The Long Island American Water Corporation in Nassau County, including Hempstead (T) and Lynbrook (V), draws its public water supply from groundwater sources. Groundwater flows through underground aquifers before reaching household taps. This natural process can occasionally introduce trace chemicals known as unregulated contaminants, such as 1,2,3-trichloropropane (TCP), into the water system.
1. Granular activated carbon contact time: Why bed depth matters more for 1,2,3-TCP than for taste
The effectiveness of granular activated carbon (GAC) to address contaminants like 1,2,3-TCP depends greatly on the contact time—the duration water remains in contact with the carbon bed. Unlike common taste or odor compounds, chlorinated solvents such as 1,2,3-TCP require deeper carbon beds to provide adequate contact time. Simply put, a thicker carbon bed offers water molecules more opportunity to interact with the carbon and adsorb trace chlorinated solvents effectively, making it an important consideration when comparing treatment equipment for a household.
2. The agricultural land-use history of Nassau County and how it maps onto TCP detections
The presence of 1,2,3-trichloropropane in groundwater often relates to historical land use. This chlorinated solvent was once widely used as a soil fumigant in regions with intense agricultural activity, including parts of Long Island during the mid-20th century. Such past applications have resulted in trace amounts of TCP migrating slowly into groundwater over decades. While current public system monitoring in Nassau County has not detected measurable levels of 1,2,3-TCP above the reporting threshold, understanding this background helps contextualize water quality data and anticipate potential household concerns.
3. The order in which to rule things out, from cheapest check to laboratory test
Households aiming to understand 1,2,3-TCP presence should start with affordable evaluations before pursuing advanced laboratory analysis:
- Visual and taste inspection: 1,2,3-TCP does not affect taste or odor, so sensory checks won’t reveal its presence.
- Municipal water quality reports: Review the Long Island American Water Corporation’s public water system records, which include federal Unregulated Contaminant Monitoring Rule (UCMR3) results showing no detections for TCP above 0.03 micrograms per liter (µg/L, equivalent to parts per billion) between 2014 and 2015.
- Professional water testing: To know the exact TCP concentration in your household water, only a certified laboratory test on your actual supply will provide definitive data, as regional monitoring does not estimate individual well or tap water conditions.
4. Why aesthetic secondary standards differ from health-based limits, applied to this constituent
It is important to distinguish between health-based standards and aesthetic secondary standards for water quality. For 1,2,3-TCP, no federal maximum contaminant level (MCL) has been established, meaning no legal health threshold applies. Secondary standards typically govern taste, staining, or corrosive properties, none of which TCP directly causes. Thus, even detecting a trace amount of 1,2,3-TCP does not imply a health violation or that water is unsafe. A household focused on this constituent should consider treatment technologies based on known performance against chlorinated solvents, not on taste or odor criteria.
5. How to compare Nassau County’s 1,2,3-TCP record with neighboring regions without overreading it
Comparing Nassau County’s absence of 1,2,3-TCP detections with data from adjacent counties where TCP might have been detected requires caution. Differences in land use, groundwater geology, and historical chemical application vary greatly within short distances. Regional monitoring data reflect area-wide conditions for public water systems but do not predict individual household supplies. Interpret comparisons as general context rather than definitive evidence of safety or contamination for any home.
In summary, Nassau County’s public water system record shows no detection of 1,2,3-trichloropropane in the Long Island American Water Corporation supply serving Hempstead and Lynbrook. For households choosing between water treatment equipment to manage potential trace chlorinated solvents, key considerations include selecting systems that provide sufficient granular activated carbon contact time. To address this, the Pentair 1,2,3-TCP Filter ships ready to configure and uses proven technology designed specifically to reduce trace chlorinated solvents in residential water. However, the only way for a homeowner to confirm their water’s 1,2,3-TCP concentration is through a qualified laboratory test of their individual water supply.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-12-14. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Long Island American Water Corporation (NY2902835), NY: 42 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level
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