Abstract:  To specify demand in most water allocation problems, researchers face a tradeoff between flexibility and parsimony.  Flexible forms are less constraining on elasticity estimates but require large parameter sets that tend to cause poor out-of-sample forecasts and computational difficulties. Using a five-year panel of Texas municipalities, the parsimonious Stone-Geary form yields estimated demand functions that are comparable to flexible form results. The Stone-Geary specification also provides an estimate of the portion of water use that may not be responsive to price. The knowledge of this “threshold” is useful for analysing price structures and designing conservation policies. (JEL Classification Q25, C23)