AWWA ACE93066

This paper discusses New York City studies of structural conservation, that is, water conservation by installing water efficient fixtures. Three models were examined: laissez faire (relying on housing turnover and fixture replacement as a result of normal replacement cycles and economic motivations); subsidized replacement, and mandated replacement. Water Conservation under a laissez faire policy was substantial, more than 1 percent of residential water use. Water use reduction under subsidized and mandatory programs was estimated to be much higher, 3-10 percent. The calculated cost to save 1 mgd ranged from a low of $1.36 million to a high cost of $3.69 million. All three incentives produced a positive cost benefit assuming that the cost per dwelling unit of new capacity is $3,000. Once the fixture model was developed, it was only necessary to add income information to permit analysis of alternative water rate structures. The focus of the water rate structures analyzed was to identify those methods that produced the greatest water use reduction for a given revenue increase. The result of the various alternatives that were analyzed in daily gallons saved per dollar of revenue increase is highest for seasonal with excess use surcharge. Lifeline rate was second, and inclining block rate was third.