Supply. Municipal water supply faces problems almost everywhere. A 1986 survey of 15 Latin American cities found that municipal systems lost between 40% and 70% of their water (203). In India over 40% of the total municipal water supply is lost in transit, before it can reach consumers (170). Even in Malta, one of the world's most water-stressed countries, 30% of the water intended for consumers leaks out of the system instead (131).

Municipal supply systems do not have to lose so much of their water. For example, Geneva, Switzerland, loses only 13% of its water on the way from source to consumer (203). In most cities tightening the joints in the water pipes and fixing leaky community standpipes and household connections would save more than one-third of the water that is currently wasted. Jakarta, Indonesia, for instance, could cut its water losses an estimated 20% by fixing leaky distribution pipes and thus save nearly 12 billion gallons of water a year, enough to provide an extra 800,000 people with tap water (143).

Many cities could manage the water supply better if they could eliminate illegal water taps. In the Philippines, for example, the Water Regulatory Board has estimated that there are about 20,000 illegal connections to Manila's water supply system, both domestic and commercial, which siphon off more than 200,000 cubic meters of water per day. Under the terms of the Water Crisis Act of 1995, anyone caught stealing water can be fined or sent to prison (29).

Demand. "Slowly the idea is spreading that managing demand rather than continuously striving to meet it is a surer path to water security," water expert Sandra Postel has observed (139). Demand management includes several approaches to conserve water, including: economic policies, notably pricing water; laws and regulations, such as restrictions on certain types of water use; technical solutions, such as installing water flow constrictors; and public and community participation (130).

For example, at the 1998 meeting of the United Nations Commission for Sustainable Development, many delegates argued for an economic approach in countries with adequate water distribution systems. In these countries water could be treated as a commodity and sold to consumers at rates that reflect its value in order to encourage conservation (193). Other examples of measures that could reduce municipal demand include (122):

• More use of water-saving household appliances,
• Building codes that require installation of low-flush toilets in new construction,
• Low-water-use landscaping—known as xeriscaping—in arid and semi-arid areas.

Mexico City has responded to this challenge with a multi-faceted water conservation strategy. In 1989 the municipal government adopted strict efficiency standards for all new household plumbing fixtures and appliances. A year later it raised water rates, thus encouraging residents to install more water-efficient faucets and appliances. In addition, the city required that all new toilets installed must use no more than 6 liters per flush compared with conventional toilets that average 16 liters per flush. By 1991 more than 350,000 low-flush toilets had been installed, saving 28 million cubic meters of water a year—enough to meet the annual household needs of an additional 250,000 people. The city's water woes are far from over, but progress has been made in reducing the heavy demand on the water supply system (139, 143).

In most cases introducing a pricing structure that values water properly can make a significant difference (see Valuing freshwater resources in Chapter 7.2). For example, when the water utility of Bogor, Indonesia, tripled, and in some cases quadrupled, water prices, average monthly household water consumption dropped by 30% in less than one year. The utility was able to connect more houses to the existing water supply system and avoided having to build a new system (139).