What a Laboratory Test for 1,2,3-Trichloropropane Actually Lists
When a water sample is analyzed for the chlorinated solvent known as 1,2,3-trichloropropane (TCP), the laboratory report typically shows the concentration of this chemical in micrograms per liter (µg/L) or parts per billion (ppb). For example, a test may report a value such as 0.03 µg/L, which is the reporting level — the lowest concentration that the lab can reliably measure and report. If TCP is present below this level, it will usually be indicated as 'not detected' rather than zero. Understanding these numbers is essential to knowing your water's quality and deciding on any further action.
Why the Reporting Level for 1,2,3-Trichloropropane Is So Low Compared to Metals
The reporting level for 1,2,3-TCP is set thousands of times lower than for common metals like iron or copper because it is a synthetic chemical found in trace amounts. Its detection requires sensitive analytical methods since even very low concentrations might be relevant for aesthetic concerns or regulatory monitoring. Metals typically have higher reporting levels because they occur naturally in higher concentrations and tests for them use different techniques. The low reporting level for TCP allows environmental agencies to monitor its presence in water supplies closely.
What 'Detected', 'Median', and 'Range' Mean in the Sampling Record
Government sampling records from the Water & Power Authority in St. Thomas, Virgin Islands, show that 1,2,3-TCP was not detected above the reporting level of 0.03 µg/L in any of the four samples taken during the 2013–2015 unregulated contaminant monitoring. In this context:
- 'Detected' means the chemical was measured at or above 0.03 µg/L;
- 'Median' is the middle value of the detected concentrations when arranged from lowest to highest; here it does not apply since all readings were below detection;
- 'Range' indicates the span from the lowest to highest measurement found.
No detection above the reporting level does not mean the water is free of 1,2,3-TCP; it means the concentration was below what the equipment can reliably measure. Importantly, the monitoring results do not indicate any health-based violations.
What to Write Down Before Seeking Treatment Advice
Before considering treatment options, household water users should have clear documentation including:
- Results from a certified laboratory test on their own water supply specifying 1,2,3-TCP concentration in µg/L;
- The date and location of the sample collection;
- Any additional water quality parameters measured alongside TCP;
- If applicable, information about the water source type and depth, such as municipal supply or private well.
Having this information allows for accurate assessment and tailored advice. Since public system data are aggregate and do not represent individual households, your own water test result is the basis for evaluating if treatment is needed.
What a Certified Laboratory Test Reports and How to Read It
Certified laboratories analyze water samples by sensitive methods like gas chromatography coupled with mass spectrometry for chlorinated solvents. Their reports list detected concentrations with units in micrograms per liter or parts per billion. When TCP is below the reporting level, the report will state 'not detected' rather than zero. Reading the report carefully, note the reporting level, as this indicates the lowest concentration measurable. A result below this level cannot confirm absence but indicates any TCP present is very low. Compare your result to local regulatory information and decide about water treatment accordingly.
What Changes for a Large Household, a Second Home, or Seasonal Property
The water demand and usage patterns influence how treatment approaches and equipment are selected. Larger households may require systems capable of handling higher flow rates and volume. Similarly, second homes or seasonal properties might benefit from treatment equipment that can idle without damage during periods of low use. The measured 1,2,3-TCP concentration from your water test will guide choosing an appropriate solution that matches your specific water consumption and usage frequency.
In conclusion, the public water system records for the Water & Power Authority in St. Thomas, Virgin Islands, from 2013 to 2015 show no detections of 1,2,3-trichloropropane above the reporting level of 0.03 µg/L. These federal monitoring results are not health-based violations but provide context for understanding your water quality. To address any detected or measured levels of TCP in your household water, the Autotrol 1,2,3-TCP Filter offers a documented solution that ships ready to configure, tailored to the demand level you determine through certified testing.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2014-11-05. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Water & Power Auth. (St. Thomas) (VI0000443), VI: 4 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level