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If there is no well house with sufficient space, the cost of <br />providing the necessary structure and equipment could total <br />$14,000 or more per installation. <br />3. Calculate the additional cost of labor the city will need to <br />obtain required numbers of first -draw testing samples. <br />City utility operators would be required to obtain samples from <br />residences near the ends of the distribution system and from those <br />that contain lead solder less than 5 years old <br />For water systems that serve less than 500 service connections, <br />the proposed regulations require the city to obtain 10 samples the <br />first year, with new samples required every 5 years thereafter once <br />compliance has been established. <br />Cities serving 500 -3,000 customers would have to conduct sampling <br />'every two years (of 10 samples). The number of samples required <br />increases with the number of water utility service connections: <br />System Size Number of samples required <br />3,300 - 10,000 <br />10,000 - 100,000 <br />over 100,000 <br />20 per quarter /80 per year <br />30 per quarter /120 per year <br />50 per quarter /200 per year <br />The occurrence of lead in city drinking water <br />According to the December, 1986 EPA benefit analysis on reducing lead <br />in drinking water, lead occurs as a corrosion by- product that is most <br />often found in new housing or older housing with new plumbing where <br />the use of lead solder is evident. Newly installed solder is <br />particularly dangerous because it dissolves easily and places those <br />using the plumbing at risk. EPA acknowledges, however, that "...lead <br />concentrations in fully flushed water typical of distribution system <br />water, even under corrosion conditions and with new solder,(my <br />underlining) are generally below the currently permitted lead levels <br />(50 parts per billion) and usually below 20 ppb." <br />EPA has determined that lead occurs as a corrosion by- product and <br />exposure occurs from tap water that can contain significant amounts <br />of lead. Data collected and anlyzed from Culligan water - softening <br />company tests formed the basis for EPA's estimates of occurrence. <br />Highest lead contamination levels occur with exposure to the newest <br />solder. EPA also states thta the risk to inhabitants of older <br />housing indicates that 16 percent of such residents are at risk of <br />exposure to high lead levels. EPA has acknowledged uncertainty <br />about patterns of drinking water use and the extent of installation <br />of plastic piping in new construction that would reduce these estimates <br />PAGE -14 <br />