Bloomington softens its supply from 19 grains per gallon raw to about 5.2 grains finished, and keeps it noncorrosive to limit lead and copper leaching.
Bloomington softens its water centrally, from 19 grains per gallon raw to about 5.2 at the tap, which leaves it moderately hard; a tap rinse is fine except on dark or sun-hot glass. Hotel and office frontage along the commercial corridor keeps crews working through the winter, while homes wait for the July to September window, and a single-story exterior runs $240 to $430.
At about 5.2 grains, or roughly 89 mg/L, the water reaching a Bloomington window has already had most of its mineral taken out at the plant. That puts it in comfortable moderate territory: an ordinary tap rinse dries acceptably, and the deposit that does appear comes off easily if it is not left to bake. The number to ignore is nineteen grains. That is what the wells deliver before treatment, it is a real published figure, and it describes water no customer has ever received.
| Hardness | 89 mg/L as CaCO₃ Approximately 5.2 grains per gallon finished, in the city's own words, as published by Bloomington Utilities. |
|---|---|
| Sodium | 6.66 mg/L |
| Disinfectant | free chlorine |
| Source and treatment | City supply softened at the Bloomington plant, blended in distribution with softened Mississippi River water purchased from Minneapolis · Lime softening, reducing hardness from about 19 grains per gallon to approximately 5.2 · The plant softens. |
Not in the report: pH, alkalinity, corrosion index, iron, manganese, chloride and total dissolved solids.
SOURCE · City of Bloomington Water Quality Report, June 2026 (2025 results for Bloomington's plant and for water purchased from Minneapolis), with the EPA SDWIS federal treatment record · How we source these numbers
Winter is the loaded season, and the interstate and arterial corridors make it worse here than in a quieter suburb — salt spray carries further from fast roads than most people expect, and it reaches glazing well back from the carriageway. Spring thaw is the heaviest clean of the year. Summer brings irrigation film on ground-floor commercial glazing in the landscaped campuses. Autumn adds leaf and sap on the wooded western lots. Deep cold halts outdoor work.
MINNESOTA SEASON BY SEASON →Bloomington softens its water centrally and, unusually, publishes both ends of the process: lime softening takes the supply from nineteen grains per gallon raw down to about 5.2 grains finished, roughly 325 mg/L to 89. Having both numbers from one operator is rare and clarifying, because it shows how far apart a raw and a finished figure sit at the same plant — and only the finished one ever reaches a pane. The treatment is described plainly by the city: slaked quicklime in one of two 550,000-gallon contact basins forces calcium and magnesium out as floc, which is settled, removed, dewatered and used by Minnesota farmers as agricultural lime. Carbon dioxide, filtration, chlorine and fluoride follow, and the water is held noncorrosive to protect household plumbing. The city also buys finished water from Minneapolis, so taps here drink a shifting blend of softened groundwater and softened river water.
Bloomington is one of the small number of Minnesota municipal utilities that softens its water centrally, and the city says so as a selling point: it puts the figure at one of only twenty-four in the state, and tells residents they do not need to buy softeners of their own.
It also publishes both sides of that process, which almost no utility does. The city states that lime softening reduces hardness from nineteen grains per gallon to approximately 5.2 grains — roughly 325 mg/L down to about 89.
Those two numbers together are worth more than either alone, because they show how far apart a raw figure and a finished figure can sit at a single plant. Anyone quoting a hardness value for a softening city is quoting one of two very different numbers, and only one of them ever reaches a window.
The softening train is described in the city's own terms: slaked quicklime is mixed with raw water in one of two solids contact basins, each holding 550,000 gallons, and the reaction forces calcium and magnesium out of solution as insoluble floc that settles and is removed.
The removed floc does not go to waste. The city dewaters it and Minnesota farmers use it as a USDA-approved source of lime to stabilise pH in farm fields, which is an unusually tidy loop for a treatment byproduct.
Carbon dioxide is added afterwards in a recarbonation basin before filtration, chlorine and fluoride, and the finished water is deliberately held noncorrosive to keep lead and copper from leaching out of household plumbing.
Bloomington does not drink only its own water. It buys finished water from Minneapolis, which treats Mississippi River surface water, and the two softened supplies blend in the distribution system — so a given tap is drinking a mixture of softened groundwater and softened river water in proportions that shift with demand.
The commercial corridor is the economic anchor and it stabilises the year, since hotel and office frontage runs to facilities schedules that do not thin out in February the way residential demand does. On the residential side, softened water means no crew here needs to price treated rinse capacity, which keeps domestic quotes lean. Bluff properties carry an access premium that their storey count does not reveal.
Single-storey postwar housing on the eastern side is about as straightforward as this work gets, with softened water and accessible glass removing most of the difficulty. The valley bluff properties are the exception, because the ground behind the house falls away and a rear elevation that reads as two storeys from inside is considerably more from below. Hotel, retail and office glazing along the corridor is contracted work under facility access rules and is not a homeowner market at any level.
OPEN COST ESTIMATOR →2025 annual mean at the City of Lakes Building monitor, 309 2nd Ave. S., 17.1 km north of the city (EPA site 27-053-0966).
2025 annual mean at the Apple Valley monitor, 225 Garden View Drive, 11.9 km south-east of the city (EPA site 27-037-0470).
Largest air release: Consolidate Precision Products-Minneapolis Operation, 8701 Harriet AVE S (primary metals), inside the city limits, 42,580 lb in 2024.
In Bloomington only Public Works or Fire Department employees on authorized city work may operate a fire hydrant or otherwise interfere with the water system, unless the City Engineer or Utility Supervisor has given permission first. The next section bans unprotected cross connections to the city system, which covers hose-and-tank rigs.
Bloomington City Code §11.19: use of fire hydrants · checked September 2026
Bloomington's storm water chapter says no one may dump, drain or discharge pollutants or polluted water into the storm water management system, or let people under their control do it. Lawn watering and individual residential car washing are exempt; commercial washing runoff is not.
Bloomington City Code §16.10: illicit discharge detection and elimination · checked September 2026
Bloomington keeps a ranked Historical Register of burial-ground, Class I and Class II sites. The owner of a burial-ground or Class I site needs a certificate of appropriateness from the city to materially alter the exterior of an improvement there; Class II sites need one only for demolition. The city decides within three weeks.
Bloomington City Code §15.18: permits for prehistoric, Class I and Class II sites · checked September 2026
The defining late-winter Minnesota cleaning problem. Roof meltwater carries shingle-granule particulate, asphalt-plasticizer leachate, accumulated organic debris, and dissolved road-salt aerosol onto lower-sash positions. Sodium percarbonate prerinse plus citric acid lift required, with attention to dwell times and wash-water temperature. Chronic-ice-dam houses develop permanent staining without protocol intervention.
Lighter than Atlanta pine pollen but real on south- and east-facing exposures during peak weeks. Three-to-four-week window. Wet-only handling, light alkaline wash, no scraping.
Insect-residue load on lakefront residential glass within a few hundred yards of the major lakes (urban and cabin country). Chitinous-protein residue does not lift with plain water; needs slightly higher soap concentration.
Six-to-seven-month exterior weather without intervention on lakefront cabin stock produces moss, algae, and lichen layers on north-facing exposures under heavy canopy. Sodium percarbonate prerinse with longer dwell. Quaternary ammonium pre-treatment on the heaviest cases.
Smoke from BWCA-region or Canadian fires occasionally reaches the metro at concentrations that deposit measurable particulate on glass. Same chemistry and protocol as the Pacific Northwest smoke residue Easton Giordano describes.
Most relevant on commercial interior glass — building-entry storefronts collect salt-tracked residue on lower thirds throughout the winter. Twice-monthly cleaning sufficient with normal wash protocol.
At about 5.2 grains, or roughly 89 mg/L, the water reaching a Bloomington window has already had most of its mineral taken out at the plant. That puts it in comfortable moderate territory: an ordinary tap rinse dries acceptably, and the deposit that does appear comes off easily if it is not left to bake.
Residential window cleaning in Bloomington typically runs $8–13 per pane or $240–430 for a standard single-story exterior. The commercial corridor is the economic anchor and it stabilises the year, since hotel and office frontage runs to facilities schedules that do not thin out in February the way residential demand does.
Bloomington's drier, frost-free months are July to September, by NOAA's 1991–2020 normals for the Minneapolis/st Paul Airport station, where May brings the most rain. The calendar on this page marks July (after the May 11 bloom and after smoke season). Frost nights usually run from October 18 to April 23.
Yes, if the rinse is squeegeed off before it dries: Bloomington Utilities publishes hardness of 89 mg/L, between this site's two dissolved-solids flags. It draws on City supply softened at the Bloomington plant, blended in distribution with softened Mississippi River water purchased from Minneapolis.
In Bloomington the dominant residue patterns include centrally softened supply, reduced from 19 grains per gallon raw to about 5.2 grains finished and finished water held noncorrosive by design to limit lead and copper leaching.
Single-storey postwar housing on the eastern side is about as straightforward as this work gets, with softened water and accessible glass removing most of the difficulty. The valley bluff properties are the exception, because the ground behind the house falls away and a rear elevation that reads as two storeys from inside is considerably more from below.
Hotel, retail and office glazing at scale along the interstate and transit line, almost all of it post-1990 sealed curtain wall on contracted schedules. The largest concentration of commercial glass in the state outside the two downtowns. East Bloomington and West Bloomington have their own housing stock and glazing as well.
Just over the Minnesota line