The cleaning process
Most professional solar panel cleaners use a water-fed pole system: a telescopic pole (typically 6–12 metres) with a brush head fed by a supply of purified water. The operative works from the ground, guiding the brush across each panel in overlapping strokes while purified water rinses away loosened debris.
The purified water — produced by passing tap water through a reverse osmosis membrane and a deionisation filter — has a dissolved solids content close to zero. This means it evaporates from the glass without leaving any mineral residue, unlike tap water which leaves calcium and limescale deposits as it dries.
For installations not accessible from ground level, some cleaners use ladders, cherry-picker platforms, or rope-access equipment. Ground-based water-fed poles are the preferred method where access allows.
What is included in a good service
Pre-clean inspection. A professional cleaner should visually inspect the installation before starting — checking for obvious faults, loose panels, damaged frames, or cable issues. This takes a few minutes and means any problems are flagged before work begins.
Cleaning each panel. Each panel should be worked across methodically. A rushed clean that only wets the surface without brushing will not remove bonded deposits.
Post-clean condition check. After cleaning, a reputable cleaner will note whether any panels show signs of micro-cracking, delamination, discolouration, or connector issues, and report these to the homeowner.
Before and after output comparison. Some cleaners will note inverter output readings before and after the clean to demonstrate the efficiency recovery. This is not universal but is a sign of a thorough service.
How long does it take?
A standard domestic installation of 12–16 panels takes 45–90 minutes from arrival to departure, including setup, the clean itself, and a brief post-clean check. Larger systems, awkward access, or panels in poor condition take longer.
Same-day or next-day bookings are common with established local cleaners, particularly outside the spring peak (April–June) when demand is highest.
What a service does not include
Electrical testing or inverter diagnostics. Solar panel cleaners are not electricians. If your inverter is showing fault codes or you suspect an electrical problem, you need a solar installation engineer.
Roof repairs or tile replacement. Cleaners may notice damaged tiles and flag them, but repairs are outside the scope of a cleaning service.
Moss treatment for the roof. Some cleaners offer upsell services for roof moss removal or gutter cleaning. These are separate trades — be clear about what is included before booking.