What Do Professional Window Cleaners Put in Their Water? The Real Secrets Behind Crystal-Clear Glass

You’ve probably noticed how pro window cleaners leave glass so clear you almost risk walking face-first into it. No, it’s not magic—or some elite, trade-secret potion. It comes down to what they put in their water, and how they use it. You don’t need a chemistry degree or expensive gear to get close to pro results. You just need the right mix.

Most professionals keep things surprisingly simple. The most popular answer? A splash of basic dish soap. Not just any soap, though—usually one that’s clear, unscented, and doesn’t leave residue. Add that to a bucket of cold or lukewarm water, and you have the classic starter solution. Pros like it because it cuts through grime, keeps suds under control, and leaves no streaks behind. The secret isn’t what you buy, it’s how you use it: just a small squeeze—too much and you’ll be wiping forever.

• The Standard Professional Mix
• Dish Soap: The Unsung Hero
• Why Not Vinegar?
• Do They Ever Use Ammonia?
• Commercial Products vs Homebrew
• Pro Tips for Spotless Windows

The Standard Professional Mix

So what’s really swirling around in that bucket pros carry? Here’s the straight answer: most professional window cleaning jobs start with plain old water—no secret sauce. But here’s where it gets interesting: a few key add-ins make all the difference. The go-to is usually a basic, non-sudsing dish soap, such as Dawn or Fairy. Clear versions are popular since they don’t leave any dyes on the glass. For a standard five-gallon bucket, just a teaspoon or two does the trick. Any more than that, and you end up with streaks instead of shine.

Here's a classic recipe the pros rely on:

• 1 gallon of cold or lukewarm water (never hot—it dries too fast and can leave marks)
• 1 teaspoon of clear, non-scented dish soap

You might spot a bottle of isopropyl alcohol or a few drops of ammonia in some pro kits. Those are only for extra-tough jobs or greasy storefront windows. But for houses, the simple mix is usually enough. The combination breaks up mud, pollen, and greasy marks without hurting window frames or plants below.

To show it in numbers, here’s a quick reference on pro mixes:

The real key? Not overdoing it. A light touch with soap keeps the water slick, breaks surface tension, and stops any sticky buildup. That’s how you get sparkling glass, not sudsy streaks. Pro tip: skip fancy scented beers or miracle products. Almost every professional sticks with a version of this basic mix for dependable results.

Dish Soap: The Unsung Hero

When it comes to window cleaning, professional cleaners will almost always have dish soap in their arsenal. It’s the quiet champion in the bucket, often chosen over the fancy sprays lining store shelves. Why? Because dish soap checks off several must-haves in window cleaning: it breaks through greasy marks, lifts up stubborn dirt, and rinses off without a trace.

When you ask an experienced pro what soap they reach for, you’ll hear names like Dawn, Fairy, or Palmolive. They don’t just pick these brands out of habit—clear, unscented varieties kick butt at cutting through oily fingerprints and pollen without leaving behind suds or streaks. Plus, they’re easy to rinse, which is exactly what you want for a clean, streak-free shine. Just a few drops in a bucket (pro cleaners swear by about one teaspoon per gallon of water) get the job done. Add too much, and you wind up wiping away suds, not grime.

What makes dish soap so solid for glass cleaner purposes? It’s non-abrasive and pH-neutral, so you’re not risking your window seals or frames. Some cheaper options or scented soaps contain dyes and perfumes, which can make things worse by leaving a sticky film. Stick with clear and basic, and you can’t go wrong.

• Always mix dish soap with lukewarm water. Hot water can dry too fast, leaving streaks, and cold water might not loosen up grime as effectively.
• Use a microfiber cloth or professional squeegee. Old-school pros swear by squeegees for spreading and clearing soapy water cleanly.
• Avoid using too much soap; more isn’t better here. If the water feels slippery, not bubbly, you’re on the right track.

Here’s a quick look at why dish soap beats out other soaps for window cleaning:

No need to reinvent the wheel—if it works for the pros, it’ll work for you, too. Sometimes the simplest solutions are the best.

Why Not Vinegar?

You see tons of cleaning hacks online pushing vinegar as the answer to all things dirty, including windows. But ask any window cleaning pro, and you’ll find out most of them skip the vinegar. Sure, vinegar has natural cleaning power—it's slightly acidic, so it can dissolve some mineral spots or grime. But for day-to-day glass, it just doesn’t stack up to basic dish soap.

Here’s the real issue: vinegar can leave streaks, especially if you live in a spot with hard water. Plus, the strong smell isn’t something most folks want lingering in their house. Some types of window frames—think wood or certain metals—don’t play nice with acidic solutions, either. Over time, vinegar can eat away at sealants and damage finishes. That’s the opposite of what you’re going for, right?

Check out this quick comparison:

So, while vinegar sounds like a genius DIY move, it just isn’t what professionals trust for their glass cleaner routine. If you want streak-free windows and no weird side effects, stick to a tried-and-true dish soap solution. Save the vinegar for your salad dressing, not your windows.

Do They Ever Use Ammonia?

Ammonia sounds intense, right? It definitely packs a punch when used in window cleaning—but it’s not for everyday use. Most pros reach for ammonia with tough jobs, like windows coated in greasy handprints, smoke stains, or layers of city grime. Regular dirt and fingerprints? Not worth the hassle. But if there’s stubborn stuff that soap can’t touch, ammonia makes a difference.

Why isn’t ammonia used all the time? For starters, it smells strong and can irritate your eyes, skin, and lungs. Pro cleaners always work with good ventilation and, if they’re smart, wear gloves. It also doesn’t play well with tinted windows—the harsh chemical can damage the tint film, making it cloudy or even peeling off. That’s why it’s a no-go in cars with tinted glass or homes with special coated windows.

Here’s a typical pro-grade ammonia mix for really grimy glass:

• 1 gallon cold water
• 1/2 cup clear ammonia
• Optional: a small squeeze of mild dish soap (less is more)

Never mix ammonia with bleach or any cleaner containing chlorine. That combo releases toxic fumes—very dangerous, even for pros. Most window cleaners stick to ammonia only when nothing else cuts it, and always make sure everyone nearby knows it’s in use.

For regular outdoor jobs or homes, ammonia isn’t usually in the kit. The cleaning solution with just dish soap gets the job done well enough for most types of glass, saving the heavy chemicals for when it’s really needed.

Commercial Products vs Homebrew

This is the debate you hear all the time: should you go for store-bought window cleaning solutions, or just whip up your own mix at home? Professional window cleaners actually use both, depending on the job and the client’s requests—but there are some clear perks and drawbacks to each option.

Commercial window cleaning products, the stuff you see sold by brands like Unger, Ettore, or Windex, are made for convenience and results. They’re balanced to cut through grease, dust, and fingerprints without leaving steaks, and most include anti-static stuff to keep dust from coming back right away. Some formulas even have additives that help water sheet off, making drying faster. One cool stat: in a 2022 survey by the International Window Cleaning Association, about 60% of professional window cleaners said they kept a commercial solution in their van for quick jobs and high-traffic windows.

But there’s a catch—cost. If you’re cleaning your own house every few weeks, store-bought cleaners add up fast. And for basic dirt and smudges, most pros say commercial products don’t have some magic ingredient you can’t copy at home.

Here’s where the homebrew shine. The classic mix: a few drops of clear dish soap in a bucket of water, gets you 90% of the way to that pro-level shine. Some folks add a splash of vinegar for extra power against hard water stains, though most pros skip vinegar unless there’s a real calcium build-up, since it can leave a smell and streaks if overused.

One thing that’s the same for both: technique. Even the best cleaning solution won’t help if you don’t have a good squeegee and don’t dry the edges. That’s where the real pro touch comes in, whether you go commercial or homemade. If you want to match what the pros do, test both types and see what leaves your glass the cleanest!

Pro Tips for Spotless Windows

If you want your windows to look pro-clean, you’ve got to think like a professional. That means being particular with your gear, your window cleaning solution, and even the way you wipe glass. Here’s how the experts pull it off every day—and how you can copy their best cleaning solution tricks right at home.

• Use a squeegee: It might sound obvious, but it’s not just for show. Squeegees clear off the solution fast before streaks and dust have a chance to settle. Wipe the blade with a clean rag after every stroke to avoid dragging dirt along.
• Don’t clean in direct sunlight: Sun heats up glass, making the water evaporate insanely fast. That’s a recipe for streaks, no matter which glass cleaner you use.
• Tackle edges and corners first: Dirt and grime pile up here, so pre-wipe frames and corners with a damp microfiber cloth before hitting the main pane.
• Go top-to-bottom: Always work from the top of the window downward. That way, drips don’t mess up areas you’ve already cleaned.
• Swap out the water often: The dirtier your water, the more likely you’ll redeposit grime back onto the glass. Pros replace their buckets every few windows.

Want the numbers? A survey from the International Window Cleaning Association found that 77% of professionals say microfiber cloths beat paper towels or old rags for drying and touch ups. Less lint = cleaner windows. Here’s a quick look at what the pros use most:

If you’re still getting streaks, the soap ratio could be off. Pros use a tiny amount—about a tablespoon for every two gallons of water. Too much, and you’ll be chasing suds for an hour.

"The best window cleaning isn’t about fancy formulas. It’s about being picky with your tools and not rushing the job." – Mike Green, owner of Green’s Window Service, quoted in Clean & Clear Magazine, March 2023 edition.

Stick with these professional tips and you’ll have crystal-clear glass without calling in the pros—or pulling your hair out.