Unsustainable population growth projected
to stress California water supply

By Angela Hokanson, Bay City News Service

July 13, 2006

The demand for water for outdoor uses such as landscaping is expected to increase across California over the next 25 years, potentially stressing the state's water-delivery systems, according to a report released yesterday by the Public Policy Institute of California.

The greatest increase in water demand is projected to take place in the hotter, inland areas of the state.

"Lawns are one of the biggest culprits," in the projected increase in urban water demand over the next few decades, according to the report.

Across the state, more than half of all residential water is used for outdoor purposes, the study found.

The rate of population growth, the type of housing under construction, and the overall climate are all factors in how much water is consumed for outdoor purposes in different parts of the state, according to Ellen Hanak, one of the authors of the study, which is titled, "Lawns and Water Demand in California.''

Residences in inland areas of the state use two to three times the amount of water for outdoor uses as residences in coastal regions of the state, the report found. This is the result of the growing presence of single-family, as opposed to multi-family, residential units in inland regions, as well as the larger lots -- and lawns-- that are more common in inland areas.

The amount of water used for outdoor purposes is also higher in inland regions because those areas tend to be hotter and dryer.

Water demand is expected to increase faster in inland counties in part because the population is growing at a faster rate inland than in coastal regions like the Bay Area, according Hanak.

Within the Bay Area, though, recent growth has also been heaviest in the warmer, inland areas -- such as the eastern portions of Contra Costa,

Alameda, and Solano counties -causing water demand to increase, according to Hanak.

Between 1990 and 2000, water use in the Bay Area increased by 7 percent because of the growth in population and construction of housing in the eastern portion of the state, Hanak said.

The recent construction of more multi-family housing in the Bay Area, though, has helped mitigate the increase in water demand in the region, according to Hanak.

Many areas of the state should institute outdoor water conservation efforts over the next few decades, the study found. Potential water conservation policies include: using plants that need less water for residential landscaping; making water irrigation systems more efficient; and instituting a tiered-rate water pricing system, according to Hanak.

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