A difficult decision of whether to more than double wastewater impact fees is before the Kalispell City Council, which will hold a public hearing on the matter Monday night.

Jeff Zauner, a former City Council member and the current chairman of the city’s Impact Fee Advisory Committee, says the decision boils down to determining who will pay for future wastewater system maintenance and expansion costs: Kalispell rate payers or the building and development industry.

Either way, city officials say it has become a pressing matter because of continuing growth and development that threatens to exceed the capacity of the city’s wastewater delivery system, particularly on the west and north sides of town.

The advisory committee advanced a 2012 report conducted by a Morrison Maierle Inc. that calculated the costs of maintaining existing wastewater infrastructure and projected costs of extending that infrastructure.

The council is considering increasing impact fees from $2,499 per equivalent residential unit — a cost last adjusted in 2008 — to $5,757 for every new household.

The $3,258 increase is predicated on a calculation that there will be 2 percent annual development growth in the city.

Zauner said the advisory committee and the council have thoroughly screened the study, which also was the basis for recent new impact fees for city water services.

“The decision that the council has to come up with is not whether the study was accurate, or whether they disagree with the percentage of growth. That has all been decided,” Zauner said. “The decision they have to make is who is going to pay for the increase of maintenance and new build-out costs. The council has two choices: the (wastewater rate payers) of Kalispell or the building and development industry.”

Zauner pointed out that the projected growth rate is highly influential in determining the magnitude of impact fee increases.

“Some people wanted it to be 4 percent,” he said. “The higher the growth rate, the lower the impact fee. The lower the growth rate, the higher the impact fee.”

He said the advisory committee settled on the most accurate growth rate projection and wouldn’t go along with a higher, less realistic rate because residents would be on the hook for infrastructure improvement costs that aren’t covered by impact fee revenue that never materializes.

There are two main components involved with the impact fee increase per household: $545 of the increase is attributed to costs associated with a 2009 wastewater treatment plant expansion but the lion’s share of the increase, $2,558, is almost entirely devoted to covering the cost of anticipated wastewater delivery system extensions and improvements.

Susie Turner, the city’s public works director, said the treatment plant expansion has positioned the city to be able to accommodate growth for years to come.

The plant currently processes an average of just over 3 million gallons per day, and with projected 2 percent annual growth it will handle 4.7 million gallons per day by 2035 and 5.37 million gallons per day by 2041. The plant’s maximum capacity is 5.4 million gallons per day.

Currently, rate payers are covering 78 percent of the bond burden for that expansion, which amounts to just over $1 million annually. The current impact fees cover the other 22 percent.

Terri Loudermilk, the city’s budget resource manager, said the impact fee increase would decrease the percentage of the bond burden on rate payers.

“We would have more impact fee revenue to apply to those bond payments,” she said. The share paid by rate payers “definitely would go down.”

Zauner noted that all of the development that has occurred on the north end of town over the last few years has been possible only because of the wastewater plant expansion.

Similarly, future development depends on the ability to improve or extend its wastewater delivery systems.

The city has identified six improvement projects such as new lift stations and pipe upgrades, that eventually would be undertaken and covered by impact fees.

Also identified are three “interceptor” wastewater line extensions on the west side of town that are expected to cost a total of $13.5 million. The Stillwater Road, Three Mile Drive and Spring Creek interceptors will be needed to divert wastewater volume from “Line A,” a north-south wastewater pipeline that is near capacity.

“The is definitely a need,” Turner said, explaining how Line A is currently running at half capacity but taking into account all platted development to the west, all but 10 household units have been allocated.

For a short-term fix, the city has synchronized three wastewater lift stations in the Three Mile Drive area, freeing up a total of about 145 household units, Turner said. But eventually the additional lines will be needed to serve development in areas that have been annexed on the west side of the city.

And that is what most of the impact fee increase would pay for.

Turner said is possible for developers to pay for additional lines, as was the case with the Silverbrook subdivision on the north side of town, where latecomers are charged a fee to share in the cost of the line that serves the subdivision. But with the three west interceptors having estimated price tags ranging from $1.9 million to $6.1 million, it may not be likely that developers would be willing to bear such high up-front costs.

While much of the building community may oppose the proposed impact fee increases, Zauner noted that some in the same community are concerned that development will eventually be limited without an expansion of wastewater delivery capacity on the west side of town.

Zauner said he hopes there will be a good turnout at Monday’s hearing, not only from the development community but from residents who would bear the costs of infrastructure improvements without impact fee increases. He said the advisory committee made no recommendation on whether the increased fees should be adopted. That is a decision that rests solely with the city council.

“I do expect a lot of people to attend the meeting,” he said. “The council needs to hear from them.”

The council meeting starts at 7 p.m. at City Hall on First Avenue East.

Reporter Jim Mann may be reached at 758-4407 or by email at jmann@dailyinterlake.com.