Unger Professional Cleaning Blog
Category Product Pure Water Cleaning Poles Sq 1

Commercial Outdoor Window Cleaning: Understanding the Science and Benefits of Pure Water Clean

While utilizing pure water is not new to commercial outdoor window cleaning, what some cleaning professionals may not yet realize is the science behind getting a faster, easier and safer end result. Pure water window cleaning, combined with water fed poles and brushes, allows professionals to more easily and efficiently operate thanks to the cutting-edge pure water technology available in the cleaning industry.

Cleaning with Tap Water v. Pure Water

Traditional window cleaning as its simplest includes a bucket of water, a ladder and squeegee. This approach may produce an acceptable result for small or internal jobs, but the tap water used as the basis for cleaning is ineffective when it comes to performing professional window cleaning jobs.

Tap water contains impurities, hopefully most of which are common and purposely introduced to provide safe drinking water. If you were to take a TDS meter and measure the level of impurities in tap water (measured in parts per million), you would likely see a reading of 100-200 mg/l, although safe drinking water can register higher values. While safe to drink, you don’t necessarily want to clean with tap water given its inherent impurities. Unless you’re able to remove 100% of the water during the window cleaning process, once the water evaporates, what’s left behind are these impurities – the culprits in causing undesirable spots and streaks.

Compare tap water to pure water which normally registers at .000-.001 parts per million, meaning it contains virtually no damaging minerals or sediments. When used in window cleaning, pure water, even if 100% of it is not removed from the windows, has minimal chance of leaving any residue behind. Not only does it leave behind no residue, but windows also stay cleaner for a longer period of time and the chance of spots and stains causing permanent damage to the glass over time is significantly minimized.

The Science Behind Pure Water

In its natural state, water contains impurities. Therefore, you have to create pure water through one of two water purification processes, or a combination of the two: reverse osmosis and deionization.

Reverse osmosis is the process of removing impurities (technically, ions) from water by forcing it through a filter (referred to as a membrane). Using pressure to force the water across a membrane, the impurities are left on one side of the membrane and the purified water on the other side.

Deionization, or sometimes referred to as demineralization, is the process of removing positive metallic ions (impurities), such as calcium and magnesium, and replacing them with hydrogen and hydroxyl, respectively forming pure water. Using either or a combination of these processes removes up to 99% of all the sediment and minerals from regular water and creates impurity-free water with virtually no contaminants.

The beauty of pure water, when used in window cleaning, is that when the pure water reaches a surface, the water immediately wants to try and return to its natural state (one with impurities). To do this, the pure water looks for dirt, dust and other particles to which it can adhere. Once the two elements meet, they are bonded together for easy removal during the rinse step of the process. During rinsing, with no dirt available for the pure water to bond with, the water will simply evaporate to leave a clean, spot-free, streak-free surface.

Telescopic Water Fed Poles

Pure water came to the attention of the commercial window cleaning industry when they realized the residue- and spot-free properties could modernize window cleaning. But it wasn’t until the development of the telescopic water fed pole that pure water exhibited its full potential to professional window cleaners and facility managers.

Extension poles were commonly used for cleaning starting in the 1970s, but it was the combination of pure water used with water fed poles in the 1990s that served to revolutionize commercial window washing. Pure water is pumped up through the telescoping poles, the attached cleaning brush scrubs the surface, and the stream of water from the pure water cleaning system rinses the surface clean. The windows are left to dry naturally leaving windows with a spotless, streak-free finish.

Reverse Osmosis - Pure Water Cleaning Diagram

Compare the practicality of the pure water window cleaning process which requires three pieces of equipment with traditional window cleaning and you’ll see additional advantages. Traditional window washing requires six-seven different components to clean, such as a ladder, squeegee, towel, bucket, etc. Without the functionality of a telescopic pole, you’re left with a cumbersome process that can pose unnecessary safety risks, slow down the speed of cleaning, and jeopardize the level of cleaning effectiveness.

Pure Water Window Cleaning v. Traditional Window Cleaning -Comparison Chart

Benefits of Pure Water Cleaning Systems

Clean and Efficient

Pure water gets windows remarkably clean by acting as a lubricant that breaks the bond between dirt and glass, allowing all the contaminants to be rinsed away. Negating the use of harsh cleaning chemicals, using pure water with water-fed poles has also proved to be extremely efficient in terms of labor, cost, and productivity.


OSHA standards and stricter health and safety laws concerning ladders have made the water fed pole system using pure water a superior choice for commercial outdoor window cleaning.  Because some poles are extendable up to 5 stories, workers can keep their feet on the ground for most jobs, eliminating a myriad of safety risks and minimizing worker injuries.

Cost Savings

Using a pure water window cleaning system simplifies the process of outdoor window cleaning, increases worker safety to help minimize workman’s comp, and eliminates the need for costly lifts and scaffolding. Also, since pure water creates a clean, residue-free glass surface, the time between cleanings can be lengthened—saving time and money.

Environmentally Friendly

One of the eco-friendliest features of pure water cleaning is that you can often forego using chemical cleaners that can be potentially harmful to the environment and workers. Using a water-fed pole and brush system, pure water acts a natural detergent and the runoff from the cleaning process doesn’t harm the plants or grass growing at the base of the building.

The Future of Pure Water Cleaning

As more facility managers and window cleaning professionals discover the benefits of science-backed pure water cleaning, it will continue as the new standard. Pure water cleaning delivers the cleanest, safest and most eco-friendly option for exterior commercial window cleaning. Through the years, the use of pure water cleaning has grown into new markets and continues to evolve as a cleaning solution to treat other surfaces, such as solar panels.  Before the use of pure water cleaning on solar panels, chemicals found in traditional cleaning solutions deteriorated and damaged its surface, and eventually, negatively impacted the life of the solar panel system. Since pure water is a natural detergent that is free of any chemicals, this worry is eliminated.

Where will we find pure water cleaning next? We’re excited to see.

Want to See How Outdoor Window Cleaning Professionals Utilize Pure Water in their Cleaning Systems? Watch the Video

Take a look at Unger’s comprehensive product line of professional window cleaning products.

Request a Demo Download Catalog