Charlotte Water is soft at 32 mg/L with just 59 mg/L dissolved solids, so the stains here are iron-rich Piedmont red clay and March to April pine pollen.
Charlotte's water is soft, so it leaves almost nothing behind on glass; what stains windows here is iron-rich red clay and the yellow pine pollen of early spring. Wash in April or May once the pollen settles, or in July, September or October. Access sets the price more than pane count, and a single-story exterior runs $320 to $540.
At 32 ppm, with magnesium at 1.7, Charlotte's supply deposits almost nothing and what it does leave is calcium that lifts with a mild acid. The variable worth attention is not the mineral content but the pH — this water runs alkaline enough that the state widened the allowed range for it, and that changes how a cleaner behaves far more than 32 ppm of hardness does.
| Hardness | 32 mg/L as CaCO₃ Soft — 32 ppm sits well inside the 0 to 60 soft band, with a published range of 27 to 35. |
|---|---|
| pH | 8.5 (range 7.4–9.5) |
| Alkalinity | 21 mg/L as CaCO₃ |
| Iron | 0.0057 mg/L |
| Manganese | 0.0045 mg/L |
| Sodium | 3.6 mg/L |
| Chloride | 6.4 mg/L |
| Total dissolved solids | 59 mg/L |
| Disinfectant | free chlorine |
| Source and treatment | Mountain Island Lake and Lake Norman, Catawba River basin · Powdered activated carbon, alum coagulation, settling, filtration, chlorine, fluoride, and lime for pH control, at three plants · No softening step. |
Not in the report: corrosion index.
SOURCE · Charlotte Water, 2025 Annual Drinking Water Quality Report, water system 01-60-010 — 'Other Miscellaneous Water Characteristics Contaminants – At Entry Point to Distribution System', Disinfectant Residuals Summary, Our Treatment Process, and the additional unregulated-contaminant table (read as republished in full by York County, SC, which buys Charlotte water) · How we source these numbers
Pollen sets the residential interval here, not minerals. The March-to-April pine wave is an event rather than a season and there is no point servicing a house in the middle of it; the sensible pattern is a hard reset once it clears, then a lighter cycle driven by canopy and red-clay splatter. Uptown runs on its own contract calendar entirely, independent of any of this.
NORTH CAROLINA SEASON BY SEASON →Charlotte Water publishes total hardness at 32 ppm — soft, and almost entirely calcium, with magnesium at just 1.7. What the same table shows that matters more is pH: an average of 8.5 ranging to 9.5, under a state-granted corrosion-control window of 7.0 to 9.2 rather than the usual 6.5 to 8.5 ceiling. Alkaline water works with an alkaline cleaner instead of against it. Beyond the tap it is pine pollen, Piedmont red clay, and the only real high-rise book in the Carolinas.
Charlotte Water publishes total hardness at 32 ppm, ranging 27 to 35, with calcium hardness at 25 and magnesium at only 1.7. That is soft by any scale and it is unusually calcium-dominated — there is very little magnesium in this water at all, which is why what little residue forms lifts with an ordinary acidic cleaner rather than needing anything stronger.
The more consequential number in the same table is pH: average 8.5, ranging 7.4 to 9.5. The state's Public Water Supply Section has given Charlotte Water a widened operating window of 7.0 to 9.2 specifically for corrosion control, against the ordinary secondary standard of 6.5 to 8.5. Lime is dosed to hold it there. For glass that means the supply is reliably alkaline, so a strong alkaline cleaner has nothing tempering it — dilute below the label rate.
Three plants — Franklin, Dukes and Vest — treat about 125 million gallons a day from Mountain Island Lake and Lake Norman, and the utility publishes one set of figures across all three rather than per-plant values. Total dissolved solids sit at 59 ppm against 32 of hardness, so there is not much of anything dissolved in this water.
The state's source water assessment rates Lake Norman at higher susceptibility to contamination and Mountain Island Lake at moderate, which is worth knowing because it drives the taste-and-odour treatment: powdered activated carbon is dosed routinely, and PFAS from legacy upstream industry on the Catawba is a live regional issue rather than a settled one.
Pine pollen through March and April coats every surface in the city, and it is the single event that resets the residential calendar. It is coarse, it is yellow, and it comes back within days of a wash during the peak — booking work inside the window is how a crew gets a complaint for something it did nothing wrong on.
Piedmont red clay is iron-rich and splatters onto lower panes and sills from beds, verges and the city's continuous construction. Left through repeated wet-dry cycles it stains rather than washes, and lifting it needs an oxalic or acid step that the soft water gives no other reason to carry.
Uptown is the only genuine high-rise glazing concentration in the Carolinas, and it is a different business from the rest of the market — rope access or powered platform, specific insurance, night and weekend scheduling around building operations. It is where the revenue ceiling in this market sits, and it is not reachable by scaling up residential work.
The city's growth is the quiet operational fact. Charlotte Water runs over 4,600 miles of main and the metro adds population continuously, so route density in the newer southern and northern suburbs changes year to year in a way established markets do not.
Access is the whole price structure in Charlotte. Uptown high-rise elevations price on rigging, insurance and out-of-hours scheduling rather than on pane count; Myers Park and Dilworth price on heritage sash and canopy loading; and the southern growth corridor prices on route density, which is the one thing that has been improving as the metro fills in. Water treatment is not a cost driver here at all.
Soft water and accessible suburban glazing make a homeowner result realistic across SouthPark and the southern corridor, and the one genuine caution is chemical rather than physical: this water is alkaline, so mixing a cleaner strong makes streaking worse rather than better. Two things do not transfer — red-clay staining, which needs an acid step and gets scrubbed instead, and Uptown, which is rope-access work under building coordination and a different trade entirely.
OPEN COST ESTIMATOR →2025 annual mean at the Garinger High School monitor, 1130 Eastway Drive, 5.4 km north-east of the city (EPA site 37-119-0041).
2025 annual mean at the Remount monitor, 1030 Remount Road, 3.9 km west of the city (EPA site 37-119-0045).
Largest air release: SNYDER'S-Lance Inc., Crump RD (food), inside the city limits, 130,347 lb in 2024.
Charlotte's water-use controls apply only under a water shortage declaration: Phase I can restrict or ban discretionary uses such as noncommercial pressure washing and residential car washing, and Phase II can ban them outright. Commercial pressure washing is classed separately, as a community and business use, so Phase I controls on discretionary uses do not reach it.
Charlotte Code §23-252: water conservation definitions · Charlotte Code §23-256: Phase I, restricted · checked September 2026
Charlotte's stormwater ordinance bars anyone from letting non-stormwater or any pollutant reach the storm system or state waters, directly or by leaving it on land where it is likely to get there, unless the code's allowed list covers it. Whoever causes such a discharge must collect it at once and restore the area, so plan to capture soapy wash water before it runs to a drain.
Charlotte Code §18-80: stormwater prohibitions · checked September 2026
In Charlotte's local historic districts, such as Dilworth, Wilmore and Fourth Ward, replacing windows or doors needs a Certificate of Appropriateness from the Historic District Commission, and staff can approve replacements that meet the commission's design guidelines. The certificate's placard has to be displayed along with any required permits while the work goes on.
Charlotte Historic District Commission, COA HDCADMRM-2019-00679 (replacement windows and doors, staff approval) · Charlotte Historic District Commission, COA HDCADMRM-2018-00110 (window replacement, Fourth Ward) · checked September 2026
The Triangle and eastern Piedmont parent rock weathers to a more iron-bearing clay than the Atlanta Piedmont. Lower-sash splatter on intown stock needs oxalic rather than citric to lift cleanly. A citric-only protocol leaves a faint orange ghost stain.
Loblolly and shortleaf pine pollen blankets south-facing exposures for two to three weeks each spring. Same handling as Atlanta: wet only, never scrape, light alkaline wash to lift the film.
At 32 ppm, with magnesium at 1.7, Charlotte's supply deposits almost nothing and what it does leave is calcium that lifts with a mild acid. The variable worth attention is not the mineral content but the pH — this water runs alkaline enough that the state widened the allowed range for it, and that changes how a cleaner behaves far more than 32 ppm of hardness does.
Residential window cleaning in Charlotte typically runs $11–16 per pane or $320–540 for a standard single-story exterior. Access is the whole price structure in Charlotte.
Charlotte's drier, frost-free months are April and May, July and September and October, by NOAA's 1991–2020 normals for the Charlotte Douglas Airport station, where March brings the most rain. The calendar on this page marks April (after the March 23 bloom), September (after smoke season) and October (before frost). Frost nights usually run from November 3 to March 30.
Usually yes: Charlotte Water publishes dissolved solids of 59 mg/L, low enough that tap-rinsed glass tends to dry clean. Iron, manganese, sodium and chloride all sit under this site's flags (highest: manganese up to 0.0045 mg/L). It draws on Mountain Island Lake and Lake Norman, Catawba River basin.
In Charlotte the dominant residue patterns include pine pollen wave (march–april) and iron-rich piedmont red-clay splatter. Pollen sets the residential interval here, not minerals.
Soft water and accessible suburban glazing make a homeowner result realistic across SouthPark and the southern corridor, and the one genuine caution is chemical rather than physical: this water is alkaline, so mixing a cleaner strong makes streaking worse rather than better.
The banking core and the only real high-rise glazing concentration in the state. Rope access and powered platform work, formal building coordination, and quarterly institutional contracts rather than one-off jobs. Dilworth and Myers Park have their own housing stock and glazing as well.
Just over the North Carolina line