Greg and Deby Kohlwes’ landscaping business depends on four trucks, gasoline-powered mowers and other power equipment to keep clients’ yards looking neat.

Even though the Kohlwes fill up their gas tanks at a commercial fleet discount, higher costs are hurting their bottom line.

“It definitely is having an impact,” said Deby Kohlwes of Grounds Professionals Inc. in Mukilteo. “We have four trucks. Two are small trucks, two are large, but none of them gets very good gas mileage.”

Even high-mileage vehicle owners can’t ignore the rising numbers being posted at service stations. Although most stations around Everett were charging between $2.30 and $2.40 a gallon Thursday, the average price in the Seattle-Bellevue-Everett area was $2.29, according to AAA.

That’s 12 percent higher than a month ago, when the average was $2.04, and 46 cents above the average of a year ago.

If prices continue to climb, they could eclipse the record average of $2.35, set during Memorial Day weekend last year, within the next two weeks.

While they’re the inspiration for plenty of everyday grumbling from commuters, gas prices also ripple through the economy.

Rising prices cause “a severe financial impact to our business,” said Peter Carlander at Interstate Distribution, an Edmonds trucking company.

The company has imposed a fuel surcharge on its customers, but that’s only making up part of the increase, he said.

“We’re trying to explain to our customers what we’re going through, and they try to explain to their customers,” Carlander said. “We’re not having much fun, no.”

Jay Behar, owner Behar’s Furniture, said he’s paying a fuel surcharge on every truckload of furniture, then paying more to deliver purchases to customers.

“It gets us at both ends,” he said. “It hurts.”

Back at Grounds Professionals, Deby Kohlwes said companies from which they order bark, rock and other materials have also added surcharges. As a company in a competitive field, she and her husband don’t feel they can pass the increased costs along.

“It’s hard for us to go to a customer and say you need to pay a surcharge,” she said.

Still, with diesel fuel at $2.60 or more at most area stations, it can cost $70 just to fill up one truck.

So the Kohlwes are spending more time with a computerized routing program to ensure their crews don’t waste fuel.

“You’re a little pickier about where you take jobs,” Deby Kohlwes said.

Greg Nothstein of the state’s Energy Policy Division said consumers typically respond to higher gas prices by cutting down on spending elsewhere. His agency found that in 2003, the average Washington household spent $147 a month on gas. Today, that figure would be closer to $198. Annually, that amounts to an extra $600 per household spent on gas just since 2003.

Taking a big powerboat out for a spring ride is discretionary spending for most, though boat owners aren’t grumbling much yet, said Kevin Danberg at the Port of Edmonds. Regular unleaded fuel at the dock is at $2.34, a price that’s remained stable for several weeks. Diesel is at $2.43, better than at most gas stations.

“People kind of like our prices,” Danberg said.

That’s because the port hasn’t needed to fill its two 12,000-gallon fuel tanks since March 12. When it does. boaters may be in for an unpleasant jump in prices.

Jim Wilkinson, owner of Everett Jet Center at Paine Field, said he’s noticed less activity there, with more pilots keeping their private planes in the hangar because of fuel prices. That – and the slowly recovering economy – has “pulled down travel,” he said.

Higher fuel prices also are a burden on airlines. Rising prices could keep US Airways from emerging from bankruptcy, The Washington Post reported Thursday. The airline is expected to pay about $500 million more for fuel than it budgeted last fall, and that’s scaring away investors.

There’s not much hope for lower prices anytime soon. The price of crude oil, the largest single factor in gasoline costs, closed Thursday at $55.40 a barrel on the New York Mercantile Exchange, an increase of $1.41. Oil prices are more than 40 percent higher than a year ago.

Martin Munguia, Community Transit’s public information officer, said some people may be trying to use less gasoline. According to preliminary numbers, the transit service saw an increase in riders the first three months of the year.

Reporter Eric Fetters: 425-339-3453 or fetters@heraldnet.com.