Coon Rapids residents are using a lot less water than a decade ago, nearly 1 billion gallons less a year. The city has cut its usage by an astonishing one-third.

Yet residents will now pay more when they turn on the tap. The average water bill will rise 12 percent this year, not including additional gallons used to sprinkle lawns. It’s the third consecutive year water fees have risen in the north-metro suburb to pay for infrastructure upgrades.

“It’s kind of hard to swallow. You tell people to conserve and their rates go up,” said Council Member Steve Wells.

Other aging, built-out Twin Cities suburbs are facing similar predicaments. Bloomington’s annual water usage has dropped by about 240 million gallons in the last 10 years, yet consumer and business costs have climbed on a nearly annual basis.

The problem is that as the number of gallons billed drops, so does revenue. At the same time, aging pipes, wells and pumps need to be overhauled — and that raises the costs.

“It’s a necessary evil,” Wells said. “We have to raise rates because we still have to pay for the infrastructure and the processing of the water. Nationally we’ve had some glaring examples of people who don’t keep their infrastructure up. We never want to be that city. We’ve always been ahead of the game.”

Water consumption has been cut, in part, because of smaller families and conservation efforts. Technological innovations, including low-flow shower heads and fixtures, also play a role. Low-flow toilets alone use 1.6 gallons per flush, compared to 7 gallons used by commodes made before 1980.

“Even washing machines and dishwashers have gone hyper-efficient,” said Bob Cockriel, Bloomington utilities superintendent. “We are all benefiting from these more efficient replacements. We are serving more people, and they are using less and less water.”

The Coon Rapids City Council grudgingly approved the rate hikes this month, which include both an increase to the base fee and to per-gallon charges.

Sewer fees also will increase by 5 percent. That means the average Coon Rapids water-sewer bill will rise $10 per quarter, to $152.

“We try to break even. That’s our goal — have water sales cover the cost of providing water,” Coon Rapids Finance Director Sharon Legg said. “If you are not selling enough gallons, you have to change your rate structure.”

She stressed that the city’s water fund is in good standing.

“Our fund is not in peril, and water quality is not in peril,” Legg said.

About 80 percent of the 2.4 billion gallons used in Coon Rapids last year went to households, with the balance going to serve businesses.

In Bloomington, about 60 percent of the city’s 4.1 billion gallons used last year flowed to homes and 40 percent to businesses. The Mall of America is the city’s single greatest water user; the hospitality industry, including hotels, is another big user.

Cockriel said his department has a pay-as-you-go approach. Fewer gallons purchased coupled with needed repairs and upgrades to the system have resulted in fee increases.

“Our infrastructure, just like everyone else’s, is aging,” he said. “It has a fixed life like the roof on your house or the tires on your car. Things start breaking, and you need a plan to replace them.”