If you notice anything unusual about the water at your kitchen faucet in Merrimack, it’s unlikely to be caused by 1,2,3-trichloropropane, often called 1,2,3-TCP or simply TCP. This chlorinated solvent has been a concern in some areas, but federal sampling data for the Merrimack Village District, serving over 25,000 people in Hillsborough County, shows no detections above the reporting level.
Why the reporting level for 1,2,3-TCP is much lower than for common metals
1,2,3-trichloropropane is measured at a reporting level of 0.03 micrograms per liter (µg/L), which equals 0.03 parts per billion (ppb). This is thousands of times lower than the reporting levels or regulatory limits for many metals found in water. The low level reflects the sensitivity required to identify even trace amounts of this chlorinated solvent, which can arise from industrial use or pesticide contamination. The federal Unregulated Contaminant Monitoring Rule (UCMR3) requires this sensitive detection to understand prevalence, not to signal a violation or unsafe condition.
Why 1,2,3-trichloropropane resists air stripping and treatment implications
Unlike volatile organic compounds that can be removed by aeration or air stripping, 1,2,3-TCP is much less volatile. This means it remains dissolved in water and does not easily escape as a gas. For households considering treatment equipment, this property means that technologies relying on air stripping will not effectively address this contaminant. Systems that employ specialized filtration media designed for chlorinated solvents are more suitable choices for households concerned about TCP presence.
How seasonal and multi-year variation appears in the Merrimack record
The EPA’s monitoring took place over more than a year from April 2014 through June 2015 at the Merrimack Village District groundwater source. Throughout this period, eight separate tests showed no detections of 1,2,3-trichloropropane above the reporting level. This consistency indicates stable groundwater quality with respect to TCP over multiple seasons and years during that timeframe.
Household water symptoms that do and do not signal 1,2,3-TCP presence
Because 1,2,3-trichloropropane occurs at very low levels and lacks strong odor or taste, typical household water issues like discoloration, unusual taste, or staining are not reliable indicators of its presence. Conversely, symptoms such as chemical odors or staining more often relate to other compounds. Without laboratory analysis specifically targeting TCP, household signs alone cannot confirm or rule out its presence.
Difference between aesthetic secondary standards and health-based limits for TCP
No federal Maximum Contaminant Level (MCL) exists for 1,2,3-trichloropropane, so there are no enforceable health-based limits in public water for this compound. State agencies may have advisory levels or guidelines, but these do not represent violations if exceeded in sampling. Secondary standards apply mainly to taste, odor, or staining potential, which are not typically affected by 1,2,3-TCP due to its chemical properties and low concentrations.
The best next step for a homeowner is to order a certified laboratory test specifically for 1,2,3-trichloropropane on their own well or tap water. This test will provide a definitive measure of TCP concentration in your household supply, distinguishing your water from system-wide monitoring results.
For households choosing equipment to address possible chlorinated solvent contamination, the Autotrol 1,2,3-TCP Filter ships ready to configure and uses technology validated for this challenge. Selecting appropriate treatment depends on knowing your actual water quality through testing rather than relying on regional occurrence data alone.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-06-15. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Merrimack Village District (NH1531010), NH: 8 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level
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