Allentown water is very hard at 180 to 284 mg/L, limestone-groundwater irrigation overspray marks dark frames, and spring pollen fills the Lehigh Valley.
Allentown's water is hard to extremely hard, limestone groundwater averaging about 15 grains per gallon, so irrigation overspray marks dark frames and any rinse left to dry will spot. Spring pollen fills the Lehigh Valley, and June, August and September are the best months to wash. The valley's warehouse boom means a lot of modern low-rise commercial glass priced on volume, while a single-story home exterior runs $260 to $440.
LCA's 2025 report averages 15.0 grains per gallon (about 257 mg/L) across a range of 10.5 to 16.6, which is hard water, so rinse water left to dry on glass here will spot. Treat Allentown as hard in direction, variable by neighbourhood, and unresolved in magnitude until tested at the property.
| Hardness | 180–284 mg/L as CaCO₃ Printed in grains per gallon: average 15.0, range 10.5-16.6; LCA's own scale calls above 11 grains hard, as published by Lehigh County Authority / City of Allentown. |
|---|---|
| pH | 7.66 (range 7.41–8.17) |
| Alkalinity | 173 mg/L as CaCO₃ (range 70–211) |
| Iron | not detected |
| Manganese | not detected |
| Sodium | 50.8 mg/L (range 37.5–53.1) |
| Total dissolved solids | 412.5 mg/L (range 392–433) |
| Disinfectant | free chlorine |
| Source and treatment | Surface water, per the EPA SDWIS federal record · Powdered activated carbon, pre pH adjustment, coagulation, flocculation, rapid mix, sedimentation, rapid sand filtration and sludge treatment, pre and post chlorination, fluoridation, with an orthophosphate inhibitor and post pH adjustment · No softening step. |
Not in the report: corrosion index and chloride.
SOURCE · Lehigh County Authority, City of Allentown Division 2025 Water Quality Report (Secondary Contaminant Analysis), with the EPA SDWIS federal treatment record, PWSID 3390024 · How we source these numbers
The Lehigh Valley's limestone setting means the groundwater share deposits readily wherever it reaches glass, and irrigation is the usual route. Beyond that the calendar is ordinary mid-Atlantic — a spring pollen wave, autumn leaf drop through the older neighbourhoods, and winter road salt on lower panes from December into March.
PENNSYLVANIA SEASON BY SEASON →Allentown's system is run by the Lehigh County Authority under a long-term lease rather than by the city, a third operator type after municipal and investor-owned, and its 2025 report averages 15.0 grains per gallon of hardness. The supply draws on limestone springs, Little Lehigh Creek and the Lehigh River, and the report's own range of 10.5 to 16.6 grains shows that it varies. The logistics boom dominates the commercial market by area and prices on route efficiency; centre-city redevelopment is the smaller, higher-specification book.
The Lehigh County Authority operates Allentown's water system under a long-term lease of the city's water and sewer systems rather than the city running it directly. The Authority's 2025 report puts total hardness at 15.0 grains per gallon on average (10.5 to 16.6), which is hard water, and the concession arrangement is a third operator type alongside municipal and investor-owned.
The supply draws on two large springs, Little Lehigh Creek and the Lehigh River in limestone and dolomite country, and the report's hardness range of 10.5 to 16.6 grains shows how much it moves. Even sites that quote confident single figures for the city admit elsewhere that the data varies by neighbourhood and source.
One site gives three different Allentown values, 8.5, 13.2 and 8.2 grains per gallon, and admits on another page that it has no reliable figure. A number found online for Allentown may be contradicted by the same site.
Where the groundwater share is high, limestone-country water deposits readily as it dries, and irrigation overspray is the usual way it reaches glass. That marking bonds rather than sitting on the surface, so it needs an acid step rather than more effort with a cloth.
The warehousing and logistics boom along the valley corridor has built an enormous stock of modern low-rise commercial glazing in a short time. It is easy work priced on route efficiency and volume, and it now dominates the commercial market by area.
Centre-city redevelopment around the arena district has added a smaller book of higher-specification work with public-realm scheduling and event constraints, sitting on top of pre-war residential stock whose century-old putty lines will not take pressure.
The warehousing and logistics boom along the Lehigh Valley corridor has built an enormous stock of modern low-rise commercial glazing, and that work is priced on route efficiency and volume rather than on skill. Against it, the centre-city redevelopment around the arena district provides a smaller book of higher-specification work with scheduling constraints.
Nothing about the glass is difficult, and the honest position is that a careful owner will do well on modern stock. Two things justify paying: where the groundwater share is high, deposit bonds as it dries and needs an acid step rather than effort, and the centre-city stock carries pre-war sash whose putty lines have been through a century of freeze-thaw and do not tolerate pressure.
OPEN COST ESTIMATOR →2025 annual mean at the Allentown monitor, State Hospital Rear 1600 Hanover AVE, 4.4 km north-east of the city (EPA site 42-077-0004).
Largest air release: TRI-City Marble LLC, 4724 Springside CT (plastics and rubber), 1.6 km outside the city limits, 4,536 lb in 2024.
Allentown's water chapter lets the Bureau of Water Resources inspect wherever water is being wasted and shut the supply off if leaks go unrepaired after notice. It also penalizes anyone who draws from a hydrant or pump on premises that are not theirs without a bureau permit, and the occupier who lets them, so fill tanks only from the job site's own tap.
Allentown Code §633-6: investigation of waste and shutoff for refusal to repair · Allentown Code §633-12: using water from another's premises without a permit · checked September 2026
No one in Allentown may allow discharges that are not entirely stormwater into the city's storm sewer system, apart from listed discharges the city finds add no significant pollution or those a state or federal permit allows.
Allentown Code §538-36: prohibited discharges; exceptions · checked September 2026
When a building permit is sought for work in an Allentown historic district, the Historical Architectural Review Board decides whether the district rules apply and, if they do, reviews the work before a certificate of appropriateness can issue.
Allentown Code §328-10: consideration by HARB · checked September 2026
The Lehigh Valley industrial corridor (Allentown, Bethlehem, Easton) produces a fly-ash and limestone-dust fallout pattern on east-facing exposures within a few miles of the active and former cement plants and steel facilities. Concentration has declined since the 1990s industrial contraction but the cumulative residue on long-dwell glazing is still a working consideration on the historic properties.
Allentown runs on Lehigh County Authority / City of Allentown a mixed surface-and-groundwater blend at a published 180–284 mg/L (CaCO₃), averaging 257 — printed in grains per gallon: average 15.0, range 10.5-16.6; LCA's own scale calls above 11 grains hard.
Residential window cleaning in Allentown typically runs $8–13 per pane or $260–440 for a standard single-story exterior. The warehousing and logistics boom along the Lehigh Valley corridor has built an enormous stock of modern low-rise commercial glazing, and that work is priced on route efficiency and volume rather than on skill.
Allentown's drier, frost-free months are June and August and September, by NOAA's 1991–2020 normals for the Allentown International Airport station, where July brings the most rain. The calendar on this page marks June (after the April 29 bloom and after smoke season). Frost nights usually run from October 24 to April 20.
Not as the final rinse: Lehigh County Authority / City of Allentown publishes dissolved solids of 412.5 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 activated carbon, pre pH adjustment, coagulation and flocculation.
In Allentown the dominant residue patterns include limestone-groundwater irrigation overspray deposit on dark frames and spring pollen wave across the lehigh valley. The Lehigh Valley's limestone setting means the groundwater share deposits readily wherever it reaches glass, and irrigation is the usual route.
Nothing about the glass is difficult, and the honest position is that a careful owner will do well on modern stock. Two things justify paying: where the groundwater share is high, deposit bonds as it dries and needs an acid step rather than effort, and the centre-city stock carries pre-war sash whose putty lines have been through a century of freeze-thaw and do not tolerate…
Pre-1920 commercial core; revitalized PPL Center event-cycle commercial work. West End and Old Allentown Historic District have their own housing stock and glazing as well.
Just over the Pennsylvania line