Water Quality Sampling Comparison Shows Minor TTHM Variations Below Legal Limits

ull Page 7 of 8 product are regularly collected at a series of distribution system sampling taps. Analysis was performed by the City’s analysts at the Water Treatment Plant’s laboratory. Results from HSA’s sampling of the Town’s drinking water from northern-most Tap A (IDSE #6) are directly compared to the City’s routine sampling of drinking water from distribution system tap LINL (closest to Tap A). Results from HSA’s sampling of the Town’s drinking water from southern- most Tap B (3230) are compared directly to those from the City’s sampling of that tap. TTHM concentrations from HSA’s November 2008 sampling event are slightly higher than the averages of the results reported from the City’s latest quarterly sampling from tap LINL and tap 3230, respectively. The difference between these results is not relevant since the reported concentrations from the City and from HSA’s sampling event are still less than the MCL. It is noted that the concentration of TTHMs reported from the City’s annual compliance event (collected at the Treatment Plant) is close to the MCL. This is not unexpected as the sampling location (treatment plant laboratory tap) is much closer to the point of disinfection than the distribution system sampling taps. Table 1 includes a comparative array of the detected TTHM’s from City’s monitoring program to those detected from HSA’s November 2008 sampling event as well as the TTHM Standards per rule 62-550, F.A.C. The City Public Utilities Department acknowledges that to keep the potable water product free of microbiologics occasionally requires increasing the concentration of disinfecting chlorine added to the supply water. This results in brief incidences of potable water product with a notable change in the taste and higher concentrations of DBPRs. Concentrations of DBPRs and the stronger taste of chlorine subside with the inevitable reduction of chlorination. CONCLUSION As a measure of the quality of the drinking water product being delivered to the Town by the City, results from HSA’s November 2008 collection of potable water from the northern-most and southern-most distribution system sampling taps revealed target regulated drinking water parameters at concentrations below the MCL standards established in FDEP rule 62-770, F.A.C. A comparative of the results obtained from HSA’s sampling event to the City’s reported annual and quarterly results from 2008 monitoring events found minor variations in reported concentrations for select parameters (see Table 1). These variations pose no concern for the quality of the potable water product being delivered to the Town since all parameter concentrations reported from the City’s monitoring events and by HSA’s sampling event are less than respective MCLs. HOUSE_OVERSIGHT_016687