This week, homeowners in Montgomery County face an important choice: selecting the right water treatment technology to address potential levels of 1,2,3-trichloropropane (1,2,3-TCP) in their water supply. This page clarifies common beliefs about this chlorinated solvent using data from the local public water system and guides readers on what to check before deciding.
Why the reporting level for 1,2,3-TCP is set far lower than for common metals
The Environmental Protection Agency (EPA) set the reporting level for 1,2,3-TCP at 0.03 micrograms per liter (µg/L), or parts per billion (ppb), which is thousands of times lower than the levels commonly monitored for metals like lead or copper. This is due to 1,2,3-TCP’s chemical properties as a chlorinated solvent historically used in soil fumigation and its potential for long-term persistence in groundwater. Because it has no established federal maximum contaminant level (MCL), detections above the reporting level are not health-based violations but indicate presence that may warrant attention.
How to compare Montgomery County’s 1,2,3-TCP record with neighboring counties without overreading it
Montgomery County’s public water system, Aqua PA - Main System, serving over 800,000 people, recorded 52 measurements from 2013 to 2015 under EPA’s Unregulated Contaminant Monitoring Rule 3 (UCMR3). Of these, 4 samples detected 1,2,3-TCP above 0.03 µg/L, with the highest concentration at 0.169 µg/L and a median of detected values at 0.0905 µg/L. Neighboring counties may report different detection frequencies and concentrations based on varying source waters and histories, but such regional differences should not be equated with individual household water quality. Comparisons help provide context but cannot predict specific well or tap conditions.
What questions commercial or industrial users consider that residential households do not
Commercial and industrial operators often evaluate maximum contaminant levels, process impacts, and regulatory compliance related to chlorinated solvents. They may require equipment rated for higher flow volumes and tailored to reduce TCP concentrations to below certain thresholds for process requirements. Residential households generally focus on ensuring safe, palatable water and protection from aesthetic or secondary concerns. Their decision usually revolves around selecting appropriately sized equipment that addresses local detection records while fitting household water demand.
How 1,2,3-TCP enters groundwater and distribution systems in Montgomery County
1,2,3-TCP in Montgomery County’s water mainly results from its historical use as an impurity in soil fumigants between the 1950s and 1980s. Over time, this chlorinated solvent migrated through the soil to reach deep groundwater sources that supply surface water systems. The public water system draws from these surface waters and treats them before distribution. Detections in the distribution system reflect this legacy contamination, though concentrations vary by location and treatment efficacy.
What to write down before seeking advice on water treatment
- Confirm your water source type (surface or groundwater) and whether your supply is connected to the Aqua PA - Main System or a different provider.
- Obtain a recent water quality report or test results for 1,2,3-TCP or chlorinated solvents specific to your household’s tap water.
- Note your household water demand, including peak daily usage, to match potential equipment capacities.
- Identify any local advisories or additional contaminants of concern within your system’s water quality profile.
With this information, you can evaluate options suited to your specific water quality and household needs.
Ultimately, the critical test to resolve concerns about 1,2,3-trichloropropane in your home water is a direct laboratory analysis of your tap water. This confirms your household’s specific concentration, guiding treatment decisions. For targeted mitigation of 1,2,3-TCP detected in Montgomery County water supplies, equipment such as the C-Series 1,2,3-TCP Filter ships ready to configure and is designed to address this chlorinated solvent effectively.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2013-10-31. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Aqua PA - Main System (PA1460073), PA: 52 results across 1 listed contaminants, 4 detections above the reporting level; no federal MCL