serving over 148,000 people in King County, WA, show no detections of several VOCs above their respective reporting levels. These VOCs include 1,1-dichloroethane, chloromethane, bromomethane, HCFC-22, Halon 1011, 1,3-butadiene, and MTBE. Each compound had zero detections among multiple sample results collected from 2013 to 2015. This means the instruments did not measure their presence above reporting thresholds, but it does not imply absence. No federal maximum contaminant levels (MCLs) apply to these particular compounds, so no violation or safety claim is made by their detection or non-detection.
How seasonal water-table changes move a solvent plume relative to a well screen
Seasonal variations in rainfall and groundwater recharge can shift solvent plumes in surface water supplies like those in King County. These movements influence whether VOCs reach well intakes or water treatment intakes at certain depths. Since the Lakehaven Utility District uses surface water sources, seasonal fluctuations in water levels and flow patterns can affect concentrations. However, the EPA sampling occurred over multiple seasons and locations, providing a broad picture of VOC presence or absence over time rather than conditions at a single well or tap.
How to compare this area's record with a neighbouring county's without overreading it
Comparisons of VOC monitoring results between King County and neighboring counties should consider differences in water sources, geology, population density, and industrial activity. A detection or non-detection in King County reflects sampling from a public water system using surface water, which may differ significantly from systems relying on groundwater elsewhere. Avoid assuming your household water matches another area's record; only direct testing of your water source can confirm individual conditions.
What 'detected', 'median' and 'range' mean in the sampling record on this page
'Detected' means the measurement instrument registered a concentration at or above the reporting level, not that it was above a health or safety limit. Since no VOCs listed were detected above reporting levels in this system, the median and range for those compounds are below those levels or not reported. These terms help describe the distribution of measurements in a large sample set but do not apply to individual household water quality without a test.
What distinguishes this problem from the two problems most often confused with it
VOCs differ from aesthetic issues like taste or staining, which relate to dissolved solids or minerals, and from bacterial contamination, which involves microorganisms. VOC concerns focus on chemical compounds that may dissolve into water and require specific treatment methods. Unlike hardness or iron, VOCs generally need adsorption or advanced filtration rather than ion exchange. Understanding this distinction helps in choosing the right water treatment system for your household.
How many samples and wells stand behind the figures, and what a small sample means
The EPA UCMR3 record for the Lakehaven Utility District includes 34 samples for most VOCs and 11 for MTBE, collected between 2013 and 2015. These samples cover a range of locations and times but do not represent all individual wells or taps. A small number of samples means results provide a general regional snapshot, not a comprehensive household-level assessment. Testing your own water is essential to know specific VOC concentrations affecting your home.
This record describes VOC monitoring results for the public water system serving King County residents through 46,077 connections supplied from surface water, with no health-based EPA violations recorded. For households deciding between water treatment options to address VOCs or solvent compounds, the C-Series VOCs & Industrial Chemicals Filter ships ready to configure and is designed to reduce a broad range of volatile organic chemicals. Refer to the official EPA UCMR3 data at the EPA site for detailed source information.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2014-09-30. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Lakehaven Utility District (WA5341997), WA: 215 results across 7 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level