Lexington water runs 149 to 161 mg/L hard and leaves a magnesium-bearing scale that resists a mild acid, while mature canopy drips honeydew and tannin.
Lexington's water is hard, so neglected glass becomes hard to bring back and a regular cleaning interval pays off. Mature canopy drips honeydew and tannin onto the glass, and July to October is the best stretch to wash. Canopy-heavy streets need more frequent visits, and a single-story exterior runs $240 to $430.
At about 150 milligrams per litre from every plant this is hard water, and the average hides a wide spread: 2025 samples ran from 60 to 340. The 2025 plant table puts magnesium at only 4 to 5 milligrams per litre against calcium of 19 to 40, so the deposit is mostly calcium and a mild acid lifts it; the work is in volume and timing rather than chemistry. Expect the near-neutral pH to mean cleaners behave at close to their stated strength.
Figures by plant, as reported.
| Hardness | 149–161 mg/L as CaCO₃ Hard — plant averages of 161 ppm as CaCO3 (Kentucky River Station), 149 (Richmond Road) and 153 (Kentucky River Station II), about 9 grains per gallon each; individual samples ran 60 to 340, as published by Kentucky American Water. |
|---|---|
| pH | 6.7–8.2 |
| Alkalinity | 17–220 mg/L as CaCO₃ |
| Iron | not detected |
| Manganese | not detected |
| Sodium | 6.4–34 mg/L |
| Chloride | 18–93 mg/L |
| Total dissolved solids | 168–304 mg/L |
| Disinfectant | chloramine |
| Source and treatment | Three surface-water plants serving Fayette, Clark, Scott, Jessamine, Harrison, Bourbon and Woodford counties: Kentucky River Station on pool 9 of the Kentucky River south of Lexington, Richmond Road Station on Jacobson Reservoir, and Kentucky River Station II on pool 3 of the river in Owen County. About 42 million gallons a day. · Chloramine disinfection, with a residual of 3.29 mg/L leaving the plant falling to 2.62 mg/L in the distribution system, plus fluoride at 0.77 mg/L. No softening step is named and finished hardness stays at 150 mg/L, 8.8 grains per gallon. · No softening step. |
Not in the report: corrosion index.
SOURCE · Kentucky American Water 2025 Annual Water Quality Report, Central & Northern Division (KY0340250), 'Additional Water Quality Parameters of Interest - Water Leaving the Treatment Facility', per plant · How we source these numbers
Mineral spotting is a year-round baseline in this city rather than a seasonal event, so intervals are shorter than in the soft-water markets and the case for a recurring schedule is easy to make. Overlaid on that: a heavy spring pollen period best waited out, honeydew through the growing season in the canopy neighbourhoods, and road salt on commercial frontages through winter. The farm corridors add paddock and harvest dust on their own schedule entirely.
KENTUCKY SEASON BY SEASON →Kentucky American's 2025 annual report gives what matters plant by plant: total hardness averaging 149 to 161 mg/L (about 9 gpg), calcium 19 to 40 and magnesium 4 to 5; its older typical-quality sheet gave 150 mg/L with calcium 39 and magnesium 13. The composition has shifted since that sheet: with magnesium now at 4 to 5, the deposit is mostly calcium, so a mild acid lifts it and the work is about volume and timing. Three surface plants on the Kentucky River and a county reservoir supply about 42 MGD, disinfected with chloramines at a near-neutral pH averaging 7.5 to 7.7.
Kentucky American Water's 2025 annual report prints the numbers this trade actually needs, plant by plant, for water leaving treatment: total hardness averaging 161 milligrams per litre at Kentucky River Station, 149 at Richmond Road and 153 at Kentucky River Station II, about 9 grains per gallon at each.
It also prints the components, which is rarer and more useful: calcium averaging 19, 40 and 34 milligrams per litre at the three plants, and magnesium 4 to 5.
The company's older typical-quality sheet gave a 150 total with calcium 39 and magnesium 13, so the total has held steady across the two documents.
The composition is the part that changes method. The older sheet's magnesium, at 13 milligrams per litre, made up a substantial share of the total, and magnesium-bearing deposits resist the mild acid that lifts pure calcium scale; the 2025 plant table puts magnesium at 4 to 5, so today's water is more calcium-dominated than that sheet suggested.
What has not changed is the total: at roughly 150 milligrams per litre from every plant this is hard water, and individual samples ran from 60 to 340 in 2025, so some weeks are far harder than the average.
Three treatment plants feed the service area — two drawing separate pools of the Kentucky River and one drawing a reservoir inside the county — and all three are surface sources, supplying roughly 42 million gallons a day.
The utility disinfects with chloramines rather than free chlorine, running 3.29 milligrams per litre leaving the plant and 2.62 in the distribution system.
pH leaves the plants at 7.5 to 7.7 on average, close to neutral. That is genuinely useful: cleaners behave near their label strength here rather than being amplified or blunted by an alkaline supply.
Iron and manganese both come back not detected, so coloured staining is not a local risk and any rust marking on glass here comes from the frame or the fixings rather than the water.
Bluegrass limestone is the reason for the mineral content and it also shapes the market above ground — the horse farm economy supports a category of high-value estate work that a city this size would not otherwise generate.
Mature canopy across Ashland Park and Chevy Chase brings honeydew and leaf tannin onto the glass beneath, and the older stock there carries divided lights where pane count rather than area sets the time.
Hardness is one of the few markets on this site where the water genuinely is a cost driver, because it shortens the interval and makes neglected glass materially harder to recover. Beyond that: canopy and pane count price the historic residential districts above their area; campus and rental work prices on the summer window; the eastern retail corridor prices on route density; and the horse farm corridors price on drive time and on a client base that does not shop on rate.
A homeowner can work here but should expect the water to fight back in a way it does not in a soft-water city. Let a pane dry with this supply on it and the magnesium fraction leaves something a general-purpose cleaner will not lift — the discipline is to keep the glass wet and finish it, not to escalate the product. Established etching from years of drying deposits is restoration rather than cleaning. The estate and farm work is a different business built on relationships and discretion.
OPEN COST ESTIMATOR →2025 annual mean at the Lexington Primary monitor, Fayette County Health Dept, 650 Newtown Pike, 4.4 km north-west of the city (EPA site 21-067-0012).
Largest air release: Central Kentucky Processing Inc, 2580 Palumbo DR (fabricated metals), inside the city limits, 3,467 lb in 2024.
Lexington's water is sold by Kentucky American Water under a PSC-approved tariff. Rule 8.2 lets the company restrict, limit or curtail any customer's water use when supplies can't meet demand and still keep fire reserves, and Rule 4.1 lets it disconnect service for wilful or careless waste that affects other customers.
Kentucky-American Water Company tariff (Kentucky PSC): Rules 4.1 and 8.2 · checked September 2026
Lexington's stormwater chapter forbids starting or continuing any illicit discharge to the storm drains. Its exempt list names lawn watering, potable line flushing and non-commercial car washing, but not commercial wash water, so a crew's runoff is covered; the Division of Water Quality can also require a business whose premises may be a source to install pollution controls at its own cost.
Lexington-Fayette Code §16-93: illicit discharges and exempt discharges · Lexington-Fayette Code §16-91: pollution-control requirements · checked September 2026
Inside an H-1 overlay, Lexington's zoning ordinance requires a certificate of appropriateness from the Board of Architectural Review (or its staff) before any exterior change. Ordinary maintenance is exempt when it repairs existing features or swaps in identical pieces and leaves the look unchanged, so reglazing a sash in kind is fine while a new window style is not; repainting a painted surface never needs one.
Lexington-Fayette Zoning Ordinance §13-7: certificates of appropriateness · checked September 2026
Karst sub-micron suspended-particulate variant that resists standard acidic lift. Extended citric dwell (3-4 minutes) required. Same protocol Cal Hatcher documents for Middle Tennessee.
Wet-only handling. Peak mid-April. Pollen lifts cleanly with water plus light alkaline soap; do not scrape.
Lexington runs on Kentucky American Water lake or reservoir surface water at a published 149–161 mg/L (CaCO₃) — hard — plant averages of 161 ppm as CaCO3 (Kentucky River Station), 149 (Richmond Road) and 153 (Kentucky River Station II), about 9 grains per gallon each; individual samples ran 60 to 340.
Residential window cleaning in Lexington typically runs $8–13 per pane or $240–430 for a standard single-story exterior. Hardness is one of the few markets on this site where the water genuinely is a cost driver, because it shortens the interval and makes neglected glass materially harder to recover.
Lexington's drier, frost-free months are July to October, by NOAA's 1991–2020 normals for the Lexington Bluegrass 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 28 to April 13.
Not as the final rinse: Kentucky American Water publishes dissolved solids of 168–304 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. The supply is treated with chloramine, which lasts in a bucket and wears deionising resin faster. It draws on three surface-water plants serving Fayette.
In Lexington the dominant residue patterns include magnesium-bearing scale that resists a mild acid and honeydew and tannin under mature canopy. Mineral spotting is a year-round baseline in this city rather than a seasonal event, so intervals are shorter than in the soft-water markets and the case for a recurring schedule is easy to make.
A homeowner can work here but should expect the water to fight back in a way it does not in a soft-water city. Let a pane dry with this supply on it and the magnesium fraction leaves something a general-purpose cleaner will not lift — the discipline is to keep the glass wet and finish it, not to escalate the product.
The oldest surviving fabric in the city, Federal and Greek Revival houses beside a civic core of later commercial stock. Original glass in quantity and conservation pacing throughout. Ashland Park and Chevy Chase have their own housing stock and glazing as well.
Just over the Kentucky line