Government Sampling Overview for King County
Public water system record for Lakehaven Utility District
Monitoring by the EPA under the Unregulated Contaminant Monitoring Rule (2013–2015) found no detections of 1,2,3-trichloropropane (TCP) above the reporting level of 0.03 micrograms per liter (0.03 parts per billion) in 34 samples from this system serving King County households. No health-based violations have been recorded for this constituent in the system’s history.
How a Soil Fumigant Impurity from the 1950s–1980s Reached Deep Groundwater Decades Later
Origin of 1,2,3-TCP in water
1,2,3-TCP originated as an impurity in soil fumigants used mainly between the 1950s and 1980s. Its chemical stability allowed it to persist and migrate slowly, sometimes reaching deep groundwater and surface water over decades.
Transport mechanisms
Leaching through soil and groundwater flow can carry TCP from former agricultural sites to regional water supplies, especially in areas with sandy or permeable soils.
The Agricultural Land-Use History of King County and How It Maps onto Detections
Land use patterns
Historically, King County included agricultural zones where soil fumigants containing TCP impurities were applied. This history helps interpret the regional presence or absence of TCP detections in water.
Detection patterns in public systems
Water systems drawing from surface water sources, like Lakehaven Utility District, showed no TCP detections above reporting limits, consistent with the land use and water source type.
What a Certified Laboratory Test for 1,2,3-Trichloropropane Reports and How to Read It
Test results format
Laboratory results report concentrations in micrograms per liter (µg/L or ppb). Values below 0.03 µg/L are recorded as non-detectable (ND), meaning TCP was not measurable above the laboratory’s detection threshold.
Interpretation of non-detects
Non-detect in this context means TCP was either absent or present at levels too low for quantification, not that it is completely absent.
How Seasonal or Multi-Year Variation Shows in the Record
Sampling dates and frequency
Sampling in the Lakehaven system occurred from August 2013 through September 2014. Within this period, no TCP was detected above the minimal reporting level.
Potential seasonal variation
Seasonal changes in water quality can occur, but no seasonal or multi-year trends suggesting increased TCP presence were found during monitoring.
How to Compare This Area’s Record with a Neighboring County’s Without Overreading It
Regional context
Surrounding counties may have different histories of land use and water sources, which can affect TCP detection. Comparing records should be done cautiously, recognizing each system’s specific characteristics.
Limitations of regional comparisons
Differences in sampling methods, detection levels, and source water types can influence findings and do not establish individual household water conditions.
Granular Activated Carbon Contact Time: Why Bed Depth Matters More for TCP Than for Taste
Carbon filtration principles
Granular activated carbon captures chlorinated solvents like TCP through adsorption. The contact time between water and carbon media greatly influences effectiveness.
Importance of bed depth
Greater bed depth increases contact time, which is critical for reducing low-level chlorinated solvent concentrations that resist other removal methods.
Application in residential water treatment
Using specialized filtration designed for TCP reduction, such as a Pentair 1,2,3-TCP Filter, can offer targeted reduction of this chlorinated solvent when household testing confirms its presence above desired levels.
In summary, regional sampling for 1,2,3-trichloropropane in King County’s Lakehaven Utility District found no measurable TCP in the public water supply. Understanding this constituent’s history, testing results, and filtration options guides household decisions on whether to pursue testing and treatment.
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: 34 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level
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