Pure water window cleaning requires a number of different components to ensure quality results.

Many window cleaners struggle to achieve good results when using purified water for a number of reasons:

• Some forget to rinse the window properly
• Application of the water to the window needs to be accurate
• PPM (parts per million) purity needs to be zero reading. Some work with readings of 15 or above and this results in “white spotting” residue left on the window
• They do not purify the water properly

Often the route cause is down to cutting corners with the installation of a purifying system in the first instance. This does not mean that you have to buy the most expensive system on the market, but it does refer to the fact that a water butt and a small domestic purifier (Reverse Osmosis Unit) will not be up to the task of producing quality water for window cleaning.

Individual Components

What does a standard pure water system consist of? What is the best setup for a domestic window cleaner?

The following are necessary components:

• Resin
• Waterproofed floor on thevehicle
• Varistream or equivalent100 psi pump to deliver water to the window
• Leisure Batteries
• Delivery Tank (situated in van or trailer)
• Water Fed Poles
• Hose reels
• Transfer Hose to deliver water from storage tank to delivery tank
• Reverse Osmosis Unit (See Reverse Osmosis below)
• 650-1000ltr Storage Tank

An individual domestic window cleaner would need a 100gpd (gallon per day) reverse osmosis unit with a storage tank situated in a garage or shed.

The actual reverse osmosis unit should consist of a pump for delivering the water from the mains tap to the system. Some systems will run just on mains water pressure. Then the system should consist of between 2 to 4 pre-filters. These remove sediment, carbon and limescale to name the major elements.

See below for a guide on how the water should pass through the reverse osmosis membrane.From here the water is pushed through the reverse osmosis membranes (these are blue in colour and are generally situated in a tube like casing that fits on the top of a standard system)

Then the water is pushed through the DI resin for final polishing.

Reverse Osmosis Membrane

The tube like casing that houses the RO membrane has a single feed on the top end and two exit points at the bottom end.

Pure water should be delivered through the single feed at the top end of the membrane.

Then water is pushed through the membrane. Waste water exits through the right hand tube (looking down with the holes facing upwards) and pure water exits through the left hand side.

From here the water is delivered to the DI resin. This then acts as a final polisher of the water.