New sewer options spur rural housing, worry planning officials
The growth in areas not served by a public sewer is made possible by a new wastewater treatment method known as decentralized or “onsite” sewer systems. A Tennessee Department of Environment and Conservation report released this month estimates 183 decentralized wastewater treatment systems are serving 18,000 homes and 77,000 residents in the state.
Dr. John Buchanan, a water quality expert with the University of Tennessee Department of Biosystems Engineering and Environmental Science and director of the UT Center for Decentralized Wastewater Management, said he has heard industry figures that suggest the state may have up to 100,000 homes on decentralized sewer.
Figures gathered by The Lebanon Democrat newspaper from county planning offices, state government agencies and onsite industry insiders, show almost 6,000 homes have been built or planned in developments with onsite sewer systems in the Nashville suburbs of Williamson, Rutherford and Wilson counties.
County planning officials said finding a way to slow residential building in rural areas that lack the roads and schools to handle the growth has proven next to impossible because it is the state, not local government, that decides whether to allow an onsite sewer system to be built.
“The state approves them,” said Williamson County Planning Director Greg Langeliers. “The Tennessee Regulatory Authority issues the need and necessity letter and they also grant the service areas. They make an assumption that sewer is better than no sewer.”
Most county zoning laws predate the new systems. For example, when traditional septic tanks were the only option for sewage disposal in outlying areas, Rutherford County residential zoning regulations assumed a density of about one home per acre, Planning Director John Davis said.
But a decentralized sewer technology known as septic tank effluent pump systems, or STEP, has allowed developers to fit nearly three homes on an acre of rural land. More homes being built in rural areas outside Murfreesboro, LaVergne and Smyrna have significantly increased traffic on narrow, winding roads.
“The infrastructure issue is a problem, but it’s not something we can really address” because the county decided decades ago to rezone everything that wasn’t for commercial or industrial development as residential, Davis said. “Whether it’s (a housing development) is on a suitable road or not, we don’t have any choice in the matter.”
Wilson County Road Superintendent Steve Armistead said higher density developments along rural roads unfit to carry potentially thousands more cars may force local governments to consider new taxes, such as development fees.
He pointed to a planned subdivision of more than 40 homes just south of Cedars of Lebanon State Park that will require his department to spend $20,000 to widen the road.
“A lot of people are going out and buying up road frontage and using the STEP systems …” he said. “Therefore, we’re sitting here with 10-foot, 12-foot, 14-foot-wide narrow roads that don’t have a lot of traffic count on them at this point. The systems are creating some problems along that line, and we’re going to have to find a revenue base or some way to handle the infrastructure problem that they have created for us.”
Schools also feel the impact of the growth.
“As long as you’re sparsely populated, you can generally fit in students in various schools because people are buying five-acre plots, and they’ve got one house on it,” Wilson County Schools Director Jim Duncan said. “But, if they buy five acres, and there are five houses on it, then that changes things.”
Proponents of decentralized waste water systems contend the technology is better for the environment than conventional septic tanks, which can fail and contaminate natural water systems if not properly maintained. Federal and state government grants have encouraged the use of the onsite sewers.
TDEC gave $100,000 to UT to help establish the Center for Decentralized Wastewater Management. Buchanan, the center’s director, said it aims to train onsite system technicians and engineers and to conduct research to advance the technology.
State agencies have begun to note how the decentralized sewers have spurred residential growth.
TDEC spokesman David Owenby said the department has begun holding talks with other state regulatory bodies, namely the TRA, concerning the use of onsite technology and its implications.
———
Information from: The Lebanon Democrat