Opening: What the Government Sampling Record Shows for 1,2,3-TCP in District Of Columbia
Federal monitoring of DC Water & Sewer Authority’s publicly supplied water found no detections of 1,2,3-trichloropropane (1,2,3-TCP) above the reporting threshold over multiple tests between 2013 and 2015. These results come from tests on surface water sources serving over 600,000 residents, reflecting the system's overall water quality, not individual homes.
1. Number of Samples and What Small Sample Sets Mean
The water system’s record includes eight test results for 1,2,3-TCP, none exceeding the detection limit of 0.03 micrograms per liter. While this limited number provides some insight into system-wide water conditions, it does not capture the full variability possible throughout the entire supply or individual household plumbing. A small sample size means some fluctuations or localized conditions might not be represented.
2. Differentiating Aesthetic Secondary Standards from Health-Based Limits for 1,2,3-TCP
Currently, no federal Maximum Contaminant Level (MCL)—a health-based regulatory limit—has been established for 1,2,3-TCP. The EPA’s detections and reporting levels serve as measures for occurrence but are not health safety thresholds. Some water constituents have secondary standards that address taste, odor, or staining rather than health risks, but 1,2,3-TCP's regulatory attention focuses on health-based concerns, which in this system are recorded as non-detect.
3. Additional Water Quality Questions for Commercial or Industrial Operators
Businesses with larger or more sensitive water demands may consider different testing frequencies, source variability, or specific regulatory compliance concerns beyond household needs. Residential users must be aware that the public system’s data represents aggregate results; commercial operators might need more comprehensive site-specific evaluations to manage operational risks related to 1,2,3-TCP exposure.
4. A Stepwise Approach to Water Quality Verification, from Basic Checks to Laboratory Testing
Households beginning assessment of 1,2,3-TCP concern should start by reviewing publicly available water quality reports for their area. Confirming the absence or presence of 1,2,3-TCP requires direct testing of their home water supply through a qualified laboratory using EPA-approved methods. Consider testing first if there are any unusual tastes or odors or if water is drawn from private wells not addressed by public system monitoring.
5. How Water Source and Sampling Depth Affect Expectations for 1,2,3-TCP
Sampling in this system involves surface water sources. In contrast, private wells drawing from groundwater or shallower depths may have different exposure profiles. The occurrence of 1,2,3-TCP can vary with source type, water treatment, and local environmental factors. Public water system records reflect sampled source water characteristics and treatment efficacy but cannot fully predict localized household levels.
6. Differences Between Public System Records and Private Well Testing for Households
While the public water record indicates no detected 1,2,3-TCP above reporting limits, private well owners must rely on specific testing to determine their water quality. Public system results cannot substitute for individual well assessments. Households dependent on private sources remain responsible for verifying their own water’s safety and quality with appropriate testing.
Summary: Government sampling in District Of Columbia’s public water system shows no detected 1,2,3-TCP above reporting levels, providing a baseline understanding for households. To choose appropriate water treatment, homeowners should verify their own water through testing and then consider equipment designed to reduce 1,2,3-TCP, such as the C-Series 1,2,3-TCP Filter, which ships ready to configure for residential needs.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2014-10-22. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for DC Water & Sewer Authority (DC0000002), DC: 8 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level