Interlocal agreement stregthens bonds for officials in Columbia, Spring Hill

By KATE COIL

TT&C Assistant Editor

A new interlocal wastewater agreement is strengthening bonds between two Middle Tennessee cities, bringing significant infrastructure investment to both.  

Officials in both Columbia and Spring Hill recently approved the regional wastewater infrastructure agreement, which will connect a 12-inch sewer line from the future site of the Spring Hill Water Reclamation Plant to the northern portion of Columbia’s city limits and the presently under-construction Columbia Wastewater Treatment Plant.  

In addition to bringing online new facilities and technologies aimed at treating wastewater, the agreement works to protect the vulnerable Duck River Watershed while fostering collaboration between the cities.  

In August 2025, the city of Spring Hill was put under a sewer moratorium(opens in a new tab) by the Tennessee Department of Environment and Conservation (TDEC). The city had begun work on a new plan for its water and wastewater infrastructure, Pure Water Spring Hill,(opens in a new tab) two months before the moratorium was issued. Spring Hill Mayor Matt Fitterer said the idea for the partnership began with a Spring Hill citizen.  

“The idea originally came from a community member who reached out  when Spring Hill paused new permits, with the suggestion that a partnership with Columbia might provide temporary relief while Spring Hill worked through the Pure Water Spring Hill project,” Fitterer said. “From there, Mayor Molder and I had a conversation about the idea.”  

For Columbia Mayor Chaz Molder, the project began with a phone call. 

“This really originated from the relationship between two mayors,” Molder said. “Spring Hill Mayor Matt Fitterer and I have had a relationship and open line of communication since he was first elected as mayor. I have worked with three Spring Hill mayors during my eight years, and I find Mayor Fitterer to be someone who is really forward thinking. I credit his idea to call me to see if there was any opportunity for conversation. I believe anytime you sit down and have a conversation you never know what might come out of it.” 

While both mayors wanted the idea to work, they had to make sure it could work. A meeting was organized to include the mayors, city managers and administrators and wastewater officials from both cities to see what could be worked out.  

A WORKING AGREEMENT 

Columbia City Manager Tony Massey said Columbia city staff went into the meeting with their Spring Hill counterparts with an open mind. 

“We did not say yes, we didn’t say no, but we said we’ll look into it,” Massey said. “Spring Hill actually paid for the engineering firm we use to do a study to determine if we had the capacity to handle their sewer, where the connection would be, and would our pipes be able to handle it. The answers all came back yes, so that led to us meeting with them again.” 

The city of Columbia is in the process of replacing a wastewater treatment plant originally constructed in the 1970s.  

“One of the things that made this feasible is that we have a new wastewater treatment plant coming online in 2027. We will be able to more than double our capacity of what we can handle. That will allow us to not only take care of our current needs but also let the city of Columbia literally double in size and we would still have the capacity to take Spring Hill’s sewer. Really, this was great timing for them to approach us.” 

Columbia Wastewater Director Donnie Boshers said his first question was about how much volume Spring Hill would need Columbia to handle. In return, Columbia will accept at minimum 500,000 and at maximum 1.5 million gallons of wastewater per day from Spring Hill for treatment, which will then be discharged into the Duck River with the rest of Columbia’s wastewater 

“Right now, our existing facility is a 14 million gallon a day plant and we typically handle 6 to 7 million a day, so even with the new plant, what they needed might not have been a concern,” Boshers said. “At our new plant, we are going to be at 38 million gallons a day maximum. For us to not be able to handle it, our customer base would have to double in size, which doesn't happen overnight.” 

The timeline also worked out for Columbia’s new wastewater plant to begin operating in 2027 while Spring Hill will likely not be ready to make the sewer connection until mid-2028 because of the time needed to design, bid, and build the lines, Boshers said.  

Knowing that the project was feasible, both sides sat down to draft an agreement. Massey said it became apparent Columbia could even generate revenue from the project.  

“It just kind of came together, and we wanted to be as fair as we could be,” Massey said. “We looked at the Spring Hill sewer rate and what they charge to their own customers is what we are charging them. We figured we couldn’t get more fair than that.”  

Approved by both the Columbia City Council and Spring Hill Board of Mayor and Aldermen, the interlocal agreement has Spring Hill providing $12 million to Columbia, $9 million of which will connect Spring Hill’s infrastructure to Columbia’s wastewater system and $3 million that will upgrade Columbia’s Carter’s Creek Pike Pump Station. Spring Hill will be responsible for maintaining and funding infrastructure from its city limits to the connection point.  

Massey said Spring Hill’s Board of Mayor and Aldermen appropriated the $12 million early on to show their commitment to the project.  

“One of the things determined during that engineering study was that the pump station needed upgrades, and Spring Hill was ready to do it,” he said. “We knew at some point in the future we would have to do that upgrade on our own due to the age of the pump station. Having Spring Hill do that will be $3 million savings on our sanitary sewer system, which is not a bad deal.” 

Columbia will also receive $21 million in revenue over the first ten years of the agreement, which will be kept separate from the sewer system’s operating costs and instead be used for capital projects – such as the debt service on the new treatment plant and extending sewer lines toward Interstate 65.  

“At the 500,000 gallon level, using their rate, we are looking at approximately $21 million in new revenue and that’s on the low end,” Massey said. “If it’s on the high end of 1.5 million, that’s $62 million in revenue. We have never entered into agreement for the city of Columbia that will generate this type of revenue.”  

While the agreement lasts for 30 years, municipal officials will revisit it each decade. Massey said that language was included so future officials could make the decision to continue the partnership if the project is still needed.  

PROTECTING THE DUCK RIVER 

Environmental concerns are another issue both communities face. Both communities are served by the Duck River Watershed, which is the one of the most biodiverse rivers in North America and is home to more than 50 species of mussels, more than 20 species of snails, and more than 150 species of fish. 

Columbia’s water and wastewater systems empty directly into the Duck while Spring Hill’s utilize Rutherford Creek, a tributary of the Duck. The line where the two wastewater systems will connect is known as the Rutherford Creek line because it runs alongside the creek near some of Spring Hill’s wastewater and water facilities.  

“Our permit limits are pretty tight because we discharge into the Duck River,” Boshers said. “That was, of course, a consideration for this project. We have pretreatment programs, and the city of Columbia already serves the GM plant and the new battery plant in Spring Hill. At this time, Spring Hill does not have any industrial users, which we took into consideration for this agreement. The timeline works while we wait on a new plant because we can continue to meet those limits. We want to ensure the Duck River and all the creeks and streams around us are taken care of, because we all live here. We send monthly reports to TDEC and the EPA, and work hard every day to maintain our permit limits. We are not allowed to take anything from anybody – regardless of who it is – that could hinder our plant.”  

Boshers said the new plant speeds up a natural, chemical-free process that makes wastewater safe to return to the river. Once disinfected with ultraviolet radiation, the treated water is then safe to release. 

“Our new plant is an extended aeration plant. We will have oxidation ditches that will biologically remove nitrogen and phosphorous. We manipulate the organisms in these ditches. There are areas where there is no sunlight, no air being discharged into it, and fans or motors that can be sped up or slowed down depending on what we want them to do. At the old plant, it goes through seven or eight individual processes to create our final product where this new facility will only take three.” 

Other projects are also in the works to ensure the watershed remains protected. Spring Hill is working to reduce its water footprint and its utilization of the Duck through an advanced purification process involving its wastewater and water treatment plant. The process will recycle water and reduce withdrawals from the Duck using reservoirs with the projected expected to be completed by Memorial Day 2030.  

At the same time, Columbia Power and Water Systems (CPWS) and the city of Columbia  have gotten approval from the newly formed Duck River Watershed Planning Partnership to increase its intake from the Duck from 20 million to 32 million gallons of water per day. The $500 million project includes building a new water main and a new water treatment plant to meet growing drinking water needs in the CPWS service region. 

While the interlocal agreement was not approved by TDEC, Massey said they have been kept apprised of it and will ultimately approve Spring Hill’s sewer lines connecting to Columbia’s. 

“TDEC has shared with us that they consider this project a model for municipal utilities to use in the future,” Massey said. “We are sort of blazing a trail here with this agreement.” 

GROWING CHALLENGES 

Mayor Fitterer said it is no secret both cities are experiencing growth-related pressures.  

"Our responsibility as local leaders is to provide the infrastructure and public services our residents and businesses need while doing so in a fiscally responsible manner,” he said. "Sewer infrastructure is one of the fundamental challenges that growing communities must address. Water and wastewater infrastructure don't always fit neatly within city limits, and the challenges associated with providing these services certainly don't stop at municipal boundaries. As Middle Tennessee continues to grow, our communities will need to think more regionally about infrastructure, capacity, and the responsible use of public resources.” 

Mayor Molder said the project allows both cities to achieve common goals.  

"Out of challenge, often times, we can come up and find opportunities,” Molder said. “We’ve turned this challenge into an opportunity for Spring Hill to have additional capacity and Columbia to generate revenue and have some improved infrastructure at the same time. I think this moment in time of rapid growth for our region means we have to find new ways to work together for the betterment of our region. I think it’s a compliment to our region that people want to move here. I think we have to balance that compliment with the fact that people who have lived here for the majority of their lifetime are not faced with the burden of paying for this growth and need for infrastructure. When we come up with creative solutions to the problems, that benefits our community residents of today and our residents of tomorrow.” 

Ultimately, Mayor Fitterer said the goal is to provide citizens with the best service possible on both sides of the city limits sign. 

“It gives us the opportunity to make better use of existing infrastructure, share resources where appropriate, and develop solutions that support long-term economic growth,” Fitterer said. “Ultimately, our residents and businesses care that these essential services are reliable, affordable, and capable of supporting the future. They don't necessarily care which side of a municipal boundary a solution originates on. Our responsibility as leaders is to find the best practical solutions for the people we serve.” 

WORKING TOGETHER 

Mayor Fitterer said this project means more to both cities than the mere linking of some pipes. 

“Our two cities will literally be connected through this infrastructure, but I think the more important connection is the relationship we are building between our communities and our leadership teams,” he said. “This agreement required communication, trust, and a willingness to look beyond municipal boundaries. Mayor Molder and I recognized that we had an opportunity to work together, and our staffs have worked to translate that shared vision into a practical agreement. Spring Hill is willing to partner with anyone when it comes to solving challenges and taking advantages of opportunities.” 

Massey said the project has strengthened and will continue to strengthen the cities’ relationship.  

“Columbia and Spring Hill staff have had an ongoing dialogue on this ever since we began talking about it,” he said. “Our vice mayor and two of our city councilmembers attended the Spring Hill Board of Mayor and Aldermen meeting when they approved the agreement to show our city’s support. Spring Hill representatives and their mayor attended our city council meeting when we approved it. I can’t really think of a better example of true regional partnership where two city utilities mutually benefit from an agreement. It’s a win-win for Columbia and a win-win for Spring Hill.”  

He said Columbia officials went into the project wanting to help a neighbor in need but knowing they had to consider what was best for their own citizens. 

“We had some people when we were going into this say we would have to raise sewer rates or that we would run out of capacity, and they were all wrong,” Massey said. “It was  the exact opposite. Not only do we have the capacity, this will probably keep us from having to raise sewer rates for the next couple of years. We wanted to be fair to Spring Hill, but we also had to be fair to the city of Columbia, and I think we’ve done that.” 

 Mayor Fitterer said that the project is a testament to how important relationships are between officials in neighboring jurisdictions.  

"You don't want to begin building trust for the first time when you're already facing a crisis,” Fitterer said. “Mayor Molder and I had an existing relationship and were able to have an honest conversation, recognize a potential mutual benefit, and give our staffs the opportunity to explore a solution. That kind of cooperation is much easier when there is already a foundation of communication and respect. I would also encourage municipalities to approach these discussions with an open mind. Sometimes the best solution isn't entirely within your own jurisdiction. If we are willing to focus on the problem, consider creative approaches, and work together in the best interests of our residents, we can accomplish more than we might working independently. And listen to your residents, sometimes they have the answers you're looking for.” 

Mayor Molder agreed that the project is an example of how municipal collaboration can tackle regional issues.  

“The way I look at it, Spring Hill had a need, they called, we answered the call, and we will mutually benefit as a result,” he said. “City leadership realized an opportunity to bring two needs together in a way that will benefit both communities, and I think importantly here, it demonstrates how local governments can work together to create practical solutions that serve both communities. Especially now, at a time when our region is growing and infrastructure needs are going to continue to be at the forefront. Creating regional solutions to regional problems will be a top priority for communities going forward, and I’m proud Columbia and Spring Hill were at the forefront.”