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ANOKA COUNTY, MN
Hard water stains in Andover, MN
Those white spots are minerals, left behind every time water dries on glass.
Andover water averages about 220 PPM of hardness. Wherever sprinklers or hoses reach the windows, that hardness builds up on the glass cycle after cycle, until the windows look cloudy even when they are clean.
Hard water stain removal is added to a window cleaning rather than sold on its own, and Carson Brenny, the owner, does the testing and the treatment himself, so the person who judges your glass is the person who treats it.

HONEST BEFORE WE START
We clean the glass, test one window and tell you what will lift. If the glass is etched, you will hear it from us first.
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Insured to $2M
Owner-operated
Based in Ham Lake
ANDOVER SPECIFICS
What hard water stain removal means in Andover
The local conditions that shape how Glass House approaches hard water stain removal in Andover, and the standards it holds to on every visit.
WATER
About 220 PPM, with summer iron
Andover's water averages about 220 PPM (parts per million) of hardness, above the 180 PPM level the USGS calls very hard. Its 2002 plant removes iron and manganese, but at peak summer demand untreated wells run and put both back into the system. When that water dries on a house, calcium stays behind as white spots on glass, and iron and manganese oxidize into orange and brown stains on siding, brick and concrete.
WATERING
Odd/even watering, May through August
Andover homes on city water follow an odd/even schedule by house number from May 1 through August 31, with no watering at any address from noon to 6 p.m. Every cycle that reaches the house leaves another thin layer of minerals where the spray dries, so a sprinkler head aimed at siding, glass or the driveway builds white spots and orange stains in the same place all summer.
WATER NEARBY
The Rum River and Crooked Lake
The Rum River forms Andover's western edge, Coon Creek runs through the city, and Crooked Lake lies on the Coon Rapids line. Kelsey Round Lake Park is also in Andover. Air near rivers, creeks and lakes holds more moisture, so roofs, siding and decks dry slowly after rain and dew. Algae, mildew and moss take hold on surfaces that stay damp, usually starting on the shaded north side. Glass near the water catches spray as well as irrigation, so spots there build up faster between cleanings.
HOMES
A median home built in 1994
The median Andover home was built in 1994, and about half of all homes date from the 1990s and 2000s. After about three decades of sunlight, vinyl siding, painted trim and gutters break down at the surface into a chalky film called oxidation. Rain running over the chalk leaves streaks, and the roughened surface gives dirt and algae a better grip. Glass left spotted for years is the most likely to be etched, and the test window settles it.
Sources: City of Andover, Water Department; USGS, Hardness of Water; City of Andover, Watering Restriction Policy and Water Department; City of Andover, Natural Resources and About Andover; Minnesota DNR, Crooked Lake; Point2Homes, Andover demographics (U.S. Census ACS 2019-2023).
HOW WE REMOVE IT
Clean first, test one window, then treat
Judging a hard water stain on dirty glass is guessing. The first cleaning removes everything else and leaves only the stain.
TINTED WINDOWS
Window tint never receives an abrasive, because an abrasive scratches the film. Tinted glass is cleaned with a non-abrasive applicator and a squeegee instead. That removes nearly all soiling, but hard debris, including bonded mineral spots, and anything behind the tint cannot be removed, so please mention tint when you book.
01
Clean the windows normally
Every window is cleaned by our usual method first, removing dirt, film and construction debris. What remains afterward is only the mineral stain, and that is the only reliable way to judge how far it has progressed.
02
Test one window
The treatment goes on a single pane first, applied directly to the glass, starting at the top and working down. You see the result on that window before any other pane is treated, and before you commit to the rest.
03
Agitate and dwell
The treatment is an acid, worked into the bonded scale with an abrasive. It then dwells for about 10 minutes, giving it time to work on the minerals before the glass is cleaned again.
04
Clean it again
The window then receives a second full cleaning, which removes the treatment along with the loosened minerals. Heavy scale sometimes takes a second application before the pane is finished.
05
A clear answer
If spots remain after two applications, the glass is etched, because the stains sat untreated too long. We tell you plainly and stop treating glass that cannot respond. It is also the best reason to deal with the next spots early.
FOR ANDOVER HOMES
What to know before your visit
SPRINKLERS
Aim away from glass
Adjust sprinkler heads so they water the lawn, not the windows. It is the single biggest fix, and the one that keeps treated glass clear afterward.
HOSES
Mind the overspray
Filling pools, washing cars and watering beds near windows all put hard water on the glass, so keep that spray pointed away from the windows as well.
ORANGE STAINS
Iron is a separate stain
Orange streaks near the windows are iron from the same water. They need an iron remover on the siding or concrete, and that remover never goes on glass.
WELLS
Check irrigation wells first
Homes with a private irrigation well water the lawn with untreated groundwater, so check those sprinkler heads first each spring and aim them with extra care.
HOW PRICING WORKS
An add-on, priced after a test window
YOUR HARD WATER JOB, AT A GLANCE
ADD-ON
Window cleaning first
From $240
The glass is cleaned normally so the stain can be judged
Test window
Always first
One pane is treated first, so you see the result
Hard water stain removal
Quoted
Added once we can see how far the stains have progressed
If the glass is etched
Honest answer
You will hear it plainly, before the rest are treated
Builders and commercial sites
In person
Quoted in person by Carson
Added to any window cleaning
Test first
Hard water stain removal is quoted as an add-on to a window cleaning, because its severity can only be judged on clean glass. Carson tests one window first and tells you what will lift before the rest are treated. Window cleaning package minimums start at $240.

THE OWNER
The person who quotes your home does the work
Glass House is owned and run by Carson Brenny, with no crews, subcontractors or handoffs. He grew up in Ham Lake, went to Blaine High School and has worked full-time in exterior cleaning for six years. The person who quotes your home is the person who arrives, does the work and walks it with you at the end.
Every job receives the gentlest method that will do the work, because too much force or too strong a mix can cause damage that no cleaning undoes. Every homeowner receives a clear explanation of what is on the house, why the method was chosen and what cleaning can and cannot fix, before any money is spent.
IN CARSON'S WORDS
“It's my neighbors' homes: their biggest investment, one of the places they spend the most time, and where the people they care about most live. It's something everyone should enjoy, and I believe that.”
Carson Brenny, owner
WHAT IS INCLUDED
What hard water removal includes and excludes
Hard water treatment removes bonded mineral scale from glass. Damage within the glass, and the water that caused it, fall outside what cleaning can change.
INCLUDED
In every hard water treatment
• A normal window cleaning first, so only the stain remains
• One test window, so you see the result before we continue
• An acid treatment from the top down, worked in with an abrasive
• About 10 minutes of dwell, then a second full cleaning
• A second application on heavy scale
• A clear answer if the glass is etched
NOT INCLUDED
Outside hard water removal
• Etched glass, which only polishing or replacement can fix
• Abrasives on tinted glass, which receives a non-abrasive clean
• Prevention of new spots, which depends on sprinkler aim
• Iron stains on siding and concrete, a separate service
EQUIPMENT AND METHODS
Acid on the stain, pure water after
The treatment is an acid, applied straight onto the glass and worked in with an abrasive. The cleanings before and after use our standard methods: a T-bar and squeegee by hand, or a water-fed pole that rinses with 0 PPM pure water and reaches up to six stories, so the work leaves no new mineral spots behind.
ANDOVER QUESTIONS
Hard Water Stain Removal in Andover: FAQ
How hard is Andover water?
Andover city water runs about 220 PPM of hardness. PPM means parts of dissolved minerals per million parts of water, and the USGS calls anything over 180 PPM very hard. Water that hard leaves a visible layer each time it dries on glass, so spots build quickly wherever sprinklers reach the windows.
Do you serve all of Andover?
Yes, every neighborhood in Andover. Glass House is based in Ham Lake, and Andover is part of its regular north metro service area, so there is no trip fee. Carson quotes, cleans and walks every job himself, wherever in Andover your home is.
What causes the white spots on my windows?
They are calcium and other dissolved minerals left behind when sprinkler or hose water dries on the glass. The water evaporates, the minerals stay, and every watering cycle adds another layer. North metro water is very hard, and private wells bypass any city treatment, so spotting is common wherever spray reaches a window.
Can every hard water stain be removed?
No. Surface film comes off with a normal cleaning, and bonded scale usually lifts with our acid treatment. Etched glass is different: the minerals have damaged the glass itself, and no cleaner can reverse that. Etched glass can only be professionally polished or replaced, and we will tell you if that is what we find.
Why do you need to clean the glass before quoting?
Severity only shows once the glass is clean. Dirt, film and debris hide how far the minerals have progressed, so we clean the windows normally, test one pane and price the treatment from what we actually see. That way the quote reflects your glass rather than a guess.
Will the spots come back?
They will if the water keeps reaching the glass. The treatment removes the minerals that are there, but a sprinkler head that still hits the window lays down a new layer with every cycle. Re-aiming the heads toward the lawn is what keeps the result.