Non-potable Water Studies

The SSL is FDA-certified for the examination of seawater, to determine the levels of coliforms in coastal waters.  We are able to determine the levels of coliforms, E. coli, and Enterococcus spp. in non-potable waters in the Houston area and in tributary waters of Galveston Bay.

The SSL has studied the levels of E. coli and Enterococcus spp. in Houston waterways and tributary waters of  Galveston Bay.  Water samples are tested using the IDEXX method (IDEXX Laboratories, Inc.)  and qPCR.  IDEXX detects the bacteria through color change and/or fluorescence of the bacteria under a UV lamp, and enumeration is through a “most probable number” (MPN) method.  The qPCR method enumerates the bacteria, allowing for a direct comparison of the number of bacteria via each method.

IDEXX Quanti-Tray showing clear, non-fluorescent wells negative for coliforms; yellow, non-fluorescent wells positive for coliforms; and fluorescent wells positive for E. coli. The number of positive wells in the Quanti-tray correlates to the MPN of bacteria in the sample.