Sewer System
Brentwood’s Sewer System
- The City's sewer service district DOES NOT include all residents within the City. With a few exceptions, the City does not provide sewer services to most areas east of Edmondson Pike and Sunset Road. Please see the service area map located under Billing and Customer Service Page.
- Brentwood's sewer system is a "Collection" system-only, meaning Brentwood does not own and operate a wastewater treatment facility. Brentwood owned and operated a wastewater treatment plant until the early 80's which was located at what is now Deerwood Park.
- Since the closing of the City's wastewater plant, the City has contracted with Metro-Nashville for these treatment services.
- The sewer system consists of approximately 315 miles of sewer pipe ranging from 1-1/4" low pressure force mains to 30" gravity sewer pipe.
- There are currently 11 pumping stations located throughout the service district.
- Two sewer (drainage) basins - Little Harpeth River Basin and Owl Creek Basin
Sewer System Master Planning & Rehabilitation
The Brentwood Water Services Department (WSD) began a multimillion dollar master planning and rehabilitation project starting in 2005 with the objective to significantly reduce sewer overflows and prepare an updated, comprehensive sewer system master plan that proactively address future system capital improvements needed to meet the challenges of growth to the district's buildout boundary. Additionally, the WSD reviews its financial standing with respect to rates and new development tap fees, to ensure full cost recovery of needed capital improvements and to avoid future significant financial impacts.
Sewer System Master Plan (SSMP): In 2016, the WSD and its consultant HAZEN Engineers, developed a long-range sewer system master plan to provide the necessary guidance for City staff to address and provide for system capacity in the near term as well as for long-term system buildout. Preparation of the master plan included development of a very detailed, computer hydraulic sewer system model that is utilized for capital project projections, development project specific evaluations and use in sewer rehabilitation project evaluations. Flow monitors exist throughout the piping system and record and transmit daily flow data which is then used by the model to understand current system hydraulics and predict future capacity needs.
Currently, the WSD has constructed numerous SSMP recommended projects along with funding sewer rehabilitation efforts. Two of the more notable projects include design and construction of equalization (EQ) facilities or "storage" facilities. These storage facilities are recommended when rehabilitation efforts reach a point of diminishing returns and continued efforts to renew or rehabilitate underground piping (see below Sewer Rehabilitation program details) are ineffective. Once this point has been reached, additional storm water infiltration and inflow (I/I) can be managed by storing the excess wastewater during heavvy rain events. The tanks are designed to store a volume of wastewater that can accommodate a 2yr./24hr. storm event; or the EPA and State recommended compliance threshold. The first such EQ storage tank was completed near the campus of CPA and included a 4 million gallon tank and pumping station (See photo EQ#1 below). The second planned tank is under design and planned to be constructed in Tower Park, adjacent to the WSM tower and near the on ramp to Interstate 65. This second of two tanks is expected to break ground around the first of the year, 2027.
More detailed information related to the SSMP and two storage facilities can be found at the links below, including the full SSMP report and the project engineer's power point presentation to the Board with concept drawings of the second tank proposed within Tower Park:
Brentwood Sewer System Master Plan(PDF, 4MB)
Hazen presentation to Board of Commissioners(PDF, 2MB)
Sewer System Rehabilitation: Sewer rehabilitation, which plays a significant role in master planning, consists of evaluating the sewer system infrastructure and restoring aging or damaged system facilities (underground pipeline, pumping stations, etc.) to extend their service life. Most rehabilitation methods, such as cured in place pipelining and manhole lining, are used in place of new replacement as a cost-effective alternative. The focus of sewer rehabilitation is areas with the greatest infiltration and inflow or "I/I". I/I is extraneous storm water that enters the sewer system through cracks and openings in underground pipe and takes up the needed capacity, predominantly during storm events. In more recent decades, EPA and the State have placed a strong emphasis on utilities reducing the I/I in sewer systems to aid in the prevention of overflows. The City began an aggressive rehabilitation program in 2007 and has successfully achieved: reduced the measured volume of I/I entering the system by over 1.5 million gallons per day; rehabilitated over 20% of system infrastructure in the LHR basin; reductions in overflows by 90%; WSD awarded the "Rehabilitation Program of the Year" for the KY and TN region; WSD and SSR Engineers awarded the 2025 ACEC Engineering Excellence Award for the EQ Facility #1; and all regulatory compliance matters satisfactory completed and released. Sewer rehabilitation will always be an important function of system operations and will be funded at some level annually.
EQ#1 Tank, Old Hickory Blvd. CONCEPT - EQ Tank #2 at Tower Park