Pure water window cleaning is a professional cleaning method that uses water filtered to remove all minerals and impurities, leaving glass completely residue-free when it dries.
No streaks, no water marks, and no chemical residue to attract further dirt. It is the industry standard for commercial window cleaning.
How Does Pure Water Window Cleaning Work?
Tap water is passed through a filtration system, typically a combination of reverse osmosis (RO) and deionisation (DI), which removes dissolved minerals, calcium, and impurities, reducing the total dissolved solids (TDS) in the water to zero.
This ultra-pure water is then delivered through a telescopic water-fed pole fitted with a soft brush head. The operative uses the brush to agitate the glass and frame, loosening dirt and grime.
The pure water simultaneously rinses the surface, and because there are no minerals left in the water, it evaporates completely clean; leaving no residue, spots, or streaks behind. No squeegee is needed.
What Is the Difference Between RO and DI Filtration?
Most professional pure water systems use two filtration stages in sequence. Reverse osmosis (RO) removes the majority of dissolved minerals and impurities from the tap water, typically achieving a reduction of around 95–99%.
Deionisation (DI) then polishes the water further, bringing the TDS level down to zero, meaning the water contains no dissolved solids at all.
Using both stages together ensures consistently pure water regardless of local water hardness. In London, where tap water hardness regularly exceeds 200–300mg per litre of calcium carbonate, a multi-stage system is essential to prevent mineral deposits on glass.
A single-stage system may not produce water pure enough to deliver streak-free results in hard water areas.
Why Is Pure Water Cleaning Better for Commercial Buildings?
For commercial buildings, pure water cleaning offers significant advantages over traditional soap-and-squeegee methods:
- No residue, longer-lasting results: Without soap or detergent on the glass, there is no sticky film to attract dust and pollution. Windows cleaned with pure water stay cleaner for longer than those cleaned with detergent-based methods.
- No hard water staining: In London, tap water leaves mineral deposits on glass when it dries. Pure water leaves nothing behind, eliminating the white, hazy film that makes recently cleaned windows look dirty again quickly.
- Frames and sills cleaned simultaneously: The water-fed pole and brush clean the full window including frames, sills, and reveals in a single pass, something a squeegee clean rarely achieves as thoroughly.
- Safe on all surfaces: No chemicals means no risk of damage to tinted glass, solar control coatings, uPVC or aluminium frames, or surrounding building materials.
- Environmentally friendly: No detergents, no chemical run-off, and no risk to surrounding planting or building facades.
For property managers dealing with recurring streaks or windows that get dirty quickly, switching to a contractor using a proper pure water system is often the most straightforward solution. Our guide on why windows get dirty after cleaning covers this in more detail.
How High Can Pure Water Window Cleaning Reach?
Water-fed pole window cleaning reaches up to 70 feet from ground level, covering most buildings up to around six or seven storeys.
For buildings that exceed this height, pure water delivery can be combined with abseiling window cleaning, cherry picker access, or BMU cradle systems, ensuring the method is right for every floor of the building.
This makes pure water the method of choice not just for low and mid-rise commercial buildings, but as part of a wider high-rise cleaning programme where it is used on the lower floors while rope access teams cover the upper levels.
For high-rise and skyscraper cleaning across London, visit our page to find out how we manage from ground level to roof.
How Long Does a Pure Water Window Clean Last?
Pure water cleans last longer than traditional methods because there is no soap residue on the glass to attract further dirt.
In a lower-pollution environment, results can last several weeks before re-soiling becomes noticeable.
In central London, pollution, airborne particulates, and construction dust mean windows will need cleaning faster regardless of the method used.
For buildings in these locations, a regular cleaning schedule of every four to six weeks produces the most consistently clean results.
Frequently Asked Questions
Standard water-fed poles reach up to 70 feet, covering buildings of approximately six to seven storeys. For taller buildings, pure water systems can be used in combination with rope access or high-reach equipment of up to 300ft.
The Professional Standard
Pure water window cleaning is the professional standard for commercial buildings, delivering streak-free, residue-free results that last longer than traditional soap-based methods.
For commercial properties in London, where hard water and pollution accelerate dirt, it is the most effective and practical cleaning method available.
At All Clean London, we use multi-stage pure water systems as standard across all our commercial window cleaning work, from ground-level retail units to multi-storey office blocks and residential towers across the city.
Request a free quote today and find out how pure water cleaning can keep your building looking its best.
