What is pure water? Does pure water window cleaning work? How impure is other water?

PURE water is a collective term used to describe water that has been filtered or processed to remove impurities and contaminants. Other names some use are deionised or distilled water. The resulting pure water is perfect for window cleaning and is also environmentally friendly.

What is pure water?

Pure water has been mechanically filtered from its original state as tap water or drinking water. By passing this water through pre-filters and a semi-permeable membrane, it reduces impurities by 97-98%. This process is called reverse osmosis. Rather than absorbing, this process separates molecules and particles from the water. Its purity can be measured in ppm (parts per million). Original tap water can contain 250-300 particles of chemicals or contaminates per million parts of water, depending on which part of the country you live in.

Although that may seem low (1ppm is equivalent comparatively to 32 seconds out of a year or 1 mm of error per km of distance traversed) it is noticeable. Wash your car or pressure wash your patio and you’ll see water marks and staining on glass surfaces as it evaporates. The trace elements remain and are highly visible.

After reverse osmosis the pure water reading can be as low as 5-10 ppm of impurities. A final “polish” is applied by passing the water through ion-exchange resin. The result is 0 ppm – pure water!

Does pure water clean windows?

Window cleaning benefits greatly from pure water. The water not only dissolves dirt and dust but also washes it away. Window frames, doors, solar panels, signs etc can all be cleaned,. See our gallery for window cleaning videos and photos. Once thoroughly scrubbed and washed the only thing left on the glass is pure water. Once evaporated the glass is left sparkling clean.

In fact, we find in using this water we need to clean less often and would therefore recommend 8 weeks between visits.

How impure is other water?

Interested in testing your own water? We can test it for you if you’re interested. However Bristol Water has an online water checker, all you need is your postcode.

Below are some examples of the levels of impurities in different types of water.