What is a water-fed pole?

NGA's glass cleaning paper covers more than a cleaning solution and a squeegee. It also records a second technique, and a water-fed pole is the tool that carries it out.

Glass Technical Paper FB01-00 states that the International Window Cleaning Association "recognizes an additional glass cleaning technique being utilized by some professional window cleaning contractors," one that uses "pure water delivered to the glass surface using a specialized extension pole." A specialized extension pole is NGA's whole name for the tool; water-fed pole is a maker's name for it. The service page's section on pure water sets out NGA's paragraph in full, and the term itself is defined on the pure water glossary page.

On the glass, NGA describes "gentle agitation with a non-scratching (non-abrasive) brush" followed by a final pure water rinse, and says the rinse water "is generally allowed to evaporate from freshly cleaned surfaces." Nothing in that description wipes the glass dry afterward, and NGA's water rule follows directly from it: because the rinse is left to dry, the water has to meet a limit.

Taken from the water end forward, the tool starts with treatment, not with the pole.

NGA's rule for the technique is a number, 20 parts per million (PPM) or less of total dissolved solids, and it rules out tap water. What that TDS number measures has its own answer; here it is enough that the limit covers the wash water as well as the rinse.

NGA also names the equipment, saying effective water treatment "via ion exchange and/or reverse osmosis equipment should be used in conjunction with delivery & rinse methods at all times." Unger, a maker of these systems, describes one of its units as using resin bags "to filter basic tap water into pure, deionized water," and another as relying on reverse osmosis in a three-stage filtration process. Those are a maker's descriptions of its own products. The trade figure is NGA's 20 PPM.

Water quality "can be monitored with a handheld TDS or conductivity meter," in NGA's words, and NGA equates 40 microsiemens per centimeter with a TDS level of 20 PPM. The TDS entry defines the reading itself.

The pole is what carries that water up to the brush.

Unger's description of its own water-fed poles covers the parts: a telescopic pole, a flexible hose held in an integrated hose management system, and a brush at the head. The poles come in aluminum or carbon, and the maker gives lower weight as the reason for carbon, the material it describes for high access points.

A pole length is a product figure, not a trade one. NGA's paper sets no length and names only a specialized extension pole, so any reach printed on a maker's page describes that maker's product and nothing more.

At the head of the pole is the brush, and NGA's paper names its type.

NGA's words for it are "non-scratching (non-abrasive)," the brush that gives the glass gentle agitation before the final pure water rinse. The routine method NGA also publishes ends differently: a window cleaning squeegee removes all of the cleaning solution. In the pure water technique as NGA describes it, no squeegee pass follows, and the rinse is generally left to evaporate.

That missing squeegee pass is the reasoning behind cleaning second-story glass from the ground with a pole: nothing has to be wiped dry at the top of the window. It is also why a pane cleaned this way stays wet after the brush moves on, which has its own answer on why a window cleaner leaves the glass wet.