The public water system serving Waipahu-Ewa-Waianae in Honolulu County, Hawaii, reported 1,2,3-trichloropropane (1,2,3-TCP, chlorinated solvent) in some samples from its groundwater sources between 2013 and 2015. While no federal maximum contaminant level (MCL) exists and no health-based violations have been recorded, 4 out of 39 results showed 1,2,3-TCP present above the reporting threshold of 0.03 micrograms per liter (µg/L), with the highest detected at 0.44 µg/L (0.44 parts per billion). This information helps residents understand local water conditions as they weigh treatment alternatives.
If you want to understand how state and federal evaluation benchmarks compare for 1,2,3-trichloropropane
Although the U.S. Environmental Protection Agency (EPA) has not established a federal MCL for 1,2,3-TCP, California enforces a stringent state limit of 5 nanograms per liter (ng/L), equal to 0.005 µg/L, which is much lower than the detection levels reported by the Waipahu-Ewa-Waianae public water system. The absence of a federal MCL means that detections above the reporting level in Honolulu do not signify violations or unsafe water under federal law, but the California limit highlights the extremely low threshold some states use for this chlorinated solvent to address regulatory and health concerns.
If you want to interpret the timing and range of 1,2,3-TCP measurements in the regional records
The federally gathered data spans from July 2013 to January 2015, representing a snapshot from the third Unregulated Contaminant Monitoring Rule (UCMR3). During this period, 1,2,3-TCP detections fluctuated in concentration with a median of 0.201 µg/L among positive results, showing variability in presence or assay sensitivity over nearly 18 months. Because these samples reflect periodic monitoring and are not continuous, residents should consider that actual levels in their own water can differ over time. Confirming individual household water quality requires specific onsite testing.
If you want to assess how much treatment capacity is needed based on household water usage
Choosing an approach to address possible 1,2,3-TCP in residential water involves estimating daily water usage, which dictates treatment capacity requirements. Household demand varies widely—typical indoor water use ranges from 50 to 100 gallons per person per day. A treatment solution must handle peak and average consumption to maintain flow and efficacy. When selecting equipment designed to reduce chlorinated solvents such as 1,2,3-TCP, ensuring sufficient capacity prevents breakthrough and maintains water quality without oversizing, which can add unnecessary expense and complexity.
If you want to identify which household fixtures and processes are most sensitive to 1,2,3-trichloropropane presence
1,2,3-TCP primarily affects water used for drinking, cooking, and bathing. Since it is a solvent with low volatility compared to some compounds, inhalation exposure from shower steam is generally limited but noteworthy. Appliances like ice makers, coffee machines, and water dispensers can concentrate taste or odor impacts if chlorinated solvents are present. Prioritizing treatment on whole-house water or at points of use serving these fixtures can improve perceived water quality and reduce inadvertent exposure.
If you want to distinguish 1,2,3-trichloropropane issues from other commonly confused water concerns
1,2,3-TCP should not be conflated with other water quality challenges such as total dissolved solids, chloride, or volatile organic compounds with different origins or treatment responses. Unlike some metals or disinfectant byproducts, 1,2,3-trichloropropane originates primarily from historical solvent use and agricultural fumigants entering groundwater. Its detection involves specialized analytical methods distinct from routine water hardness or aesthetic measurements. Understanding these differences helps select the correct treatment technology and interpret water test results accurately.
If you want to know how 1,2,3-trichloropropane enters groundwater and the public water distribution in Honolulu's Waipahu-Ewa-Waianae area
Historical agricultural practices employed soil fumigants containing 1,2,3-TCP as an impurity, which leached through soil layers into the groundwater over decades. The Waipahu-Ewa-Waianae water system relies on groundwater wells tapping these aquifers. The presence of 1,2,3-TCP is thus linked to legacy contamination rather than recent industrial spills. Once in the groundwater, 1,2,3-TCP can persist due to its chemical stability and enter the water distribution network, where it is subject to dilution and treatment efforts by the water utility.
To address 1,2,3-trichloropropane specifically, some households consider incorporating proven technologies capable of reducing this chlorinated solvent in water. The Autotrol 1,2,3-TCP Filter is designed to ship ready to configure for residential water treatment applications. It supports treating the volumes a household uses daily while targeting chlorinated solvent reductions effectively.
This summary reflects the federal monitoring record for the Waipahu-Ewa-Waianae public water system as reported in the EPA’s Safe Drinking Water Information System (SDWIS) and Unregulated Contaminant Monitoring Rule (UCMR3) data from 2013 to 2015. For personal water quality, individual testing is necessary.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-01-13. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Waipahu-Ewa-Waianae (HI0000335), HI: 39 results across 1 listed contaminants, 4 detections above the reporting level; no federal MCL
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