Chattanooga's shaded, humid river bowl grows mildew and biological film, and kudzu and ivy climb to the glazing line on older masonry buildings.
Chattanooga's Tennessee River water is soft to moderately hard, so scale is not the issue; the humid river bowl is, growing mildew and biological film on shaded walls while kudzu and ivy climb older masonry. Humidity eases enough for washes to hold in May and from August to October. Lookout Mountain and the ridge homes combine difficult access with big glass, so quotes there need a site visit; a single-story exterior runs $240 to $430.
The operator gives this water as 54 to 90 mg/L and, unusually, prints the grains-per-gallon conversion beside it rather than leaving the customer to do the arithmetic. Neither end of that span is a scale problem. What shapes the work here instead is the pH, which the same sheet puts at 6.9 to 7.4 — essentially neutral, and low enough that an alkaline cleaner is not being fought by the water it is diluted in. That is a friendlier starting chemistry than most of the large systems on this site.
Figures by plant, as reported.
| Hardness | 54–90 mg/L as CaCO₃ No band label published; the span runs from slightly hard into moderately hard on the USGS ladder. |
|---|---|
| pH | 6.9–7.4 |
| Iron | not detected |
| Manganese | not detected |
| Sodium | 3.8–4.6 mg/L |
| Chloride | 11.7 mg/L (range 11.3–12) |
| Total dissolved solids | 85 mg/L (range 76–94) |
| Disinfectant | free chlorine |
| Source and treatment | The Tennessee River, drawn at the Citico Water Treatment Plant in Chattanooga, which also supplies East Ridge, Elder Mountain, Lookout Mountain, Red Bank and Signal Mountain, and wholesale customers across the Georgia line. About 43 million gallons a day. · Conventional surface-water treatment with filtration held to a turbidity treatment technique, chlorine applied at the plant and carried as a continual residual through the distribution system, orthophosphate for corrosion control, and fluoride added as required by local law. · No softening step. |
Not in the report: alkalinity and corrosion index.
SOURCE · Tennessee American Water, 2025 Annual Water Quality Report for the Citico Water Treatment Plant, PWS ID TN0000107 — 'Additional Water Quality Parameters of Interest: Water Leaving the Treatment Facility' table plus the source, turbidity and disinfection sections (amwater.com/ccr/chattanooga.pdf) · How we source these numbers
Chattanooga sits in a river bend ringed by ridges, and that traps both moisture and air. Shaded elevations hold damp long enough for mildew to establish, and the valley's historic tendency to hold particulate against the ridges means industrial film settles rather than blowing through. Climbing vegetation on older masonry adds a third clock that runs independently of weather.
TENNESSEE SEASON BY SEASON →Tennessee American Water draws the Tennessee River and its Citico plant sheet puts hardness at 54 to 90 mg/L, soft to moderately hard; figures quoted online, 71 and 131 mg/L, disagree with each other. The city's bowl topography traps moisture and air, making mildew and industrial film the recurring problems rather than mineral spotting. Lookout Mountain access, not pane count, sets the price on the high-end residential book, and climbing vegetation at the glazing line is a repair risk on the older masonry stock.
Tennessee American Water treats Tennessee River water at the Citico plant, roughly 40 million gallons a day, and the same plant supplies parts of north Georgia as well as the Chattanooga area — so a crew working south across the state line may still be on identical water. The utility publishes total hardness at 54 to 90 mg/L with iron and manganese both undetected, which removes the two metals most likely to stain glass and frames from the list of things to plan around.
The city sits in a bend of the river ringed by Lookout Mountain, Signal Mountain and Missionary Ridge, and that bowl holds both moisture and air. It is the reason Chattanooga had one of the worst air-quality reputations in the country in the mid-twentieth century, and the reason shaded glass here stays damp longer than the regional average would suggest.
Kudzu and ivy cover a great deal of older masonry and reach the glazing line. Beyond the moisture it traps against the bead, the growth has to be cut back rather than pulled — pulling takes putty and sometimes the bead with it, converting a cleaning visit into a glazing repair.
The Volkswagen plant and the wider manufacturing corridor put an industrial film on nearby commercial glass that is oily rather than mineral. A detergent chosen for spotting smears it, so those accounts need a surfactant step written into the quote rather than discovered on site.
Lookout Mountain property is an access problem before it is a glass problem. Steep driveways, long drops below the working elevation and large view-facing panes mean the approach has to be surveyed before a price is given, and a per-pane rate carried up from the valley will not cover the day.
Civil War tourism at Chickamauga and the Lookout Mountain battlefields, plus the riverfront attractions, give the city an institutional and hospitality book that peaks sharply in the warm months and carries scheduling constraints around public opening hours.
Topography prices this market. Lookout Mountain and the ridge properties combine difficult vehicle access, steep ground and large glazed elevations, and a quote priced on pane count without seeing the approach will be wrong. Tourism around the Civil War sites and the riverfront gives a seasonal institutional and hospitality book with its own scheduling constraints.
Ordinary residential work is straightforward. Two things are not. Lookout Mountain property means steep access, long drops and frequently large view-facing glass in exposed positions, which is a rigging question before it is a cleaning one. And the manufacturing corridor puts a genuine industrial film on nearby glass that needs a surfactant step rather than more effort with a squeegee.
OPEN COST ESTIMATOR →2025 annual mean at the Siskin monitor, Riverside Substation 911 Siskin DR, 4.4 km west of the city (EPA site 47-065-4002).
Largest air release: Volkswagen Group of America Chattanooga Operations LLC., 8001 Volkswagen Drive (transportation equipment), inside the city limits, 117,626 lb in 2024.
Tennessee American Water, Chattanooga's supplier, restricts its fire hydrants to firefighting under fire-department control. Its TPUC tariff says no water may be drawn from a hydrant for construction, street sprinkling, flushing gutters or any other use without the company's written authorisation, and whoever operates one pays for any damage.
Tennessee American Water tariff TPUC No. 20, Rule 24: public fire hydrants · checked September 2026
Chattanooga lists direct and indirect discharges into community or state waters that are unlawful, among them sewage dumping, chlorinated pool water and polluted household wastewater.
Chattanooga Code §31-341: illicit discharge and illegal dumping · checked September 2026
In a Chattanooga local historic district, a certificate of appropriateness is required for any permit to build, alter, rehabilitate, relocate or demolish a building or other improvement.
Chattanooga Code §10-15: certificates of appropriateness · checked September 2026
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.
The operator gives this water as 54 to 90 mg/L and, unusually, prints the grains-per-gallon conversion beside it rather than leaving the customer to do the arithmetic. Neither end of that span is a scale problem.
Residential window cleaning in Chattanooga typically runs $8–13 per pane or $240–430 for a standard single-story exterior. Topography prices this market. Lookout Mountain and the ridge properties combine difficult vehicle access, steep ground and large glazed elevations, and a quote priced on pane count without seeing the approach will be wrong.
Chattanooga's drier, frost-free months are May and August to October, by NOAA's 1991–2020 normals for the Chattanooga Lovell Airport station. The calendar on this page marks May (after the March 24 bloom) and October (after smoke season and before frost). Frost nights usually run from November 9 to March 24. Normal highs reach 90°F in July and August.
Usually yes: Tennessee American Water publishes dissolved solids of 85 mg/L, low enough that tap-rinsed glass tends to dry clean.
In Chattanooga the dominant residue patterns include mildew and biological film in the shaded, humid river bowl and kudzu and ivy growth reaching the glazing line on older masonry. Chattanooga sits in a river bend ringed by ridges, and that traps both moisture and air.
Ordinary residential work is straightforward. Two things are not. Lookout Mountain property means steep access, long drops and frequently large view-facing glass in exposed positions, which is a rigging question before it is a cleaning one.
Riverfront commercial and converted industrial stock with tall original openings, plus post-2000 residential conversion. Public-realm access means most work is scheduled before opening hours. Fort Wood and St. Elmo have their own housing stock and glazing as well.
Just over the Tennessee line