Wayne Olfert knew his town of Rockford had boosted water and sewer rates, but he was shocked last week when he got his latest bill.

"I thought it had to be for three months," said Olfert of the charges, which had more than tripled. "When my wife said, 'No, that's just for one month,' I blew a gasket."

Olfert wasn't alone. An increase in water and wastewater rates, combined with a new way of calculating sewer bills in the summer, socked some people in the west metro exurb with huge increases. Homeowners used to paying $150 a month got bills for $500, sometimes even more.

About 250 outraged residents packed Rockford's fire hall Thursday night, where they heard about plans to undo parts of the new system that had churned out some bills City Administrator Dan Madsen acknowledged were "ridiculously high."

"We get it; that's why we're here," Madsen told the crowd. He said that when the city had tested the new system on some random bills this spring, it hadn't found any glitches.

"You found them now!" a small chorus called out from the back of the room.

The City Council approved the changes in June, aiming to erase a serious deficit in Rockford's utility fund that no longer can be addressed by inter-fund transfers. The financial pressures are about to increase with debt service on a $4.795 million bond issue that will finance two utility projects.

The council approved a 65 percent increase in the water rate and a 38 percent rise in the wastewater rate. It also OK'd a new method for determining people's summertime sewer bills based on their summer water usage.

Rockford previously had averaged people's water use in the winter and used that figure to calculate residents' wastewater bills in the summer. But that method resulted in inequities, Madsen said. For example, people who left town for the winter would wind up having extremely low summertime sewer bills.

But the new method doesn't separate indoor and outdoor water use. That means those who use more water sprinkling their yards can be unfairly charged for water that doesn't go down sewer lines.

Formula jacks up bills

Mike Finger said the new calculation caused sewer usage on his bill to jump from 7,000 gallons in July 2013 to 33,000 gallons this year. The skewed figure, along with increased rates, triggered a $300 increase in his bill, to $440.

Finger said he typically sprinkles his yard every other day and his 10-year-old daughter uses water for her vegetable garden. "I'm proud of my property, and I want it to look nice," Finger said. He said the city should be encouraging residents to improve their property values.

Madsen said the city didn't do a good job of explaining that people could avoid inflated sewer bills by installing a separate "deduct meter" to record water usage not disposed of through the sewer system. In addition to modifying some of the rate increases, the city is considering offering the meters for sale for $150. Residents would have to hire plumbers to install them at a cost of $300 to $500.

Several people at the meeting were irate at having to pay for the meters and urged city officials to go back to the averaging method for sewer bills. One of the few light moments came when a homeowner shouted, "Do I need a permit to build an outhouse in my back yard?"

Next week, the council will consider the deduct meter issue and other changes to delay some rate increases and spread them out over time. Residents criticized city officials for not addressing deficits sooner, leaving little choice except for drastic action now.

Finger said it's unreasonable to expect people to absorb a 65 percent water rate increase all at once. "If I had a cable service that told me my rate was going up by 65 percent, I wouldn't have cable anymore," he said. "Unfortunately, I can't get rid of my water."

Susan Feyder • 612-673-1723