I spend a lot of time around window cleaning.
As the Content Manager for Squeegee Squad Tulsa, I’m regularly filming crews, talking with technicians, visiting commercial properties, and researching the questions property managers ask about maintaining their buildings.
But I want to make something clear before we get into this.
I’m not a professional window cleaner.
I’m not the person hanging off the side of a building, operating a water-fed pole, or determining what restoration process a piece of glass needs. What I can do is take what I see in the field and compare it with information published by people who actually work in the industry.
How do you know when a building actually needs its windows cleaned?
There isn't necessarily a universal calendar that works for every property. Location, landscaping, traffic, irrigation, construction, weather, building design, and dozens of other variables can affect how quickly glass becomes dirty.
Instead of relying entirely on a date on the calendar, there are several warning signs property managers can watch for.
Here are seven of them.
(All information is sourced from the internet and other reputable sources)
1. You Can See a Haze Across the Glass
This is probably the easiest sign to recognize.
Windows don't always become noticeably dirty overnight. Instead, dust, pollen, moisture, and other contaminants gradually accumulate until the glass begins developing a dull or hazy appearance.
The interesting part is that people who see the building every day may not notice the change immediately.
It happens gradually.
Eventually, you may look across the building from a parking lot or walk toward the entrance at the right time of day and suddenly notice that the glass doesn't look as clear as you remember.
If you can clearly see a film across the glass from a distance, the cleaning probably isn't early.
At that point, the buildup has become visible enough to affect the appearance of the property.
Water spots deserve a little more attention than ordinary dirt.
According to Window Genie, hard water stains develop when mineral-containing water dries on glass and leaves deposits behind. Calcium and magnesium are among the minerals commonly associated with this buildup.
One of the most common sources around commercial properties is irrigation.
A sprinkler repeatedly hitting the same section of glass may not seem like a major problem at first. But the water evaporates while minerals remain behind.
Do that repeatedly and the spotting can become much more noticeable.
Professional window cleaner Justin Rafael Orloff also explains in his guide to professional hard water stain removal that mineral deposits are fundamentally different from ordinary dirt and may require a different removal process.
That distinction matters.
If you're seeing white spots, cloudy patches, or mineral-looking residue that doesn't disappear with normal cleaning, you may be looking at something beyond ordinary dirt.
That is a good reason to have the glass evaluated rather than simply waiting until the next scheduled cleaning.
Walk through your main entrance and look at the doors from an angle.
You might be surprised.
Commercial entrances are constantly touched by employees, customers, vendors, delivery drivers, and visitors. Even when the rest of a building's windows still look acceptable, entrance glass can quickly collect fingerprints and smudges.
And this glass matters.
It's often some of the first glass a customer sees before entering the building.
A property doesn't necessarily need every window cleaned simply because one entrance door has fingerprints all over it. But consistently dirty entrance glass can be a sign that your current maintenance frequency isn't matching the amount of traffic your property receives.
Your cleaning schedule should reflect how the building is actually used.
A busy retail property and a low-traffic office building probably shouldn't automatically be treated the same.
This is something worth looking for during your next walk around the property.
Check the lower sections of the windows.
Depending on the building, these areas may be exposed to sprinkler overspray, landscaping debris, soil, parking lot dust, rain splash, or runoff from surrounding surfaces.
In some situations, you may notice that the majority of a window looks relatively clean while the bottom section has considerably more buildup.
That pattern can tell you something.
The problem may not simply be that the entire building is "dirty." There may be a specific environmental source repeatedly contaminating certain sections of glass.
For example, Serv1sland's guide to mineral deposits on glass notes that irrigation overspray, roof or facade runoff, and repeated drying can contribute to deposits on glass.
Identifying the source matters because cleaning the window without addressing the source may mean the same problem returns.
Construction changes things.
Even if the work isn't happening directly on your property, nearby construction can introduce additional dust and airborne debris into the surrounding environment.
The same idea applies when your own building undergoes exterior work.
Painting, concrete work, landscaping projects, facade repairs, roofing, and other maintenance can leave glass considerably dirtier than it would become under normal conditions.
This is one reason I wouldn't rely exclusively on something like:
"We clean the windows every six months."
Six months may work perfectly during one part of the year and poorly during another depending on what has happened around the property.
Your building doesn't know what your maintenance calendar says.
If conditions around the property change, the cleaning schedule may need to change with them.
This one is interesting because rain often gets blamed for making windows dirty.
But water itself isn't always the entire problem.
If glass already has dust, pollen, minerals, or other material sitting on the surface, moisture can make existing contamination much more noticeable once everything dries.
You may suddenly see spotting, streaking, or patterns across the glass that weren't as obvious beforehand.
Hard water provides a good example of what happens when mineral-containing water evaporates. The water disappears while dissolved minerals can remain behind on the surface. Window & Door's explanation of hard water stains describes how calcium and magnesium deposits can create the chalky or hazy appearance commonly associated with water spotting.
So if every rainstorm seems to reveal how dirty the windows are, the rain may be exposing a maintenance issue that was already developing.
This might be the simplest sign on the entire list.
Ask yourself:
When were these windows last professionally cleaned?
If the answer requires searching through old invoices, asking multiple employees, or saying, "I honestly don't know," there probably isn't much of a maintenance system in place.
That's where properties can unintentionally fall behind.
Window cleaning becomes something that happens when someone finally notices the glass looks bad instead of something that is planned as part of normal building maintenance.
And once the windows visibly look neglected, you're reacting to the problem instead of staying ahead of it.
After spending time around this industry, I've realized that this probably isn't the best question.
Almost every exterior window is going to have something on it.
The better question is:
Has the buildup reached the point where it's affecting the appearance or maintenance of the property?
That's different for every building.
A storefront next to a busy parking lot may need attention much sooner than an office building surrounded by landscaping. A property with sprinklers hitting the glass may develop mineral spotting while another property never experiences that problem.
There isn't one schedule that makes sense everywhere.
Walk around your property.
Seriously.
You don't need to understand professional window cleaning to perform a basic visual inspection.
Look at the building from the parking lot. Walk toward the entrance like a customer would. Look at the glass from different angles. Check around sprinklers and landscaping. Look at lower windows. Check entrance doors. Pay attention to cloudy areas and unusual spotting.
Then compare what you're seeing with your current cleaning schedule.
If the windows consistently look bad weeks before the next service, your cleaning frequency may be too low.
If they still look great when the next cleaning arrives, you may already have an appropriate schedule.
And if you're seeing mineral deposits, unusual staining, scratches, or something that doesn't look like ordinary dirt, that's where I'd stop guessing and ask someone who actually works with glass professionally.
Because again, I'm not a professional window cleaner.
But after spending enough time documenting the work, researching the industry, and watching what our crews encounter on commercial properties, one thing has become pretty obvious:
The best time to think about window cleaning is usually before everyone starts noticing the windows need to be cleaned.
Treshaun Williams is the Content Manager for Squeegee Squad Tulsa, where he creates educational resources that help commercial property owners and facility managers make informed decisions about window cleaning and building maintenance.
Working closely with experienced technicians throughout Oklahoma, Tre focuses on providing transparent, practical information about cleaning schedules, pricing, glass restoration, and the environmental factors that affect commercial properties.
Tags: Commercial Window Cleaning, Window Cleaning, Building Maintenance, Property Maintenance, Facility Management, Property Managers, Commercial Property Care, Window Maintenance, Hard Water Stains, Dirty Windows, Preventative Maintenance