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Economic Damages to Households.., 35 N o r.:- CJ~ Inc, for the Santa Ana Watershed Planning Agency (1970) which was in turn derivative of earlier studies; Patterson (1968) on plumbing and appliances; and, of course, Black and Veatch and Metcalf and Eddy. Tbe caveats presented in these reports were not emphasized in the Orange County discussion; instead, the methods of data collection were examined, and only the Metcalf and Eddy study methods were found satisfactory. To update the "primary data" of that report, Orange County designed a personal interview questionnaire which was ad- ministered to 1100 respondents in a modified and stratified random sample, Despite the fact that the average house age was only 11 years and the average time of residence six years, Orange County concluded that significant economic damages could be related to corrosiveness and hardness in water. All of tbe survey data was related to TDS or to hardness. Reasons for using bottled water were not correlated to the percentage using home water softeners, nor to respondent age, although those two factors appear to be critical variables in the survey data, The Metropolitan Water District of Southern California responded to the Orange County Water District report in May of 1972, disputing the approach that showed a linear relationship of TDS and water quality damages, MWD did not dispute the fact that TDS caused damages; rather, the report disputed the direct linking of TDS or hardness to all types of damage. It was at this point in the literature that d'Arge and Eubanks prepared their section for Salinity Management Options for t"e Colorado River, Their review included Black and Veatch, Metcalf and EddYi Orange County, and Tihansky's article, 4 Their analysis found the first three references acceptable but without any reference to the caveats stated by Black and Veatch or Mctcalf and Eddy about attribution of damages to salinity, Instead they were cited as support for a finding of direct damage linkage, Tihansky, on the other hand, was criticized specifically as justification for tbe survey designed by d' Arge and Eubanks, Tihansky was faulted for: his lack of consumer knowledge of expected life or frequency of repair for house- hold items; otber variables such as income or age of housing which the autbors feel need to be addressed; and the fact that Tihansky does not deal with variations in water quality over time (but d'Arge and Eubanks likewise do not men- tion variations in water quality constituents except to select survey areas with constituents as similar as possible - although similarities were not defined). The resulting d' Arge and Eubanks survey in- volved 87 plumbing contractors and sales and repair personnel who were interviewed in person or by mail and who served as the basis for esti- mating household economic damages caused by salinity in their study. In another 1978 study, Consumer Costs of Water Quality in Domestic Water Use, Lompoc Area by the Southern District of the California Department of Water Resources, TDS and hard- ness were again related to household damage. The difference between this study and that by d' Arge and Eubanks is vast. A survey was mailed to residents of the four area communi- ties, to bottled water distributors, plumbing con- tractors, water softener services and appliance centers. A 51.3 percent return rate was achieved. TDS and total hardness were "used to develop relationships between water quality and costs [because] ... Data for TDS and TH con- centrations were available for at least 10 years, Historic data for other significant quality parameters, such as r dissolved oxygen, carbon dioxide, and Langelier (or Saturation) Index], were not available.,,25 Nevertheless, the introductory material to lhe rcport contained several pages of discussion and caveats against the presumption of a linear relationship of damages to TDS and even, to some extent, to hardness, 240ennis P. Tihansky. ~Damage Assessment of Household Water Quality: TOnM;t1 or Ih~ FnV'imnmpnl;t1 Fngin~pring Divi~ion Am~ric::ln Socielv of Civil Fnvn~~,"" Vol. 100, No. EE4, August, 1974, pp. 905.917. 25Califomia Water Resources. Consumer (:mfs p. J2.