Evansville's Ohio River supply was 130 mg/L hard in the latest published figure, and heavy summer humidity stretches dry-down times across the city.
Evansville's Ohio River water sits right around the line where hard water begins, crossing it in some years, so expect light spotting when glass dries slowly. Heavy summer humidity stretches drying times across the city, and July to October is the best stretch. Humid days slow crews down, which belongs in the price; a single-story exterior runs $220 to $380.
Evansville's utility publishes one average a year, and the two most recent land either side of the line where hard water begins — 130 mg/L in the later year against 119 in the earlier. That is a real swing on a working river rather than a measurement error, and it is the reason to treat this number as this year's average rather than as the city's permanent chemistry. At either end it is enough to spot a pane left to dry in summer sun, which in a city with this long an exterior season is most of the year.
| Hardness | 130 mg/L as CaCO₃ No band label published; 130 mg/L is HARD on the USGS ladder, 119 the prior year was moderately hard. |
|---|---|
| Sodium | 32.2 mg/L |
| Disinfectant | chloramine |
| Source and treatment | Surface water, per the EPA SDWIS federal record · Powdered and granular activated carbon, pre-chlorination for taste and odour, coagulation, flocculation, rapid mix, sedimentation and rapid sand filtration, chlorination with chloramines as the residual, and fluoridation · No softening step. |
Not in the report: pH, alkalinity, corrosion index, iron, manganese, chloride and total dissolved solids.
SOURCE · Evansville Water and Sewer Utility 2025 Annual Drinking Water Quality Report, with the EPA SDWIS federal treatment record, PWS IN5282002 · How we source these numbers
Humidity is the controlling variable rather than season, because it lengthens dry-down across most of the year and makes marginal work on damp glass a real risk. River-facing elevations hold fog into the morning. Organic load runs long here — pollen through spring and a ragweed season that overlaps more working weeks than it does further north — and the salt season is comparatively short.
INDIANA SEASON BY SEASON →Evansville trades winter for humidity and a crew has to plan around the swap. The Ohio valley position in the far south-west of the state gives the longest exterior season in this cohort, so residential work stays viable across more of the year and the business is less dependent on commercial contracts to survive the cold months. What it costs is drying time: heavy summer air lengthens dry-down enough that the productive part of a midsummer day is shorter than the daylight, and early starts beat long afternoons. The sensible route order is downward — start on the higher east side and work toward the river as morning fog clears, which is the reverse of what suits a hillside city. Water is Ohio River supply, seasonally variable, and the utility's 2021 report puts hardness at 130 mg/L, up from 119 the year before. The riverfront historic stock is the local specialism: old and decorative glazing in the slowest-drying part of the city.
Evansville has the longest exterior working season of any city in this cohort, and that is the dominant commercial fact about the place. Sitting in the Ohio valley in the far south-west of the state, it sees a genuinely milder winter than the lake cities several hours north, which means residential exterior work stays viable across more of the calendar and a crew here is less dependent on a commercial book to survive the cold months.
The trade-off is humidity rather than cold. Ohio valley summers are heavy and the air holds moisture in a way that lengthens dry-down substantially, so the productive part of a midsummer day is shorter than the daylight suggests. Early starts are worth more here than long afternoons, which is the reverse of the advice that works in a dry climate.
The supply is Ohio River water treated by the municipal utility. A major navigable river is a different raw-water proposition from a lake — it varies with flow, it carries an upstream industrial spill risk, and its chemistry moves seasonally in a way open-lake water does not.
The utility publishes an average total hardness each year in its own annual report, and the recent pair sit either side of the hard threshold: 130 ppm, about 7.6 grains per gallon, in the most recent edition located, against 119 ppm or 7.0 grains the year before. A ten-unit year-to-year move on a big river is ordinary rather than alarming, but it does mean the figure is a yearly average of a moving supply rather than a fixed property.
River valley position gives the lowest elevations a persistent damp profile. Morning fog along the riverfront is common enough to be a scheduling input, and the sensible pattern is to start on the higher east side and work down toward the water as the day dries — the opposite of the order that suits a hillside city.
The historic riverfront stock combines two difficulties that usually arrive separately. The glazing is old and in places decorative, and the elevations facing the water are the slowest-drying in the city. Careful work in a short drying window is the local specialism and it should be priced as one.
The regional manufacturing base is current rather than historical, and the northern industrial frontage carries the deposit that goes with it. Glass there picks up a film that bonds when damp — and in this climate it is damp often — so detergent and contact time are not optional on that frontage.
Drying conditions are a genuine labour input here in a way they are not in drier climates, and a quote built on dry-climate productivity assumptions will lose money on humid days. Glazing age drives the riverfront historic stock. The long season is what keeps residential rates competitive, because crews are not recovering a closed winter in their summer pricing.
East Side post-war stock is reasonable homeowner work if it is done early in the day rather than in humid afternoon air. The riverfront historic district is not, because old and decorative glazing in a short drying window is the combination most likely to produce both a poor result and permanent damage. The northern manufacturing frontage is a contract job with lifts and a schedule attached.
OPEN COST ESTIMATOR →2025 annual mean at the Evansville- Buena Vista monitor, Evansville-Buena Vista-1110 W. Buena Vista Rd., 4.7 km north-west of the city (EPA site 18-163-0021).
Largest air release: RED Spot Paint & Varnish Co Inc, 1016 E Columbia ST (chemicals), inside the city limits, 34,656 lb in 2024.
Evansville Water and Sewer Utility's IURC-approved rate schedule treats hydrant water as a metered service: a contractor first takes out a temporary hydrant meter against a deposit, pays for the water used and brings the meter in each month for a reading, and anyone caught using a hydrant without authorization owes a $500 fee plus the cost of any hydrant repairs.
Evansville Water and Sewer Utility, 2021 Industrial Water Rates and Charges (IURC Order No. 45073): temporary fire hydrant meter fee · checked September 2026
Evansville's illicit discharge chapter forbids anyone to discharge any substance other than storm water or an exempted flow, directly or indirectly, into a city storm conveyance, watercourse or waterbody, and it reaches contaminated runoff as well as dumping; the Board of Public Works can order dischargers to adopt best management practices to keep pollutants out.
Evansville Municipal Code 13.25.020: prohibited discharges and connections · checked September 2026
In Evansville's historic districts, the Historic Preservation Commission must issue a certificate of appropriateness before a permit is issued or work begins on any conspicuous change to the exterior of a historic building, and its visual compatibility test specifically weighs the proportion of window openings and the pattern of solids and voids on front facades.
Evansville Municipal Code 2.106.030 and 2.106.080: commission powers; visual compatibility · checked September 2026
Wet-only handling. Peak mid-April. Pollen lifts cleanly with water plus light alkaline soap; do not scrape.
Crop dust and residual spray deposit on east-facing residential glass. Wet-rinse-first then standard wash. Lifts cleanly with water.
Sub-micron calcium-carbonate fraction resists standard acidic lift. Extended citric dwell (3-4 minutes) required. Same chemistry Cal Hatcher documents for Williamson County, Tennessee.
Road-treatment salt-aerosol load on east-facing exposures along the south shore. Wet-rinse pass before standard wash on late-winter visits.
Dune-and-marsh ecosystem along south shore supports heavy insect population. Chitin-protein residue needs higher soap concentration.
Late-summer algal bloom in the reservoir affects glass on lakefront residential. Slightly extended citric dwell handles the composite.
Evansville's utility publishes one average a year, and the two most recent land either side of the line where hard water begins — 130 mg/L in the later year against 119 in the earlier. That is a real swing on a working river rather than a measurement error, and it is the reason to treat this number as this year's average rather than as the city's permanent chemistry.
Residential window cleaning in Evansville typically runs $7–12 per pane or $220–380 for a standard single-story exterior. Drying conditions are a genuine labour input here in a way they are not in drier climates, and a quote built on dry-climate productivity assumptions will lose money on humid days.
Evansville's drier, frost-free months are July to October, by NOAA's 1991–2020 normals for the Evansville Regional Airport station, where May brings the most rain. The calendar on this page marks July (after the April 11 bloom) and October (after smoke season and before frost). Frost nights usually run from October 29 to April 4.
Not as the final rinse: Evansville Water and Sewer Utility publishes hardness of 130 mg/L, enough to spot as it dries, so finish with pure water. Water left to dry leaves mineral scale; fresh spots lift with a mild acid. Treatment starts with powdered, granular activated carbon, pre-chlorination for taste and odour.
In Evansville the dominant residue patterns include ohio river surface supply with seasonal variability — 130 mg/l in the utility's latest published figure and high summer humidity substantially lengthening dry-down across the whole city.
East Side post-war stock is reasonable homeowner work if it is done early in the day rather than in humid afternoon air. The riverfront historic district is not, because old and decorative glazing in a short drying window is the combination most likely to produce both a poor result and permanent damage.
Nineteenth and early twentieth-century housing facing the Ohio, with substantial glazing and decorative panels common. River-facing elevations hold damp longer than the street side of the same house. Haynie's Corner Arts District and Downtown and the riverfront have their own housing stock and glazing as well.
Just over the Indiana line