Solar Panel Cleaning: Do Panels Need It, How Often and How to Do It Safely

Do solar panels need cleaning? Usually not often. In most of South Australia and Victoria, regular rain washes off the everyday film of dust, so solar panel cleaning is only worth paying for when something specific is blocking the light, such as bird droppings, a dust storm, heavy pollen or lichen. This guide explains how to tell when your panels need a clean, how to do it safely from the ground, and when to call a professional instead.

Do solar panels need cleaning in Adelaide and Melbourne?

For most homes, the answer is “rarely”. The Australian Government’s Solar Consumer Guide notes that most panels are installed on a slope of at least 10 degrees, so they should self-clean when it rains. It adds that cleaning may be needed in some situations, such as very dusty locations.

Adelaide is Australia’s driest capital city, so dust can build up over a long, dry summer. Even so, SolarQuotes’ long-running analysis estimates that for most Australian households, cleaning panels twice a year would only improve average output by about 2%. Melbourne’s more frequent rain keeps panels cleaner still.

Where cleaning does make a real difference:

• Bird droppings. A single dropping can shade part of a cell. Because cells are wired in series, one shaded patch can drag down the output of a whole panel or string.
• Flat or low-tilt panels. Panels laid almost flat (common on carports and some commercial roofs) don’t drain well. Dirt collects along the lower frame edge.
• Dusty locations. Homes near unsealed roads, quarries, farms, building sites or the coast (salt spray) can build up grime that rain won’t shift.
• Lichen and moss. Shaded, damp roofs in Melbourne’s hills and outer suburbs can grow lichen along panel edges.
• Smoke and pollen events. Bushfire smoke and heavy spring pollen can leave a sticky film.

This article is part of our complete guide to solar panel maintenance, repairs and performance, which covers servicing, monitoring and repairs in more detail.

How much output do dirty solar panels lose?

It depends on the type of dirt, not just the amount. An even film of dust spreads the loss across every cell and costs relatively little. Concentrated grime, such as droppings or a strip of dirt along the bottom edge, can shade individual cells and cause much larger losses.

Here’s a simple worked example. A 6.6kW system in Adelaide produces roughly 28 kWh a day on an annual average (about 4.2–4.4 kWh per kW installed). A 2% soiling loss is about 0.56 kWh a day, or roughly 200 kWh a year. If you use most of that solar yourself instead of buying power at around 40c/kWh, that’s about $80 a year. If most of it is exported at a 3–5c feed-in tariff, it’s under $10. A professional clean for a 15-panel system often costs more than that.

So, for a typical home, cleaning is about fixing a specific problem, not a routine chore. Your solar monitoring app is the best way to tell the difference.

How do I know if my panels need cleaning?

1. Look from the ground. Use binoculars or your phone’s zoom. Check for droppings, leaves, lichen or a brown film along the bottom edge.
2. Compare sunny days. In your monitoring app, compare a clear day this month with a clear day at the same time last year. A gradual drop of more than about 5–10% with no new shading is worth investigating.
3. Check after rain. If output bounces back after a heavy shower, dust was the cause and nature has already done the job.
4. Rule out other causes. New shade from trees or a neighbour’s extension, a faulty inverter or a tripped isolator can look like “dirty panels”. Our guide to common solar problems walks through these checks.

How to clean solar panels safely

Safety comes first. The Solar Consumer Guide says only a qualified person should clean your panels, because it can be dangerous to do it yourself. Falls from roofs and ladders are a real risk, and a solar array is a live electrical system whenever the sun is shining. It cannot be “switched off” at the panels.

If your panels are on a single-storey roof and you can reach them safely from the ground, a gentle rinse is low risk. Follow these rules:

• Stay on the ground. Don’t climb onto the roof or lean ladders against gutters. If you can’t reach from the ground, book a professional.
• Clean early in the morning or on a cool, overcast day. Cold water on hot glass can cause thermal stress, and water evaporates fast on hot panels and leaves spots.
• Use a garden hose on a gentle spray. Let water fall on the panels like rain. Don’t use a pressure washer or a concentrated jet, which can damage the seals between the glass and frame.
• Use a soft, non-abrasive brush or squeegee on an extension pole for stubborn marks. Choose a non-conductive pole and keep it well clear of power lines and the service cable to your house.
• Use clean water only. Skip detergents, solvents and scourers. They can damage anti-reflective coatings, may breach the panel manufacturer’s cleaning conditions, and can end up in your rainwater tank. Very hard bore water can leave mineral spots.
• Don’t spray the inverter, isolators, cables or junction boxes, and never touch damaged panels, exposed wiring or connectors.
• Check your panel manufacturer’s installation manual. Most set out approved cleaning methods. Following them helps keep your warranty intact.

If you see cracked glass, scorch marks, loose cables or a damaged rooftop isolator while you’re looking, stop. Don’t touch anything. Call a licensed electrician or your installer.

Should you pay for professional solar panel cleaning?

Professional cleaners use pure (deionised) water, soft brushes and roof safety equipment. Prices vary with roof height, pitch, access and how dirty the panels are. As of 2026, published Australian rates range from about $7.50–$10 per panel (SolarQuotes) to $10–$20 per panel (several cleaning and installer price guides). Many cleaners also have a minimum call-out charge, so small systems cost more per panel.

Panel counts assume modern 440–475 W panels. Prices are market ranges, not Solar Beat prices. Get a fixed quote.

Energy Safe Victoria warns that some operators offering “maintenance” are only cleaning panels. They aren’t trained to identify or fix electrical faults. A clean on its own won’t find a deteriorating DC isolator or a loose connection. The better-value option is usually to ask for cleaning as part of a full system service by a licensed electrician, which checks the wiring, isolators and inverter at the same time.

How often should solar panels be cleaned?

There’s no fixed rule. A practical approach for SA and VIC homes:

• Most homes: no routine cleaning. Rinse from the ground or book a clean only when you can see droppings or your monitoring shows an unexplained drop.
• Dusty, coastal or rural sites: check every 6–12 months, especially after a long dry spell or harvest.
• Flat-mounted or low-tilt panels: clean once or twice a year.
• Bird problems: clean, then fix the cause. Our guide to bird-proofing solar panels explains mesh options.

Separately, plan a full safety service at least every two years. Energy Safe Victoria recommends a service by a licensed A-grade electrician at least once every two years. The Clean Energy Regulator suggests having a licensed electrician check your system is safe every year.

Shade is often a bigger problem than dirt. If a tree has grown into your array’s sunlight, trimming it (using a qualified arborist) will usually do more than any clean. Our guide to roof orientation and shade explains why. If you’re comparing your output with what a new system should make, see how much power a 6.6kW system produces.

Frequently asked questions

Can I use a pressure washer on solar panels?

No. High-pressure water can force its way past the seals between the glass and the aluminium frame and may damage coatings or connectors. Use a garden hose on a gentle spray so water falls like rain, plus a soft brush on an extension pole for stubborn marks. Check your panel manufacturer’s manual for its approved cleaning method.

Can I use detergent or window cleaner on my solar panels?

It’s best not to. Clean water is enough for almost all soiling. Detergents, solvents and abrasive pads can damage anti-reflective coatings, leave residue that attracts dust, may breach the manufacturer’s cleaning conditions and can wash into your rainwater tank. Professionals typically use deionised water and soft brushes.

Does rain clean solar panels?

Mostly, yes. Panels tilted at 10 degrees or more shed most everyday dust when it rains, which is why routine cleaning rarely pays off in Adelaide or Melbourne. Rain won’t reliably remove bird droppings, lichen, sticky pollen or dirt on flat-mounted panels, so those may need a gentle manual clean.

Will cleaning my panels void the warranty?

Not if you follow the manufacturer’s cleaning instructions. Warranties can be affected by damage from pressure washers, abrasive tools, harsh chemicals or walking on panels. Read the cleaning section of your panel’s installation manual, or ask your installer, before you or a contractor clean them.

Not sure whether your system needs a clean, a service or a repair? Our Adelaide and Melbourne team can inspect your panels, wiring and inverter in one visit. Browse our home solar systems, read our Adelaide solar guide, or contact us to book a service.

Sources: energy.gov.au Solar Consumer Guide – Look after your solar system (accessed Oct 2026); Energy Safe Victoria – Campaign urges home solar owners to prioritise safety (22 Sep 2025); Clean Energy Regulator – Rooftop solar (accessed Oct 2026); SolarQuotes – Solar panel cleaning (updated Jun 2025). Cleaning prices are indicative 2026 market ranges and vary by provider and roof access. Featured image: Asurnipal / Wikimedia Commons, CC BY-SA 4.0.