Greensboro water is soft at 34 to 51 mg/L, pine pollen coats glass in March and April, and iron-rich Piedmont red clay splatters the lower panes.
Greensboro's water is soft and a tap rinse finishes clean on most homes, so any spot on the glass is almost always organic: pollen, sap or red clay. Pine pollen coats glass in early spring, so wash once it clears in April, or from August to October. Heritage homes in Irving Park and Fisher Park take slow, careful work at a different rate from post-war houses nearby, and a single-story exterior runs $260 to $440.
At 2 to 3 grains the supply contributes very little to what ends up on the glass, and tap rinsing finishes clean on most residential work. The practical consequence is that a spot in Greensboro is almost always organic — pollen, sap, clay — rather than mineral, and reaching for an acid when a surfactant is wanted is the common local mistake.
Figures by plant, as reported.
| Hardness | 34–51 mg/L as CaCO₃ 2 to 3 grains per gallon in the department's own words; soft on the USGS scale, which the city's page labels 'moderately soft' on its own ladder, as published by Greensboro Water Resources. |
|---|---|
| pH | 8.1–8.2 |
| Alkalinity | 36–38 mg/L as CaCO₃ |
| Iron | 0.02–0.03 mg/L |
| Manganese | < 0.01 mg/L |
| Sodium | 15.1–16.8 mg/L |
| Chloride | 12 mg/L |
| Total dissolved solids | 112–113 mg/L |
| Disinfectant | chloramine |
| Source and treatment | Lake Brandt, Lake Higgins and Lake Townsend, treated at the Mitchell and Townsend plants · Algae control, permanganate and pre-chlorination, pre pH adjustment, coagulation, flocculation, rapid mix, lime and soda ash softening with sedimentation and rapid sand filtration, granular activated carbon, sludge treatment, chlorination with chloramines as the residual, fluoridation, with a polyphosphate inhibitor and post pH adjustment · The plant softens. |
Not in the report: corrosion index.
SOURCE · City of Greensboro Water Quality Report, Monthly Inorganic Averages for November 2025 (Townsend and Mitchell finished water), with the EPA SDWIS federal treatment record, PWS NC0241010 · How we source these numbers
The pollen wave is the fixed point of the calendar and everything arranges around it: there is no value in servicing a house in late March, the reset comes once it clears, and after that the interval is set by canopy and by how much bare clay sits next to the building. Nothing in the supply pushes the frequency either way.
NORTH CAROLINA SEASON BY SEASON →Greensboro Water Resources states on its own site that the city's water runs 2 to 3 grains per gallon — roughly 34 to 51 mg/L, soft on the USGS scale. That changes the commercial conversation: tap rinsing gets spot-free results on most residential work, so the deionised upsell that carries other markets is weak here. The seasonal problem is organic rather than mineral — the pine pollen wave in March and April, and iron-rich red-clay splatter that stains if it is left to cycle wet and dry.
Greensboro blends surface water from its own reservoirs — Lake Brandt, Lake Higgins and Lake Townsend on the Reedy Fork system — through two plants, Mitchell on Battleground Avenue taking the Brandt and Higgins water and Townsend taking Lake Townsend's. Piedmont surface water over granite and gneiss comes out soft, and the department puts it at 2 to 3 grains per gallon.
That softness is a commercial argument rather than a technical footnote. Spot-free results are achievable with tap rinsing on most residential work, which means the deionised-rinse premium that sells easily in Texas or Utah is a harder sell in Greensboro — and pricing should reflect what the water actually requires.
The city's own hardness page is worth reading for a reason beyond the number. It notes that the Water Quality Association — which the page describes as a self-monitoring trade association of the home and commercial water treatment industry — revised the classifications so that only water below 1.0 grain counts as soft and 1.0 to 3.5 becomes slightly hard. The same water is soft by the federal scale and slightly hard by the softener industry's. Anyone quoting a hardness band should know which ladder they are standing on.
The March-to-April pine pollen wave is the defining seasonal event. It arrives as a visible yellow film that coats every horizontal and vertical surface in the city within days, and it is coarse enough to smear badly if worked dry. Presoak and flood; never start with a dry pass during the wave.
Piedmont red clay is iron-rich, and rain splatter off unpaved edges and flower beds leaves ferrous staining on lower panes and sills. Left through repeated wet-dry cycles it bonds, and clearing it needs an acid or oxalic step rather than detergent.
The two universities sit close enough together to be planned as one institutional book. Their calendars broadly align, which concentrates campus contract work and student-rental turnover into the same narrow windows rather than spreading it across two schedules.
Greensboro's textile and furniture money built an unusually deep stock of pre-1930 architect-designed housing for a city of its size, concentrated in Irving Park and Fisher Park. Art glass, leaded panels and original wavy single-pane are common enough here that conservation skills are a routine requirement, not a specialism.
Greensboro sells water on into Jamestown, which routes part of its supply through Greensboro's distribution lines alongside water from High Point and the Piedmont Triad Regional Water Authority. Work taken just outside the city limits is not necessarily on Greensboro water, and on the Jamestown side it may be a blend of three systems.
Two things move the number in Greensboro. Heritage handling in Irving Park and Fisher Park is slow, careful work at a genuinely different rate from the post-war stock a mile away. The university book is the other half — campus contracts and student-rental turnover compress into aligned calendars at both institutions, so capacity in those windows is worth more than it is the rest of the year. The water itself is not a cost driver.
Soft water and ordinary suburban glazing put a good result within a careful homeowner's reach across Sunset Hills and Lake Daniel. The genuine exclusions are the pre-1930 architect-designed stock in Irving Park and Fisher Park, where art glass and leaded panels do not tolerate a scraper or a strong alkaline cleaner, and bonded red-clay staining, which needs an oxalic step that most households will not attempt and should not improvise.
OPEN COST ESTIMATOR →2025 annual mean at the Mendenhall School monitor, 205 Wiloughby Blvd, 2.5 km north-east of the city (EPA site 37-081-0013).
Largest air release: Sherwin-Williams Co, 113 Stage Coach Trail (chemicals), inside the city limits, 33,220 lb in 2024.
Greensboro's Water Shortage Response Plan (June 2023) bars sprinklers from throwing water onto pavement at any time. In Stage III it becomes unlawful to wash down office buildings, home exteriors, sidewalks or patios, but licensed commercial pressure washers may keep working and hand washing to prep a surface for paint is allowed; non-residential fines run $200, $500, then $1,000.
City of Greensboro, Water Shortage Response Plan (June 2023) · checked September 2026
Greensboro makes it unlawful to run, or let run, water or liquid of any kind onto a street or sidewalk, by pipe or otherwise, and to let drainage from a lot pour across the sidewalk; only rainwater properly carried across to the gutter is exempt, so a wash crew needs to catch its runoff.
Greensboro Code Sec. 26-16: drainage across sidewalks prohibited · checked September 2026
In Greensboro's local historic districts (Fisher Park, College Hill and others) a certificate of appropriateness is required for exterior work; staff issue minor works and the Historic Preservation Commission hears major ones. Windows get real scrutiny: in 2016 the commission denied swapping original windows at 622 South Mendenhall Street for vinyl units with the same muntin pattern.
City of Greensboro, steps for obtaining a certificate of appropriateness (2025) · Greensboro Historic Preservation Commission minutes: vinyl replacement windows denied · 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.
Greensboro runs on Greensboro Water Resources lake or reservoir surface water at a published 34–51 mg/L (CaCO₃) — 2 to 3 grains per gallon in the department's own words; soft on the USGS scale, which the city's page labels 'moderately soft' on its own ladder.
Residential window cleaning in Greensboro typically runs $8–13 per pane or $260–440 for a standard single-story exterior. Two things move the number in Greensboro. Heritage handling in Irving Park and Fisher Park is slow, careful work at a genuinely different rate from the post-war stock a mile away.
Greensboro's drier, frost-free months are April and August to October, by NOAA's 1991–2020 normals for the Piedmont Triad International Airport station, where July brings the most rain. The calendar on this page marks August (after the April 1 bloom), September (after smoke season) and October (before frost). Frost nights usually run from November 5 to March 30.
Yes, if the rinse is squeegeed off before it dries: Greensboro Water Resources publishes dissolved solids of 112–113 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 16.8 mg/L). It draws on Lake Brandt, Lake Higgins and Lake Townsend, treated at the Mitchell and Townsend plants.
In Greensboro the dominant residue patterns include pine pollen wave (march–april) and iron-rich piedmont red-clay splatter.
Soft water and ordinary suburban glazing put a good result within a careful homeowner's reach across Sunset Hills and Lake Daniel.
The city's pre-1930 mansion district. Original wood sash, leaded and art glass in several houses, and owners who expect conservation handling as a baseline. Fisher Park and Downtown Greensboro have their own housing stock and glazing as well.
Just over the North Carolina line