How does King County’s agricultural past relate to 1,2,3-TCP detections?
1,2,3-Trichloropropane (TCP) is a chlorinated solvent historically used as an impurity in soil fumigants from the mid-1900s. King County's mix of surface water sources and past land uses influences the presence of 1,2,3-TCP in the public water system. Although the Lakehaven Utility District, which serves over 148,000 people including this area, gets its water from surface sources, historical agricultural use of such chemicals can contribute trace amounts of TCP reaching water supplies over time through soil and water pathways.
Why does granular activated carbon contact time matter more for 1,2,3-TCP than for taste issues?
Granular activated carbon (GAC) treatment relies on contact time—the duration water is exposed to the carbon—to capture contaminants effectively. For TCP, which is a small, chlorinated organic molecule, longer contact times and deeper carbon beds improve the chance that the solvent molecules adsorb onto the carbon. This differs from commonly addressed taste or odor problems where shorter contact times may suffice. After equipment failure, ensuring that replacement treatment ships with ample carbon volume designed for TCP is critical for proper performance.
What is the recommended order of testing to understand your household’s 1,2,3-TCP situation?
Start with the most accessible checks and proceed to more specific testing:
- Check the operational status of your current treatment equipment since failure might mean it’s no longer controlling 1,2,3-TCP effectively.
- Test your household water using a certified laboratory that offers specific analysis for 1,2,3-trichloropropane to understand your exact concentration.
- If you suspect treatment is needed, consider the documented solution designed to address TCP after you get your test results.
Why is the reporting level for 1,2,3-trichloropropane so much lower than for metals?
Federal monitoring defines the reporting level for 1,2,3-TCP at 0.03 micrograms per liter (parts per billion), significantly lower than typical thresholds for metals like iron or lead. This is because chlorinated solvents can pose health concerns at very low concentrations, and the instruments used must be sensitive enough to detect trace amounts well beneath those of common metals. This low threshold helps regulators and water systems track even minimal presence without suggesting a violation or unsafe condition when detections are below established health-based limits.
What does the Lakehaven Utility District’s 2013-2015 monitoring tell King County residents about TCP?
EPA records show that Lakehaven Utility District's system was monitored for 1,2,3-trichloropropane during 2013–2015 with 34 samples analyzed. None showed TCP above the reporting level of 0.03 micrograms per liter. There is no federal maximum contaminant level (MCL) for TCP currently, and no health-based violation has been recorded for this system. This data indicates that TCP has not been detected at reportable levels in the public water system, but individual household water quality can differ due to plumbing and localized factors. Testing water from your own tap is the only way to know your household’s current condition.
After experiencing equipment failure, choosing to configure a replacement designed specifically for TCP treatment, such as the C-Series 1,2,3-TCP Filter, can help maintain control over this solvent in your household water. The system ships ready to configure with appropriate carbon technology focusing on TCP.
In summary, this page outlined how King County’s agricultural history relates to potential TCP presence, why contact time in carbon beds is critical beyond taste considerations, the testing steps to clarify your household’s water situation, and how to interpret official government monitoring data without overreading detection results. These details support a clear path for King County residents confronting 1,2,3-TCP concerns after their equipment has failed.
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