Billings glass on the east and south corridor picks up refinery film, sandstone grit blows off the Rimrocks, and water runs 52 to 233 mg/L hard.
Billings water swings from soft to hard through the year, so hardness depends on the date more than the address, and it is at its hardest in late summer. Refinery film coats the east and south corridor and sandstone grit blows off the Rimrocks; July to September is the working window. The short season and late-summer water make the same job cost more to finish properly, and a single-story exterior runs $240 to $400.
A range this wide means hardness is a date in Billings rather than a property of the address. At the bottom of it the supply behaves like a soft city and tap rinsing finishes clean; at the top it is firmly hard and will spot anything left to dry. The correct question here is never how hard the water is, but how hard it is this month.
| Hardness | 52–233 mg/L as CaCO₃ Spans soft to hard — the low end sits below the 60 mg/L soft boundary and the high end well into the hard band, as published by Billings Water. |
|---|---|
| pH | 7.47–8.39 |
| Alkalinity | 44–170 mg/L as CaCO₃ |
| Sodium | 5.9–35.5 mg/L |
| Chloride | 4.8–15.5 mg/L |
| Total dissolved solids | 74–286 mg/L |
| Disinfectant | uv + chlorine |
| Source and treatment | The Yellowstone River in full, drawn through two intakes; the city's own susceptibility analysis rates the river at low risk · Coagulation, flocculation, sedimentation, rapid sand filtration, ultraviolet disinfection and chlorination. No softening step appears in the operator's description. · No softening step. |
Not in the report: corrosion index, iron and manganese.
SOURCE · City of Billings, 2019 Water Quality Report, secondary-standards table (billingsmtpublicworks.gov), with the 2017 edition of the same table (copy posted by MSU Billings Facility Services); the 2014 edition gives hardness 48 to 216 · How we source these numbers
Interval tracks river flow. Through spring runoff the supply contributes almost nothing and the calendar is set by wind-blown grit and pollen; from August into winter the mineral load climbs and spotting returns on its own schedule, independent of how dirty the glass actually is. A frequency agreed in June will look wrong by September for reasons that have nothing to do with the work.
MONTANA SEASON BY SEASON →Billings publishes hardness as a range, not a point: 52 to 233 ppm across the year. That 4.5-fold swing is the fact to plan around — Yellowstone River water softens under spring snowmelt and hardens through late-summer and winter low flow, so the hardest water of the year arrives in the busiest weeks of the exterior season. Add the refinery corridor's oily film, which needs surfactant rather than pure water, and Billings rewards crews who carry two chemistries instead of one.
Billings runs on Yellowstone River surface water and the city publishes what that does to hardness: a range of 52 to 233 ppm, with the 2014 edition of the same table reading 48 to 216. Nothing else on this site swings that far inside one city. A single annual number would misdescribe most of the year here, which is presumably why the operator does not print one.
The mechanism is snowmelt. Spring runoff dilutes the river and delivered hardness drops toward the bottom of that range; by late summer and through winter low flow it climbs back toward the top. The same rinse habit that passes in May will spot in September on the same building, and the crew that does not know the range will blame its equipment.
Because the hard end lands in late summer, the worst spotting season coincides with the busiest exterior season. Plan for a final deionised or filtered rinse on August and September commercial work even where tap rinsing was passing in June.
The city publishes a monthly water quality summary for both the Yellowstone River and the finished product, not only an annual report. That is rare, and it means a crew here can check the current state of the supply before a large job rather than working from a yearly average — the most actionable water disclosure available in any city on this site.
Billings is Montana's refinery city, with major petroleum refining on the east and south side of the river. Glass downwind carries an oily particulate film that behaves nothing like mineral scale — it needs a surfactant step first, and a pure-water pass over it just moves the film around.
The Rimrocks — the Eagle Sandstone cliffs standing several hundred feet above the north side — shed fine sandstone grit that the wind carries down over the neighbourhoods below. It is silica, it is angular, and it is the main scratch risk in the city.
At roughly 3,100 feet with dry air and high UV, rinse water flashes off fast. Working a large commercial pane in direct afternoon sun here is how streaks get locked in; the practical fix is to chase shade around the building rather than to work the elevation in order.
Billings sits in a severe hail corridor, and a single storm resets the workload for the whole city. Post-hail demand arrives as a spike rather than a trend, and the first pass on any hailed building should assume grit is embedded in screens and frame channels.
Season is the dominant driver — a short high-desert exterior window concentrates the year's work and the late-summer peak coincides with the hardest water, so the same job costs more to finish properly in September than in May. Hail is the other one: a single storm converts the whole city into restoration work at once, and post-storm pricing reflects both the surge and the embedded-grit handling that follows it.
The spring window is genuinely forgiving and a homeowner working in May or June on accessible glazing will get a clean result with ordinary equipment. The trap is assuming that carries. By late summer the same method on the same windows leaves mineral spotting, and the refinery corridor's oily film needs a surfactant step that no amount of care with a squeegee substitutes for. Anything on the Rimrock side also carries a real scratch risk from embedded silica grit, which is the one mistake here that cannot be undone.
OPEN COST ESTIMATOR →2025 annual mean at the Billings Lockwood monitor, 2320 Old Hardin Rd, 10 km east of the city (EPA site 30-111-0087).
Largest air release: Jupiter Sulphur LLC, 2201 7TH AVE S (chemicals), inside the city limits, 144,821 lb in 2024.
Billings runs its own water utility, and its code says no one may open into, connect to or use the city water supply system without first getting a written permit and posting the bond the code requires, so a hydrant hookup for a wash rig needs the city's sign-off; tampering with system equipment without authorization is a separate prohibited act.
Billings City Code Sec. 26-115: permit required for connection, extension or use · Billings City Code Sec. 26-117: prohibited acts · checked September 2026
Billings makes it unlawful to discharge into its storm sewer system any materials, pollutants and polluted water included, that contribute to a water quality violation or could put the city in breach of its state discharge permit.
Billings City Code §28-301: prohibitions of illicit discharges · checked September 2026
In a Billings historic district, every building or exterior-remodeling permit (interior work excepted) goes to the Yellowstone Historic Preservation Board, which holds a noticed public hearing and advises the city to approve, modify, deny or delay it within 30 days; silence counts as approval. Budget that time before replacing storefront or window glass.
Billings Code §6-712: historic preservation board review of certificates of appropriateness · checked September 2026
Wildfire-smoke residue heavy in active fire seasons. The 2017, 2018, 2021, and 2024 fire seasons each produced extended residue exposure on residential and commercial statewide. Operators serving statewide residential carry wildfire-smoke residue handling as part of the routine fire-season operating practice.
High-elevation UV exposure accelerates IGU seal degradation. Document seal-degradation indicators on each residential visit. Same handling framework as Sun Valley and Park City.
Extended citric pre-treatment (4-6 minutes) plus citric-rinse finish required. Verify chemistry on individual properties.
Billings runs on Billings Water lake or reservoir surface water at a published 52–233 mg/L (CaCO₃) — spans soft to hard — the low end sits below the 60 mg/L soft boundary and the high end well into the hard band. A range this wide means hardness is a date in Billings rather than a property of the address.
Residential window cleaning in Billings typically runs $8–13 per pane or $240–400 for a standard single-story exterior. Season is the dominant driver — a short high-desert exterior window concentrates the year's work and the late-summer peak coincides with the hardest water, so the same job costs more to finish properly in September than in May.
Billings's drier, frost-free months are July to September, by NOAA's 1991–2020 normals for the Billings Logan International Airport station, where May brings the most rain. The calendar on this page marks July (after the May 10 bloom and after smoke season). Frost nights usually run from October 7 to May 4.
Yes, if the rinse is squeegeed off before it dries: Billings Water publishes dissolved solids of 74–286 mg/L, between this site's two dissolved-solids flags. Water left to dry leaves mineral scale; fresh spots lift with a mild acid. A deionising cartridge yields about 35% of what it would on 100 mg/L water. It draws on the Yellowstone River in full, drawn through two intakes.
In Billings the dominant residue patterns include refinery particulate and oily film (east and south corridor) and rimrock sandstone grit. Interval tracks river flow.
The spring window is genuinely forgiving and a homeowner working in May or June on accessible glazing will get a clean result with ordinary equipment. The trap is assuming that carries. By late summer the same method on the same windows leaves mineral spotting, and the refinery corridor's oily film needs a surfactant step that no amount of care with a squeegee substitutes for.
Montana's densest commercial core, including the tallest building in the state. Genuine high-rise work — rope access or lift — which almost nowhere else in Montana offers. Under the Rims and The Heights have their own housing stock and glazing as well.
Just over the Montana line