Portland water is soft to moderate at 7 to 68 mg/L, moss and algae film grow on north and shaded glass in the wet season, and street canopy stains in autumn.
Portland's water is soft, a blend of Bull Run water and some groundwater, so the tap is rarely the problem; moss and algae on shaded north walls and autumn stains from street trees are. The dry season is short and in demand, so June to September is the time to wash and summer slots book up. A single-story exterior runs $300 to $550, and the city's many old craftsman houses add time.
Two sources, an order of magnitude apart, feeding one city: the Bureau's own comparison table puts Bull Run water at about 7 mg/L of hardness, groundwater at 68, and a typical blend of 65 percent Bull Run and 35 percent groundwater at 28. Bull Run is protected mountain rainfall and is exceptionally soft; the Columbia South Shore well field is ordinary groundwater and is not. The Bureau samples and reports them separately, so the useful question here is which source is serving an address on a given day rather than what Portland's hardness is — and the well field is used mainly to cover summer demand and outages.
Figures by source, as reported.
| Hardness | 7–68 mg/L as CaCO₃ About 7 on Bull Run water alone, 28 in a typical blend with 35 percent groundwater, and 68 on groundwater alone, as published by Portland Water Bureau. |
|---|---|
| pH | 7.7–9.3 |
| Alkalinity | 17–105 mg/L as CaCO₃ |
| Iron | 0.0056–0.0811 mg/L |
| Manganese | 0.00261–0.0438 mg/L |
| Sodium | 11–12 mg/L |
| Chloride | 2.6–4 mg/L |
| Total dissolved solids | 44–140 mg/L |
| Disinfectant | chloramine |
| Source and treatment | Bull Run surface water, recorded by SDWIS as unfiltered under an avoided-filtration determination, with Columbia South Shore Well Field groundwater as a supplement · No filtration: post-chlorination with chloramines for residual maintenance, and caustic soda, soda ash and carbon dioxide for pH and alkalinity adjustment · No softening step. |
Not in the report: corrosion index.
SOURCE · Portland Water Bureau Supplemental Water Quality Data, April 2026 (Bull Run entry point, 12-month ranges; groundwater entry point, 3-year ranges), with the 2026 Drinking Water Quality Report and the bureau's test results page · How we source these numbers
The wet season does most of the work and not in the customer's favour. Eight months of rain keeps north and shaded elevations damp enough for moss, algae and the green film that is Portland's signature glass problem, and it re-establishes within weeks rather than months. The dry summer is the only reliable exterior window, which compresses the year's work into a short and heavily booked stretch.
OREGON SEASON BY SEASON →Portland runs two sources an order of magnitude apart — unfiltered Bull Run mountain rainfall, exceptionally soft, and the Columbia South Shore well field used mainly for summer demand — and the Bureau samples and publishes them separately three times a year. The Bureau states alkalinity adjustment is needed for the surface source but not the groundwater, which is the soft-aggressive signature in the operator's own words. Eight months of rain make moss and algae the defining problem rather than mineral, and the old multi-light housing stock makes per-opening time the right basis for a quote.
Portland runs two sources that are nothing like each other. Bull Run is protected mountain rainfall from a 102-square-mile watershed inside Mt Hood National Forest, closed to human entry and receiving 80 to 170 inches of rain a year; the Columbia South Shore Well Field is ordinary groundwater used mainly for summer demand and outages.
The Water Bureau samples and reports the two separately, publishing test results three times a year beyond the annual report, with Bull Run sampled at the Lusted Hill Treatment Facility outlet in April, August and November. Better-than-annual disclosure is rare and it means the seasonal picture is on the record rather than inferred.
The Bureau states that alkalinity adjustment is necessary for the surface source but not for the groundwater — an operator saying plainly that its mountain supply is soft enough to need conditioning. Soft, aggressive water is good news for glass and bad news for the plumbing behind it.
Bull Run is unfiltered, one of a small number of large surface supplies in the country allowed to meet federal standards without filtration. That status has an expiry date: the Bureau is designing and constructing a filtration plant, which will change the treatment train and possibly the finished water with it.
Eight months of rain make moss and algae the defining local problem rather than anything mineral. Green film establishes on north and shaded glazing within weeks, and it is a biological problem needing its own chemistry — scraping at established growth on an old frame takes putty and paint with it.
Portland's housing is old for a western city, and the craftsman and foursquare stock carries multi-light sash with high pane counts and century-old putty. Per-opening time rather than glass area is the right basis for a quote, and pressure of any kind is the wrong approach on those joints.
The season is short and everyone wants it, so summer capacity is worth more than rate for the rest of the year. Portland's housing is unusually old for a western city and the craftsman and foursquare stock carries multi-light sash with high pane counts, which makes per-opening time rather than area the right basis for a residential quote.
Very soft water means tap rinsing works, which removes the usual reason to hire someone. What replaces it is biological: moss and algae on glazing lines and frames are a different chemistry from dirt, and scraping at established growth takes putty and paint with it. The city's dense pre-1940 housing stock adds original sash and old putty that will not take pressure, which is the other genuine reason to pay.
OPEN COST ESTIMATOR →2025 annual mean at the Portland - Humboldt School (PHS) monitor, 4915 N Gantenbein Avenue, 2.9 km north-west of the city (EPA site 41-051-2010).
2025 annual mean at the Portland - SE Lafayette St (SEL) monitor, 5824 SE Lafayette Street, 5.8 km south-east of the city (EPA site 41-051-0080).
Largest air release: Mondelez Global LLC, 100 NE Columbia Blvd (food), inside the city limits, 66,349 lb in 2024.
Portland sets no everyday limits on hose use. Under City Code Chapter 21.80, the City Administrator may require water-use curtailment during a water shortage, an imminent shortage or an emergency that threatens the supply, weighing public health and safety, equity and economic conditions in deciding how far use must fall.
Portland City Code Chapter 21.80: Water Curtailment Policy · checked September 2026
Portland treats any discharge to the city storm sewer and drainage system that is not entirely stormwater, and not authorized by its code or permits, as an illicit discharge, and it specifically bars discharges with a visible sheen, a visible discoloration or a pH outside water-quality standards. Soapy wash water from cleaning glass should not be sent to a storm inlet.
Portland City Code Chapter 17.39: Storm System Discharges · checked September 2026
Portland's land-use decisions state that non-exempt exterior changes, window removal and replacement included, to a property in a historic or conservation district need historic resource review before the work, judged against the zoning code's approval criteria or the district's own guidelines. The code exempts some minor changes, so check with the city before assuming a window swap needs no review.
City of Portland, decision LU 13-241751: historic resource review for window replacement, Irvington · City of Portland, decision LU 15-129945: window replacement, Elliot Conservation District · checked September 2026
The defining west-side Oregon substrate problem. North-facing windows under heavy canopy build a green-black film of mixed photosynthetic organisms that needs different chemistry than a normal wash. Sodium percarbonate or a quaternary ammonium prerinse, dwell five to ten minutes, then squeegee. Bleach is the wrong tool — it strips, but it lifts paint and stresses gasket rubber.
Two sources, an order of magnitude apart, feeding one city: the Bureau's own comparison table puts Bull Run water at about 7 mg/L of hardness, groundwater at 68, and a typical blend of 65 percent Bull Run and 35 percent groundwater at 28. Bull Run is protected mountain rainfall and is exceptionally soft; the Columbia South Shore well field is ordinary groundwater and is not.
Residential window cleaning in Portland typically runs $10–16 per pane or $300–550 for a standard single-story exterior. The season is short and everyone wants it, so summer capacity is worth more than rate for the rest of the year.
Portland's drier, frost-free months are June to September, by NOAA's 1991–2020 normals for the Portland International Airport station, where December brings the most rain. The calendar on this page marks June (after the April 4 bloom and after smoke season and before frost). Frost nights usually run from November 19 to March 13.
Yes, if the rinse is squeegeed off before it dries: Portland Water Bureau publishes dissolved solids of 44–140 mg/L, between this site's two dissolved-solids flags. Iron, manganese, sodium and chloride all sit under this site's flags (highest: manganese up to 0.0438 mg/L). SDWIS records no filtration or softening for the system.
In Portland the dominant residue patterns include moss and algae film on north and shaded glazing through the wet season and organic staining from mature street canopy and heavy leaf drop. The wet season does most of the work and not in the customer's favour.
Very soft water means tap rinsing works, which removes the usual reason to hire someone. What replaces it is biological: moss and algae on glazing lines and frames are a different chemistry from dirt, and scraping at established growth takes putty and paint with it.
Pre-1900 industrial-loft heritage with post-2000 high-rise residential and curtain-wall commercial concentration. Northwest / Alphabet District and Eastmoreland have their own housing stock and glazing as well.
Just over the Oregon line