Toulouse School of Economics, LERNA, Manufacture des Tabacs, 21 allée de Brienne, 31000 Toulouse, France.
J Environ Manage. 2010 Dec;91(12):2696-706. doi: 10.1016/j.jenvman.2010.07.029. Epub 2010 Aug 14.
Using information on a basic or "lifeline" level of domestic water use obtained from a water demand function based on a Stone-Geary utility function, a minimum water threshold of 128 m(3) per household per year was estimated in a sample of municipalities in Southern Spain. As a second objective, water affordability indexes were then calculated that relate the cost of such lifeline to average municipal income levels. The analysis of the factors behind the differences in that ratio across Andalusian municipalities shows that the relative cost of purchasing the lifeline appears inversely related to average income levels, revealing an element of regressivity in the component of water tariffs affecting the least superfluous part of the household's consumption. The main policy recommendation would involve redesigning water tariffs in order to improve access for lower income households to an amount of water sufficient to cover their basic needs. The proposed methodology could be applied to other geographical areas, both from developed and from developing countries, in order to analyze the degree of progressivity of the water tariffs currently in effect and in order to guide the design of more equitable regulatory policies.
利用基于 Stone-Geary 效用函数的需水函数得出的基本生活用水（生命线）水平信息，在西班牙南部的一个市镇样本中，估算出了每户每年 128 立方米的最低用水阈值。作为第二个目标，然后计算了水支付能力指数，将生命线的成本与平均市政收入水平联系起来。对安达卢西亚各城市之间这一比率差异背后的因素进行分析后表明，购买生命线的相对成本似乎与平均收入水平成反比，这揭示了水费构成部分中存在的回归性，该部分影响家庭消费中最非必需的部分。主要的政策建议包括重新设计水价，以便让低收入家庭更容易获得足以满足其基本需求的用水量。所提出的方法可应用于其他地理区域，包括发达国家和发展中国家，以分析现行水价的累进程度，并为制定更公平的监管政策提供指导。
