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Water Quality Assessment <br />Objectives <br />17 <br />• To determine the degree to which water supply wells are protected against contamination. <br />The evaluation will identify any deficiencies with the well heads with respect to proper well <br />protection components (seals, vents, casing height) and with location of the wells. <br />• To determine the quality of water at each well supplying the homes. Wells will be tested for <br />parameters that are related to health risks as well as for aesthetic qualities. Wells that are no <br />longer used for drinking water supplies are not included in the survey. <br />Methodology <br />All households in the survey area who completed and returned an application were included in the <br />assessment. Of the potential 25 wells in the defined area, 11 applications were received. <br />The sampling collection included analyses of <br />• Total and fecal coliform bacteria <br />• Inorganic chemicals <br />• pH and turbidity <br />• Pesticides <br />• Volatile organic compounds and Petroleum <br />• Nitrates and Nitrites <br />Chain of custody for the samples was assured by direct delivery of all samples to the NC Laboratory <br />of Public Health in Raleigh. As lab analyses were reported from the lab, the results were entered <br />into a master spreadsheet. <br />Water Sampling Results <br />Bacteriologic Quality <br />Of the 11 wells sampled: <br />• two samples were positive for total coliform bacteria <br />• one sample was positive for fecal coliform bacteria <br />• eight samples tested negative for coliform bacteria <br />coliform bacteria, while not pathogenic in and of itself, is used as indicator bacteria for the <br />presence of harmful bacteria. The presence of coliform bacteria indicates that surface water <br />contamination is present in the well, either through a shallow, unprotected vein of water (generally <br />less than 60 feet from the ground surface), or from an inadequate length of casing or other well <br />construction deficiency. For drilled wells, the casing is the metal pipe that extends from the ground <br />surface and goes into solid rock (bedrock) to seal out the shallow groundwater, which is poor in <br />quality. Hand-dug wells and bored wells rely on shallow groundwater and commonly contain <br />coliform bacteria. Shallow wells are also more prone to going dry or getting muddy during extended <br />periods of drought. For these reasons, current Orange County well construction standards require at <br />least 63 feet of casing on all new drilled wells. <br />Page5of11 <br />