By NATE LEGUE

nlegue@nwherald.com

WOODSTOCK - The hordes of newcomers expected to flood McHenry County over the next 25 years can get awfully thirsty.

But leaders need to act now to make sure that they have enough water to drink, wash their clothes, and irrigate their lawns, a water-supply expert told a roomful of elected officials Wednesday.

The bottom line? Someday, McHenry County might have to address water shortages the same way dry western regions do: By sharing, rationing and preserving water supplies.

If the county grows to nearly 450,000 people in 2030 as predicted, it will need an average of 63.3 million gallons of water a day, according to a three-year-long county-commissioned study prepared by engineering firm Baxter & Woodman Inc. That is 83 percent more water than the 34.6 million gallons a day required in 2000.

"We don't want to get to the point where DuPage County got, where their wells were going dry, and they had to go to Lake Michigan for water and they had no negotiating power," said Larry Thomas, vice president and chief operating officer.

While the county's underground aquifers have enough water to handle that demand, an estimated 120 million gallon a day capacity, the distribution of water does not coincide with higher density areas in the county's southeastern corner, which includes Algonquin, Lake in the Hills, Huntley and Crystal Lake.

In fact, in 2030, Algonquin Township will need 42 percent more water than its capacity, while Grafton Township will need another 27 percent, according to the study.

"There will be some issues with competition for water," said Pat McNulty, county health administrator. "If you look at the whole county, there's more than enough water, but it's not in the right place."

Thomas made the dire predictions in front of the McHenry County Council of Governments, a group of municipal and county leaders - and urged them not to wait until water shortages reached crisis levels.

"It's best to start addressing this now, instead of when it's troublesome," Thomas said.

In the worst-case scenario, if all the towns and villages build as many houses, stores and factories as their comprehensive plans allow, the county will need 164 million gallons a day.

Those kinds of figures have some leaders listening. While conservation efforts - limiting lawn watering and encouraging low-flow toilets and faucets - can save 7 or 8 percent of total water use, it is not enough to solve the looming problem, Thomas said.

The study recommends that the county hire a staffer to manage groundwater and investigate creating a government authority to regulate wells and dig them in less-populated areas for distribution throughout the county.

The alternative, Thomas said, is running short of groundwater in high-population areas.

To see a copy of McHenry County's water management plan, visit www.mchenryh2o.com