We analyzed infrastructure data from Metro Nashville Water Services, the U.S. Census Bureau, and EPA compliance reports to answer a key question: Is Nashville’s underground sewer and water system keeping pace with its explosive growth?
Our review of Davidson County population trends (2020–2024), 6,000+ miles of underground pipe age data, repair rates, and the $2.5 billion Clean Water Nashville EPA Consent Decree reveals a widening gap between Nashville’s rapid population boom and its aging infrastructure’s ability to keep up.
12 KEY FINDINGS
A Growing City on Aging Pipes
Nashville is experiencing steady population growth, with Davidson County adding an average of 867 new residents each month in 2024. This surge in newcomers is placing increasing pressure on the city's aging sewer infrastructure. More than half of Nashville's 6,000 miles of sewer and water pipes are over 40 years old, many of them installed decades ago when the city was far smaller and the system was not designed to handle today's demand.
BACKGROUND
Nashville has earned national recognition as one of America’s fastest-growing cities, attracting new residents with its thriving music industry, affordable cost of living compared to coastal cities, and booming healthcare and technology sectors. However, beneath the surface of this growth boom lies a less visible challenge: the city’s underground infrastructure was built for a much smaller population.
Metro Nashville Water Services operates one of the oldest continuously-running water systems in the United States, with components dating back to the 1800s. While the system has been expanded and maintained over the decades, the rate of population growth in recent years has begun to outpace infrastructure improvements.
RESULTS
According to U.S. Census Bureau estimates, Davidson County added 10,413 new residents between July 2023 and July 2024. This translates to an average of 867 new residents every month, or approximately 29 new people every single day.
During the same period, Metro Nashville Water Services replaces approximately 20 miles of aging water mains annually through its infrastructure rehabilitation program. Meanwhile, Metro Water Services rate documentation confirms that more than 50% of the city’s water and sewer pipes are over 40 years old — well into the second half of their typical 50-100 year lifespan.
CONTEXT
The mathematics of this situation present a significant challenge for Nashville’s long-term infrastructure sustainability. While adding 867 residents monthly represents healthy economic growth, it also means 867 more people depend on an underground pipe network where aging components outnumber replacement efforts.
Industry standards suggest water and sewer pipes should be replaced before reaching 75-100 years of age, depending on the pipe material. Cast iron pipes, common in older sections of Nashville, typically last 75-100 years. Clay pipes, also prevalent in mid-century construction, have a 50-60 year lifespan. PVC pipes installed in more recent decades can last 100+ years but still require eventual replacement.
For Davidson County homeowners, this means the risk of sewer line failures will likely increase in coming years as pipes installed in the 1960s-1980s reach the end of their service life. Neighborhoods built during Nashville’s mid-century expansion — including areas of Madison, Donelson, and Antioch — may be particularly vulnerable as large numbers of homes face simultaneous infrastructure aging.
Davidson County's Largest Population Jump Since 2015
Davidson County saw a significant population increase in 2024, gaining 10,413 new residents between July 2023 and July 2024 - marking the largest single-year growth for the county since 2015. This rapid influx reflects the area's strong economic momentum and growing appeal as a place to live and work.
BACKGROUND
Population growth data provides a crucial benchmark for infrastructure planning. Cities typically use multi-year population trends to project future needs and budget for system expansions or replacements. The challenge arises when growth accelerates faster than infrastructure improvement timelines can adapt.
The 2024 increase marked a significant shift from recent years. From 2016 to 2022, neighboring Rutherford County consistently added more residents than Davidson County. However, revised Census Bureau methodology — particularly in how international migration is calculated — revealed that Davidson County has once again become one of Tennessee’s fastest-growing counties.
RESULTS
The Tennessee State Data Center reported that Davidson County’s 10,413-resident increase in 2024 (measured July 2023 to July 2024) represents the largest year-over-year population increase the county has experienced since 2015, when Davidson County last topped the state’s population growth rankings.
CONTEXT
This population surge creates a compounding infrastructure challenge. Each new resident doesn’t just add to the total number of people the system must serve — they also contribute additional wastewater flow, increased water demand during peak usage times, and greater stress on aging pipes that may already be operating near capacity.
Metro Water Services serves approximately 660,000 customer accounts (representing households and businesses) across Davidson County, serving water to roughly 660,000 people and wastewater services to approximately 750,000 people in the service area. The addition of 10,413 residents in a single year represents a 1.6% increase in the population that depends on the same underground infrastructure.
For context, if Davidson County continues adding residents at this pace, the system will need to serve an additional 104,000+ people over the next decade — equivalent to adding a city the size of Franklin, Tennessee to the existing infrastructure.
Nashville Metro: 136,000 New Residents in Four Years
Since 2020, the Nashville metropolitan area — which includes Davidson, Williamson, Rutherford, Sumner, Wilson, and several other surrounding counties — has welcomed approximately 136,000 new residents. This represents a remarkable 6.4% population increase across the multi-county region in just four years, reflecting the area's strong economy, cultural vibrancy, and continued appeal as one of the nation's top destinations for relocation.
BACKGROUND
The 2020-2024 period presented unique challenges for cities nationwide. The COVID-19 pandemic initially slowed migration patterns, but many mid-sized metropolitan areas like Nashville experienced accelerated growth starting in 2021 as remote work options enabled people to relocate from higher-cost metropolitan areas.
The Nashville region benefited from several migration trends during this period. The absence of state income tax in Tennessee made the region attractive to professionals seeking to maximize take-home pay. The city’s growing reputation as a technology hub — often called “Silicon Hills” — drew tech workers. Additionally, Nashville’s relatively affordable housing compared to coastal cities appealed to first-time homebuyers and young families.
RESULTS
U.S. Census Bureau population estimates show the Nashville metropolitan area has grown by 136,000 residents from 2020 to 2024. This represents a 6.4% population increase in just four years, significantly outpacing the national growth rate of 3% during the same period.
The Nashville metro area population stood at approximately 2.13 million residents in 2020. By 2024, that figure had climbed to 2.27 million — adding more people than the entire population of cities like Charleston, South Carolina or Savannah, Georgia.
CONTEXT
A 6.4% population increase in four years would strain any regional infrastructure system, but the impact is particularly pronounced for underground utilities that require years of planning and construction to expand or replace.
Unlike above-ground infrastructure that can be quickly modified or expanded, sewer and water systems require extensive engineering, permitting, and coordination with other underground utilities. Replacing a single mile of water main can take months and cost $400,000 to $1 million depending on the diameter of the pipe and complexity of the installation.
While this regional growth is distributed across multiple counties, Davidson County — as the urban core — bears a disproportionate infrastructure burden. The Clean Water Nashville program, initiated under a 2009 EPA Consent Decree, was originally designed based on population projections that predated this recent growth surge. The faster-than-expected population increase means Davidson County’s system is now serving more people than some infrastructure improvement plans anticipated.
An International City on an Aging Foundation
International migration has contributed to Nashville's growth in recent years. According to Census Bureau data analyzed by the Tennessee State Data Center, Davidson County experienced net international migration of 8,879 people in 2024—the highest single-year total for the county in the current decade. This reflects both Nashville's appeal as a welcoming immigrant gateway city and revised Census Bureau methodology that better captures international migration patterns.
BACKGROUND
Nashville has a long history as an immigrant gateway city. The city gained national attention in the mid-2000s as a successful model for immigrant integration, with former President Obama visiting Nashville in 2014 to discuss the economic contributions of the immigrant community. The city’s foreign-born population has more than doubled since 2000, creating diverse neighborhoods and supporting economic sectors including healthcare, construction, and hospitality.
The Census Bureau significantly revised its international migration estimation methodology in 2024 to better capture migration patterns affected by events like COVID-19, changes in immigration policy, and increased migration flows. This methodological update resulted in substantial upward revisions to international migration figures for 2022-2024 across the country, with urban counties like Davidson receiving larger adjustments to reflect actual population movements more accurately.
RESULTS
Davidson County’s international migration figures have increased significantly in recent years, with 8,879 net international migrants in 2024 alone according to the Tennessee State Data Center. This represents the county’s highest single-year international migration total in the current decade.
The elevated international migration figures primarily reflect the Census Bureau’s improved methodology for capturing actual migration patterns, which incorporates additional data sources beyond previous estimation methods. Davidson County, as Tennessee’s largest urban center and a recognized immigrant gateway city, naturally captures a significant share of the state’s international migration.
CONTEXT
International migration creates unique infrastructure considerations. New arrivals often settle in established neighborhoods with existing housing stock rather than newly developed areas. This means international growth adds population density to neighborhoods where infrastructure may already be decades old.
Areas of Nashville with historically high immigrant populations — including sections of South Nashville, Antioch, and Nolensville Pike corridor — frequently have housing stock built in the 1960s-1980s. These neighborhoods are now supporting more residents than originally intended, placing additional stress on sewer lines installed 40-60 years ago.
For sewer systems, higher population density in existing neighborhoods increases wastewater flow through pipes designed for smaller households. While modern water efficiency standards mean individual water usage per person has decreased, the total flow through neighborhood collection systems increases with population density.
More Than Half of Nashville's Pipes Exceed 40 Years Old
More than half of Nashville's water and sewer pipes are now over 40 years old, forming an aging network that underpins the entire city's daily life. Many of these components were installed long before modern standards for infrastructure design and capacity.
BACKGROUND
Nashville’s water system has been in continuous operation since 1831, making it one of the oldest municipal water systems in the United States. The system expanded significantly in the late 1800s and early 1900s as Nashville grew into a regional hub for commerce and industry.
Different eras of construction used different pipe materials, each with varying lifespans. Early systems used cast iron and clay pipes. Mid-century expansion (1950s-1980s) relied heavily on clay sewer pipes and cast iron water mains. Modern construction uses ductile iron for water mains and PVC for sewer systems.
The mix of pipe ages and materials across Nashville’s system creates a patchwork of infrastructure in various stages of its lifecycle. Some sections have been replaced or rehabilitated in recent decades, while others remain largely unchanged since original installation.
RESULTS
Metro Nashville Water Services documentation confirms that more than 50% of the city’s water and sewer pipes are over 40 years old. The utility operates approximately 3,000 miles of water mains and 3,000 miles of sewer pipes across Davidson County. The water system serves 660,000+ customer accounts while the wastewater system serves approximately 750,000 people in the service area.
The system also includes historical infrastructure components. According to Metro Water Services, portions of the system include pipes and facilities from the late 1800s, though these represent a small fraction of the overall network and have undergone significant upgrades over the decades to meet modern standards.
CONTEXT
The statistic that more than 50% of pipes exceed 40 years of age is particularly significant because it indicates that a large portion of the system is approaching the midpoint or latter stages of expected service life. For clay sewer pipes with 50-60 year lifespans, a 40-year-old pipe is nearing replacement age. For cast iron water mains with 75-100 year lifespans, 40 years represents the midpoint where maintenance needs typically increase.
Homeowners in Nashville neighborhoods built during the 1960s-1980s construction boom should be aware that their home’s sewer lateral line — the pipe connecting the house to the main sewer line in the street — is likely approaching the same age as the municipal infrastructure. Property owners are responsible for maintaining and repairing their lateral line, meaning that as the public system ages, private lines are aging simultaneously.
6,000 Miles of Underground Infrastructure
Nashville operates an extensive and complex underground infrastructure network spanning more than 6,000 miles of pipes — including over 3,000 miles of water mains and another 3,000 miles of sewer lines. This vast system delivers essential services to Davidson County's growing population, supplying clean water and managing wastewater across the region.
RESULTS
Metro Nashville Water Services maintains more than 6,000 miles of underground pipes across Davidson County, split roughly evenly between water distribution and wastewater collection. The system includes:
- 3,000+ miles of water mains
- 3,000+ miles of sewer pipes
- 37 water storage reservoirs
- 56 water pumping plants
- 3 wastewater treatment plants.
This infrastructure serves approximately 660,000 customer accounts and operates 24 hours a day, 365 days a year, moving drinking water to residents and businesses while collecting and treating wastewater to protect the Cumberland River and its tributaries.
CONTEXT
To visualize the scale of Nashville’s underground infrastructure: 6,000 miles of pipe would stretch from Nashville to London, England and back. If laid end-to-end, the pipes would circle the Earth’s equator nearly one-quarter of the way around.
This extensive network requires constant monitoring, maintenance, and eventual replacement. Even under ideal circumstances with unlimited funding, replacing or rehabilitating a system of this size would take decades. The current replacement rate of 20 miles annually represents just 0.33% of the total system being updated each year.
The complexity of Nashville’s infrastructure is increased by the city’s hilly topography. Unlike flat cities where gravity can move water and wastewater naturally, Nashville requires 56 pumping stations to move drinking water to various elevation zones across the area. On the wastewater side, the terrain creates challenges for maintaining consistent flow in sewer lines, as pipes must navigate steep elevation changes.
For residents, this invisible underground network is easy to take for granted until service is disrupted. News reports from 2024-2025 documented multiple water main breaks across Nashville during extreme weather events. These incidents highlight the ongoing challenge of maintaining aging infrastructure while serving a growing population.
300 Years to Catch Up
At the city's current pace of replacing just 20 miles of pipe each year, fully renewing Nashville's 6,000-mile underground network would take approximately 300 years. This mathematical reality highlights the fundamental challenge facing Nashville and cities across America: infrastructure needs far outpace available replacement resources.
BACKGROUND
Infrastructure replacement rates are typically measured as the percentage of the system replaced annually. A 1% annual replacement rate is often considered a minimum standard for maintaining system integrity, which would mean replacing 60 miles of pipe per year for a 6,000-mile network.
However, infrastructure replacement must compete for funding with other city priorities including schools, public safety, parks, and road maintenance. Additionally, the cost of pipe replacement has increased significantly in recent decades due to rising material costs, labor expenses, and more stringent environmental and safety requirements during construction.
Metro Nashville Water Services is an enterprise fund, meaning it receives no tax revenue and must fund all operations, maintenance, and capital improvements through water and sewer rates charged to customers. This creates a direct tension between keeping rates affordable for residents and generating sufficient revenue for infrastructure replacement.
RESULTS
Metro Nashville Water Services replaces approximately 20 miles of aging infrastructure annually through its rehabilitation program. At this rate, mathematically replacing the entire 6,000-mile network would take 300 years.
The annual replacement program doesn’t operate on a simple sequential schedule. Instead, Metro Water prioritizes pipes based on several factors including leak history, water quality concerns, age of the infrastructure, coordination with road projects, and risk assessment to maximize the impact of limited resources.
CONTEXT
The 300-year calculation illustrates the scale of the challenge rather than representing an actual replacement timeline. In practice, utilities prioritize the most critical infrastructure — focusing on pipes with the highest failure rates, those serving the most customers, and those requiring replacement to meet safety and environmental standards.
However, this approach creates a risk: pipes in lower-priority areas may continue aging beyond their design life, potentially leading to increased failures. Since pipe lifespans range from 50-100 years depending on material, significant portions of the system will reach the end of their service life long before replacement occurs under current funding levels.
The American Society of Civil Engineers estimated that Tennessee needs $8.7 billion over 20 years to maintain and improve drinking water infrastructure statewide. With Nashville representing a significant portion of Tennessee’s population, the region’s share of this need would be substantial.
For homeowners and businesses, the implication is that sewer and water service reliability may vary across neighborhoods based on infrastructure age and condition. Property owners in areas with 50+ year old infrastructure should consider having their private sewer lateral lines inspected, as these property-owner-maintained pipes are aging on the same timeline as the public system.
The $2.5 Billion Challenge
Nashville is confronting a massive infrastructure investment under the Clean Water Nashville EPA Consent Decree program — a long-term initiative required to bring the city's aging sewer systems into compliance with federal environmental standards. The program, now estimated at $2.5 billion and financed over multiple decades through gradual rate increases, represents one of the largest infrastructure investments in Nashville's history.
BACKGROUND
The Clean Water Nashville program addresses violations of the Clean Water Act related to combined sewer overflows (CSOs) and sanitary sewer overflows (SSOs). Combined sewers — which carry both sanitary sewage and stormwater in the same pipe — can overflow during heavy rainfall events, discharging untreated sewage into the Cumberland River.
The EPA and Tennessee Department of Environment and Conservation negotiated the 2009 Consent Decree requiring Nashville to eliminate or significantly reduce these overflows. The decree mandates specific improvements on a defined timeline, with penalties for non-compliance.
Nashville is not alone in facing this challenge. Many older American cities built combined sewer systems in the early-to-mid 1900s. Cities including Atlanta, Cincinnati, and Philadelphia are implementing similar multi-billion dollar programs under EPA Consent Decrees.
RESULTS
Nashville is currently implementing the Clean Water Nashville Overflow Abatement Program, a comprehensive sewer system improvement initiative required under a 2009 EPA Consent Decree. The program, initially budgeted at $1.5 billion, has grown to an estimated $2.5 billion according to program management documentation.
The program is funded entirely through water and sewer rates rather than property taxes, with costs distributed over the multi-decade implementation period. Metro Water Services implemented rate increases from 2020-2024 to fund the improvements, with additional adjustments planned for future years as work continues.
CONTEXT
The $2.5 billion investment, while substantial, represents the cost of modernizing Nashville’s sewer infrastructure to protect public health and water quality over a 20+ year timeframe. For comparison, the city’s entire annual operating budget across all departments is approximately $3 billion.
The program includes projects such as:
- Installing larger capacity sewer pipes to reduce overflows
- Separating combined sewers into separate sanitary and storm systems
- Rehabilitating aging sewer lines using trenchless technology
- Upgrading treatment plant capacity
- Installing storage tunnels to capture overflow during storms.
With Davidson County’s 2024 population of approximately 660,000 residents, the total program cost translates to roughly $3,788 per resident when viewed as a one-time figure. However, this doesn’t reflect how costs are actually distributed. Individual ratepayer impact depends on water usage, property type (residential vs. commercial), and the extended financing timeline that spreads costs over decades through modest annual rate adjustments.
For homeowners, the positive aspect of this massive investment is that significant portions of Nashville’s sewer system are being upgraded to modern standards. However, the Clean Water Nashville program primarily addresses the public sewer system. Private lateral lines — the pipes connecting individual properties to the main sewer line — remain the homeowner’s responsibility to maintain and repair.
Homeowner Sewer Line Repairs: $3,000-$15,000
For Nashville homeowners, repairing damaged sewer lines can come with a steep price tag. A typical 50-foot section of damaged pipe can cost anywhere from $3,000 to $15,000 to repair using traditional excavation methods — expenses that fall directly on property owners, not the city.
BACKGROUND
Most homeowners don’t realize they’re responsible for maintaining the sewer lateral line connecting their home to the municipal sewer main in the street. This private portion of the sewer system — typically 40-100 feet depending on the property — belongs to the homeowner, not the city.
When this line fails due to age, tree root intrusion, or ground settlement, homeowners must pay for repairs or replacement. Most homeowners insurance policies don’t cover sewer line failures unless specifically added as optional coverage.
Common warning signs of sewer line problems include frequent drain backups, gurgling sounds from plumbing fixtures, sewage odors in the home or yard, and slow drainage across multiple fixtures simultaneously. Many homeowners mistake these symptoms for simple clogs and don’t realize the lateral line itself has failed until a plumber performs a video camera inspection.
RESULTS
Homeowners facing sewer line failure typically encounter repair costs ranging from $3,000 to $15,000 for replacing 50 feet of damaged pipe, according to industry cost surveys. The wide cost range reflects factors including:
- Pipe depth and accessibility
- Soil conditions and site complexity
- Whether traditional excavation or trenchless methods are used
- Regional labor rates and permit fees
- Length of pipe requiring replacement.
Traditional excavation methods cost approximately $50-$250 per linear foot depending on these variables. For a typical residential sewer lateral line of 50 feet (the average distance from a house to the street connection), total costs can quickly escalate into five figures.
CONTEXT
The cost burden of sewer line replacement falls entirely on the property owner at a time when many Nashville homeowners are already facing higher housing costs. With the median home construction year in Davidson County at 1983, a large portion of Nashville’s housing stock has sewer lateral lines that are 40+ years old and approaching typical failure points.
For context, a $3,000-$15,000 unexpected repair expense represents a significant financial hardship for many families. According to Federal Reserve data, approximately 37% of American adults would struggle to cover an unexpected $400 expense without borrowing money or selling possessions. A sewer line failure can easily cost 10-37 times that amount.
The financial impact is particularly acute in historically affordable Nashville neighborhoods where home values have risen rapidly in recent years. Long-time residents who purchased homes decades ago may not have planned for major infrastructure repairs, while newer buyers who paid premium prices may have limited savings after making their down payment.
Trenchless repair technologies offer a potential cost-saving alternative in some situations. Methods like cured-in-place pipe (CIPP) lining can rehabilitate existing pipes without extensive excavation, reducing both direct costs and the expense of landscaping restoration. However, trenchless methods aren’t suitable for all types of damage, and homeowners should obtain multiple quotes and seek expert guidance on the best approach for their specific situation.
Half of Nashville Homes Built Before 1983
The median year of home construction in Davidson County is 1983, which means that half of all homes in Nashville are now more than 42 years old. Many of these properties still rely on original sewer lines that are nearing or have already reached the end of their expected lifespan. This is particularly true in neighborhoods developed during the 1960s and 1970s, where aging pipes are increasingly susceptible to cracks, blockages, and failures.
BACKGROUND
Sewer lateral lines typically match the age of the home’s original construction. When builders constructed homes in the 1960s-1980s, they installed sewer laterals using the common pipe materials of that era — primarily clay or cast iron.
Clay sewer pipes have a typical service life of 50-60 years. Cast iron pipes last 75-100 years. This means sewer lines installed in the 1960s and 1970s are now approaching or have exceeded their expected lifespan. Even pipes from the 1980s are entering the latter half of their service life.
Several factors can accelerate pipe deterioration:
- Tree root intrusion (a leading cause of sewer line failure)
- Soil conditions and ground shifting
- Improper installation or inadequate slope
- Chemical reactions from cleaning products
- Ground freezing and thawing cycles.
RESULTS
The median home construction year in Davidson County is 1983, according to housing demographics data. This means 50% of homes in the county were built before 1983, making them 42+ years old as of 2025. Breaking down the age distribution:
- 5.8% of homes were built before 1940
- 3.2% were built in the 1940s
- Significant expansion occurred from 1950-1989
- Each decade from 1950-2010 accounts for at least 10% of current housing stock.
Neighborhoods built during Nashville’s mid-century boom period, particularly the 1960s-1970s, represent a large portion of Davidson County’s housing inventory.
CONTEXT
The concentration of pre-1983 homes creates a potential wave of sewer lateral line failures in the coming 10-20 years as pipes installed 40-60 years ago reach the end of their service life. This isn’t a hypothetical future problem — it’s already beginning, as evidenced by the growing market for sewer line repair and replacement services.
Neighborhoods particularly affected by aging infrastructure include:
- Donelson (major expansion in 1960s-1970s with ranch-style homes)
- Madison (post-WWII growth)
- Antioch (1970s-1980s development)
- Sections of East Nashville (mix of pre-WWII and mid-century housing)
- West Nashville suburbs built in 1960s-1970s.
For prospective home buyers in Nashville, home age should be a consideration when budgeting for long-term ownership costs. A standard home inspection may reveal the condition of visible plumbing, but most inspections don’t include sewer camera inspection. Buyers purchasing homes built before 1985 should consider requesting a sewer line video inspection to assess the condition of this hidden but expensive-to-repair component.
Current homeowners in older properties might consider proactive sewer line inspection, especially if they’ve experienced slow drains, frequent clogs, or notice other warning signs. Identifying problems early can sometimes allow for less extensive repairs before complete line failure occurs.
Tennessee's $8.7 Billion Infrastructure Need
Tennessee faces a substantial challenge in maintaining and upgrading its drinking water infrastructure. According to the American Society of Civil Engineers, the state will require $8.7 billion over the next 20 years to ensure that water systems remain safe, reliable, and capable of meeting future demand. This figure reflects the widespread need to replace aging pipes, modernize treatment facilities, and expand capacity to accommodate ongoing population growth.
BACKGROUND
The American Society of Civil Engineers (ASCE) publishes regular “Infrastructure Report Cards” assessing the condition and investment needs of various infrastructure categories across the United States. These reports evaluate drinking water, wastewater, roads, bridges, and other critical systems.
Water infrastructure typically requires sustained investment over decades rather than one-time expenditures. As systems age, maintenance costs increase even before replacement becomes necessary. Deferred maintenance often results in higher long-term costs as small problems develop into major failures.
The $8.7 billion Tennessee estimate includes needs for:
- Water main replacement in aging systems
- Treatment plant upgrades to meet evolving regulations
- Lead pipe removal (required by EPA rules)
- System expansion to serve growing areas
- Maintenance and rehabilitation of existing infrastructure.
RESULTS
The American Society of Civil Engineers estimates that Tennessee needs $8.7 billion over the next 20 years to maintain and improve drinking water infrastructure statewide. This figure represents the gap between projected infrastructure needs and currently allocated funding.
The estimate has been cited in infrastructure coverage by Tennessee media outlets during reports on water main breaks affecting Middle Tennessee communities. Local engineers have emphasized that infrastructure investments can’t be delayed without risking more frequent failures and service disruptions.
CONTEXT
With Tennessee’s population of approximately 7.1 million, the $8.7 billion need translates to roughly $1,225 per resident over 20 years, or about $61 per person annually. However, infrastructure costs aren’t distributed evenly across the state. Older urban systems like Nashville typically require more investment than newer suburban systems.
As Tennessee’s largest metropolitan area, Nashville accounts for a significant share of both the state’s population and its aging infrastructure. While precise allocation of the $8.7 billion figure isn’t publicly broken down by region, Middle Tennessee’s combination of old infrastructure and rapid growth likely places it among the highest-need areas statewide.
The funding gap represents the difference between what’s needed and what current revenue streams can support. Closing this gap requires some combination of:
- Higher water and sewer rates
- State or federal infrastructure grants
- Improved efficiency in infrastructure management
New - technologies that reduce replacement costs.
For Nashville-area residents, the implication is that water and sewer rates will likely continue increasing over coming decades as Metro Water Services works to address aging infrastructure while serving a growing population. The alternative — deferring necessary improvements — would result in more frequent service disruptions, water quality concerns, and eventual system failures that would be even more expensive to address.
The Rise of Trenchless Technology
The trenchless technology market is experiencing steady growth, expanding at an annual rate of 6-7% and projected to surpass $8.4 billion by 2030. This growth reflects a shift toward innovative, minimally invasive methods for repairing and replacing underground utilities — methods that can save homeowners thousands of dollars in landscaping restoration costs.
BACKGROUND
Trenchless technology refers to methods of repairing or replacing underground pipes with minimal excavation. Instead of digging a continuous trench to access the entire length of pipe — the traditional method — trenchless approaches typically require only small access points at each end of the repair section.
Common trenchless methods include:
- Cured-In-Place Pipe (CIPP): A flexible liner saturated with resin is inserted into the existing pipe and inflated. Once cured, it forms a new pipe inside the old one, sealing cracks and preventing root intrusion.
- Pipe Bursting: A new pipe is pulled through the old pipe while simultaneously breaking apart the old pipe and pushing fragments into the surrounding soil.
- Slip Lining: A smaller diameter pipe is inserted inside the existing pipe to create a new flow path.
These methods gained prominence starting in the 1990s and have become increasingly sophisticated and cost-effective over time.
RESULTS
The global trenchless pipe rehabilitation market is projected to grow from $6.0 billion in 2023 to $8.4 billion by 2030, representing a compound annual growth rate (CAGR) of 4.6-7.2% depending on the specific market segment and region analyzed.
Multiple industry research reports confirm this growth trajectory:
- Trenchless pipe relining market expected to reach $8.4 billion by 2030
- Trenchless equipment market growing at 5.8% CAGR
- North America represents the largest regional market at approximately 35-38% of global revenue
- Cured-in-place pipe (CIPP) technology accounts for 35-44% of trenchless installations.
CONTEXT
The growth in trenchless technology adoption reflects several converging factors that are particularly relevant to Nashville homeowners:
- Reduced Property Disruption: Traditional sewer line replacement requires digging a trench across the property from the house to the street, destroying landscaping, driveways, sidewalks, and sometimes portions of home foundations or patios. Trenchless methods preserve yards and hardscaping, eliminating thousands of dollars in restoration costs.
- Faster Completion: Trenchless repairs often take 1-2 days compared to 5-7 days for traditional excavation, reducing disruption to the household and minimizing time without sewer service.
- Lower Total Cost: While trenchless methods may have higher per-foot installation costs, the total project cost is often lower when accounting for reduced excavation, faster completion, and elimination of landscape restoration expenses.
- Aging Infrastructure: The United States has more than 800,000 miles of public sewer pipes, many installed 50-100 years ago. As this infrastructure ages, demand for repair solutions grows proportionally.
For Nashville-area homeowners dealing with aging sewer lateral lines, trenchless technology offers a viable alternative to traditional replacement. However, not all situations are suitable for trenchless repair. Pipes that have completely collapsed, are severely misaligned, or have extensive root intrusion may still require excavation.
Property owners facing sewer line issues should consult with contractors experienced in both traditional and trenchless methods to determine the best approach for their specific situation. Video camera inspection — available from specialized plumbing companies — can assess pipe condition and help identify whether trenchless repair is feasible.
What This Means for Nashville Homeowners
Nashville's infrastructure challenge presents a clear picture: a rapidly growing city dependent on an aging underground system that's being replaced far slower than it's deteriorating. While Metro Water Services works to address the most critical infrastructure needs through programs like Clean Water Nashville, individual homeowners bear responsibility for their own sewer lateral lines.
The data suggests that thousands of Nashville homeowners — particularly those in homes built before 1985 — may face sewer line repairs in the coming decade as pipes reach the end of their 50-60 year service life. Proactive inspection and maintenance can help identify problems early, potentially reducing repair costs and avoiding emergency situations.
For homeowners concerned about their sewer infrastructure, several steps can help manage risk:
- Know your home's age: Homes built before 1985 are most at risk for sewer line failure
- Watch for warning signs: Slow drains, gurgling sounds, sewage odors, or frequent backups
- Consider camera inspection: A professional sewer camera inspection costs $200-400 and can identify problems before they become emergencie
- Explore insurance options: Some insurers offer sewer line coverage as an add-on policy
- Research repair methods: Understand both traditional excavation and trenchless options before you need them
CONCLUSION
This analysis is based on publicly available government data from Metro Nashville Water Services, the U.S. Census Bureau, Tennessee State Data Center, EPA Consent Decree documents, and infrastructure reports from 2024-2025. For a detailed explanation of our research methodology, data sources, and calculations, view our complete source documentation and methodology notes.
The data reveals a significant and growing gap between Nashville's population boom and the pace of underground infrastructure maintenance. While the city's growth represents economic vitality and opportunity, it also creates infrastructure challenges that will require sustained investment and strategic planning to address.
Now over to you: If you're a Nashville homeowner, how old is your home? Have you experienced any sewer line issues, or are you worried about aging infrastructure in your neighborhood? Share your experience in the comments below.
ABOUT THIS RESEARCH
Data Collection Period: October 2025
Primary Sources:
- U.S. Census Bureau Population Estimates Program
- Tennessee State Data Center (University of Tennessee Boyd Center)
- Metro Nashville Water Services official documentation
- Clean Water Nashville EPA Consent Decree program documents
- American Society of Civil Engineers Infrastructure Reports
- Industry cost surveys (HomeGuide, CostHelper, multiple sources)
- Trenchless technology market research reports (2024-2025)
Analysis Note: All statistics represent data available as of publication. Population figures use official Census Bureau estimates. Infrastructure age data comes from Metro Nashville Water Services public documentation. Cost estimates reflect industry averages and may vary based on specific circumstances.