Updated

California's drought has put 10 communities at acute risk of running out of drinking water in 60 days, and worsened numerous other health and safety problems, public health officials in the most populous U.S. state said on Tuesday.

Rural communities where residents rely on wells are at particular risk, as contaminants in the groundwater become more concentrated with less water available to dilute them, top state health officials said at a legislative hearing on the drought.

"The drought has exacerbated existing conditions," said Mark Starr, deputy director of the California Department of Public Health.

The state has helped about 22 of 183 communities identified last year as reliant on contaminated groundwater to bring their supplies into conformance with environmental guidelines, but the rest are still building or preparing to build systems, he said.

The contamination warning comes days after President Barack Obama announced nearly $200 million in aid for the parched state, including $60 million for food banks to help people thrown out of work in agriculture-related industries as farmers leave fields unplanted and ranchers sell cattle early because the animals have no grass for grazing.

The California Farm Bureau estimates the overall impact of idled farmland will run to roughly $5 billion, from in direct costs of lost production and indirect effects through the region's economy.

Last month, Democratic Governor Jerry Brown declared a state of emergency, as reservoir levels dipped to all-time lows with little rain or snow in the forecast.

On Tuesday, the state's top public health officials said they were targeting 10 communities for immediate relief, trucking in water when necessary and helping to lay pipes connecting residents with nearby public water systems.

Worst hit is the small city of Willits in the northern part of the state, public health director Ron Chapman said. Also targeted for priority help included tiny water systems throughout the state, one so small it serves 55 people in a community listed simply as Whispering Pines Apartments.

"Small drinking water systems are especially vulnerable to drought conditions," the public health department said on its website. "They have fewer customers, which can mean fewer options in terms of resources like funding and infrastructure."

STAGNANT POOLS, CONTAMINATED WELLS

Linda Rudolph, co-director for the Center for Climate Change and Health in Oakland and a former state health official, said millions of Californians rely on wells and other sources of groundwater where the concentration of contaminants is growing because of dry conditions.

"Many groundwater basins in California are contaminated, for example with nitrates from over application of nitrogen fertilizer or concentrated animal feeding operations, with industrial chemicals, with chemicals from oil extraction or due to natural contaminants with chemicals such as arsenic," Rudolph said.

In addition, as dry conditions turn ponds and creeks into stagnant pools, mosquitoes breed, and risk increases for the diseases they carry, she said at the hearing. Residents with asthma and other lung conditions are also at risk as dry conditions create dust.

The state's firefighters put out 400 blazes during the first three weeks of January, normally the state's wettest season and its slowest for wildfires, according to the California Department of Forestry and Fire Protection.

"We are experiencing conditions right now that we would usually see in August," its website quoted Chief Ken Pimlott as saying.