Knoxville Water Hardness & Quality Report (2026)
Water Hardness
~120–179 mg/L
Hardestimated · not lab-verified
Source
reservoir
pH Level
8.1
neutral = 7.0
Lead
0.006 mg/L
✓ Below action level
TDS
359.4 mg/L
Est. Daily Cost
$0.40
energy & soap waste
Source: See methodology section below · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Knoxville, your appliances are currently losing 20% efficiency due to mineral buildup.
| Appliance | In Knoxville | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.8 yrs | 8.5 yrs | -20% |
| Washing Machine | 9.6 yrs | 12 yrs | -20% |
| Water Heater | 12 yrs | 15 yrs | -20% |
Regional Water Comparison
How Knoxville compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Knoxville, Tennessee | ≈ 120–179 mg/L | 3.7 ppt | 🟠 Hard | reservoir |
| Seymour, Tennessee | ≈ 120–179 mg/L | 7.6 ppt | 🟠 Hard | reservoir |
| Maryville, Tennessee | 46 mg/L | 0 ppt | 🟢 Soft | reservoir |
| Farragut, Tennessee | ≈ 120–179 mg/L | 5.2 ppt | 🟠 Hard | reservoir |
| Clinton, Tennessee | ≈ 120–179 mg/L | 4 ppt | 🟠 Hard | reservoir |
National Benchmark
How Knoxville compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Knoxville | ≈ 120–179 mg/L | 🟠 Moderate |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes Knoxville's Water Unique?
Local geology and source profile
Knoxville Utilities Board (KUB) provides water services to Knoxville and surrounding Knox County areas in East Tennessee. The primary sources are the Tennessee River and Holston River, with water treated at facilities including the Forks Reservoir Water Treatment Plant and Santeetlah Water Treatment Plant. KUB serves over 200,000 customers across a 1,300-square-mile service area centered in the Appalachian watershed, drawing from one of the nation's most abundant surface water supplies. Treatment involves conventional processes: coagulation, sedimentation, filtration, and disinfection using chloramines.
The Tennessee Valley watershed, encompassing the confluence of the Tennessee and Holston Rivers, is shaped by the geology of the Appalachian Mountain region. Underlying rock formations include ancient limestone and dolomite from Paleozoic eras—spanning the Ordovician to Mississippian periods—including the Knox Group and Chattanooga Shale, which are rich in calcium and magnesium. This karst landscape and mineral-rich runoff from the surrounding valleys create a moderately hard supply with elevated calcium and magnesium content.
Moderately hard water in Knoxville leads to moderate scale buildup in water heaters, dishwashers, and washing machines, reducing efficiency and increasing energy costs over time. Plumbing fixtures and faucets may show visible deposits, while laundry and dishwashing require more detergent. Regular descaling and scale inhibitors are advised; a whole-home water softener is often recommended to extend appliance life and improve soap performance. KUB maintains strong compliance with EPA standards, though health guidelines flag concerns with contaminants like PFAS and lead; annual Consumer Confidence Reports are available on KUB's site for detailed testing data.
Geology & Source: Tennessee and Holston Rivers — Paleozoic limestone and dolomite, Ordovician to Mississippian; Knox Group and Chattanooga Shale rich in calcium and magnesium; East Tennessee karst topography produces moderately hard water
Other Tennessee Water Reports
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Frequently Asked Questions
Is Knoxville's water safe to drink?
Do I need a water softener in Knoxville?
How does Knoxville compare to the USA average?
Data Sources & Methodology
Water quality data for Knoxville is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.
Water Hardness
Modelled estimate based on state-level USGS geological survey data for this region. No direct USGS Water Quality Portal measurement was matched to this city — the value reflects a statistical range calibrated to the state's dominant rock types and typical source water characteristics.
pH
Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.
TDS — Total Dissolved Solids
Estimated using a derived ratio from water hardness and regional conductance profiles. TDS in natural water correlates strongly with total mineral content including hardness ions.
PFAS — Perfluoroalkyl and Polyfluoroalkyl Substances
EPA UCMR5 (5th Unregulated Contaminant Monitoring Rule, 2023–2025) — sum of PFAS compounds detected at the public water system serving this city. A value of 0 indicates the system was sampled with no detection above reporting limits.
Lead
Modelled estimate based on the EPA Lead and Copper Rule 90th-percentile tap-sample methodology. No publicly available per-city lead dataset with sufficient national coverage exists. Values are a conservative baseline derived from city population tier and infrastructure age — all estimates are maintained below the EPA action level of 0.015 mg/L.
Appliance Lifespan
Calculated from water hardness using a linear degradation model. Baseline lifespans represent soft-water performance (kettle: 8.5 yrs, washing machine: 12.0 yrs, water heater: 15.0 yrs). Hard water mineral scale progressively reduces operational life in direct proportion to hardness concentration.