Knoxville water is 91 mg/L hard, shaded river-bottom homes grow mildew and biological film, and kudzu and ivy reach the glazing on old masonry.
Knoxville's water is moderately hard: the low end leaves almost nothing on a warm pane, while the top of the range will spot if left to dry. Shaded river-bottom homes grow mildew and biological film, and kudzu and ivy reach glass on old masonry; June and August to October are the best months. Football weekends and term dates drive predictable demand spikes, and a single-story exterior runs $240 to $430.
Knoxville Utilities Board publishes a band rather than a point, 60 to 120 mg/L, and calls its own water moderately hard. For glass that span matters more than the midpoint: the bottom of it leaves almost nothing behind on a warm pane, while the top will spot visibly if a sunny elevation is allowed to flash off before the blade reaches it. Treat the upper end as the planning assumption on south and west faces in summer and the lower end as a reasonable expectation on shaded northern glass.
| Hardness | 91 mg/L as CaCO₃ Moderately hard in the utility's own words; its customer guide gives a 60 to 120 range, as published by Knoxville Utilities Board. |
|---|---|
| pH | 7.3 |
| Alkalinity | 74 mg/L as CaCO₃ |
| Iron | 0.005 mg/L |
| Sodium | 11 mg/L |
| Chloride | 18 mg/L |
| Total dissolved solids | 150 mg/L |
| Disinfectant | free chlorine |
| Source and treatment | Tennessee River, drawn just downstream of the French Broad and Holston confluence, single source · Chlorine dioxide pre-disinfection, screening, coagulation and clarification, dual-media filtration, then final chlorine disinfection with fluoride and a zinc compound for corrosion control, at the Mark B. Whitaker plant · No softening step. |
Not in the report: corrosion index and manganese.
SOURCE · Knoxville Utilities Board 2024 Water Quality Report, additional monitoring table (average levels detected); the most recent edition reachable at kub.org · How we source these numbers
East Tennessee humidity and heavy tree cover set the interval far more than minerals do. Kudzu and ivy on older masonry reach the glazing line and hold moisture against it, which turns an ordinary north elevation into a biological problem rather than a dirt one. The university calendar overlays a second rhythm entirely, compressing commercial demand into the weeks before term and around home game weekends.
TENNESSEE SEASON BY SEASON →KUB treats Tennessee River water and calls it moderately hard, 60 to 120 mg/L in its own water quality guide, while figures quoted online range from roughly 79 to over 300 mg/L. Practically, the East Tennessee problems are biological: river-bottom humidity, kudzu and ivy at the glazing line, and shaded elevations that hold mildew. The university calendar compresses commercial demand into predictable, defensibly premium windows, with heritage sash in Old North Knoxville and Fourth and Gill as the technical speciality.
Knoxville Utilities Board draws a single source, the Tennessee River, at an intake just below the point where the French Broad and Holston join, and treats about 34 million gallons a day at the Mark B. Whitaker plant. The utility publishes its hardness as a 60 to 120 mg/L band and applies the moderately-hard label itself, so both ends of the working range come from the operator rather than from inference.
That spread is worth naming to customers directly. A Knoxville homeowner who has searched for their water hardness has almost certainly found a confident number with a confident band label attached, and there is roughly a fourfold chance the next site would have told them something different.
Kudzu and English ivy on older masonry are a glazing problem, not just a garden one. Growth reaches the frame line and holds moisture against the bead, which keeps the glass damp, accelerates mildew and rots putty. Pulling it off to reach the glass frequently takes the glazing bead with it.
The Tennessee Valley holds humidity in the river bottom and the shaded north sides of buildings stay damp much of the year. Biological film rather than mineral spotting is the recurring complaint here, and it needs a different chemistry and a shorter interval on exactly the elevations customers notice least.
The University of Tennessee compresses the commercial calendar into a few predictable spikes — move-in, graduation and home game weekends. Demand in those windows exceeds capacity every year, which makes them the most reliably profitable weeks on the books and worth protecting in a schedule.
Old North Knoxville, Fourth and Gill and Sequoyah Hills carry a concentration of Victorian and early-twentieth-century sash with original glass. Small panes, soft putty and uneven glass mean the per-opening time is several times a modern window and a blade is usually the wrong tool.
The university is the market's metronome. Football weekends and the start and end of term compress demand into predictable spikes, and premium pricing in those windows is both expected and sustainable. Student-adjacent rental property is the volume underneath that — high turnover, short intervals, and glass that is cleaned to a letting standard rather than a heritage one.
The routine work is genuinely approachable. The heritage stock is not, and Knoxville has an unusual amount of it — Old North Knoxville and Fourth and Gill carry Victorian sash with original glass where the panes are small, the putty is old and the glass is not flat. The other real hazard is vegetation: pulling ivy off a frame to reach the glass takes the glazing bead with it more often than people expect.
OPEN COST ESTIMATOR →2025 annual mean at the AIR LAB monitor, 939 Stewart St. Knoxville, TN 37917, 2.4 km north-east of the city (EPA site 47-093-1013).
2025 annual mean at the Rule High School (relo) monitor, 1613 Vermont Avenue, 0.8 km north of the city (EPA site 47-093-1017).
Largest air release: Explore Industries USA Inc, 2601 SEA RAY Blvd (plastics and rubber), inside the city limits, 345,305 lb in 2024.
KUB, which supplies Knoxville's water, can fix how much water customers may use, or restrict when and for what they use it, whenever an emergency or other condition leaves it short of water to meet demand. Customers who ignore such a restriction can be disconnected or charged extra for the excess.
KUB Rules and Regulations for the Water Division (Resolution 1347), Section VII: restricted use of water · checked September 2026
Knoxville bans causing or allowing an illicit discharge to the stormwater system or onto driveways, sidewalks, parking lots, sinkholes, creek banks or other areas that drain to it. Rinsing soapy water off a storefront onto the sidewalk falls under that ban.
Knoxville Code §22.5-52: prohibitions · checked September 2026
Every permit application for construction, alteration, repair, rehabilitation, relocation or demolition in a Knoxville H Historic Overlay District must be referred to the Historic Zoning Commission, which can ask for detailed plans before it issues a certificate of appropriateness.
Knoxville Zoning Code §16.8: overlay districts, certificates of appropriateness · checked September 2026
Peak yellow-pine-pollen pulse in late March. Wet-only handling. Do not scrape or run aggressive wash; pollen lifts cleanly with water plus light alkaline soap.
Memphis Midtown and shaded inner-city stock through Nashville and Chattanooga show heavy mold-and-mildew bloom on window frames and silicone bead. Hypochlorite or quaternary-ammonium pre-treatment.
Suction-cup tendril residue, chlorophyll staining, occasional plant-acid etching on tempered glass in extreme cases. Percarbonate handling on sash perimeter biological residue.
Knoxville runs on Knoxville Utilities Board lake or reservoir surface water at a published 91 mg/L (CaCO₃) — moderately hard in the utility's own words; its customer guide gives a 60 to 120 range. Knoxville Utilities Board publishes a band rather than a point, 60 to 120 mg/L, and calls its own water moderately hard.
Residential window cleaning in Knoxville typically runs $8–13 per pane or $240–430 for a standard single-story exterior. The university is the market's metronome. Football weekends and the start and end of term compress demand into predictable spikes, and premium pricing in those windows is both expected and sustainable.
Knoxville's drier, frost-free months are June and August to October, by NOAA's 1991–2020 normals for the Knoxville Experiment Station station, where March brings the most rain. The calendar on this page marks June (after the April 2 bloom) and October (after smoke season and before frost). Frost nights usually run from October 28 to April 11.
Yes, if the rinse is squeegeed off before it dries: Knoxville Utilities Board publishes dissolved solids of 150 mg/L, between this site's two dissolved-solids flags. Iron, manganese, sodium and chloride all sit under this site's flags (highest: sodium up to 11 mg/L). It draws on Tennessee River, drawn just downstream of the French Broad and Holston confluence, single source.
In Knoxville the dominant residue patterns include mildew and biological film on shaded, humid river-bottom elevations and kudzu and ivy growth reaching the glazing line on older masonry. East Tennessee humidity and heavy tree cover set the interval far more than minerals do.
The routine work is genuinely approachable. The heritage stock is not, and Knoxville has an unusual amount of it — Old North Knoxville and Fourth and Gill carry Victorian sash with original glass where the panes are small, the putty is old and the glass is not flat.
Restored commercial frontage with tall original openings and upper-floor residential conversion. Pedestrian-zone access limits vehicle placement, so equipment gets carried further than the job size suggests. Old North Knoxville and Fourth and Gill have their own housing stock and glazing as well.
Just over the Tennessee line