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Solar panel cleaning and maintenance: when, how, and when to call someone

Guides · Homerise team · Reviewed by Joern Haake · Published 5 November 2026 · Rebate figures verified 22 October 2026 · How we write guides

The short answer

Most panels on a pitched roof are rinsed well enough by rain; clean them when you can see a film of dust, salt, pollen or bird droppings, or when your app shows output falling on sunny days. Stay on the ground: a soft long-handled brush and a light spray of water, never a pressure washer. Separately, have the whole system serviced by a licensed electrician at least every two years, as Solar Victoria advises. On a typical 6.6 kW system, losing 5% of output is about 456 kWh a year (an example, as of 22 October 2026).

Do solar panels need cleaning?

Often less than people think. Panels are tilted glass, and rain washes most of the dust off a pitched roof. They're worth cleaning when dirt builds up faster than rain clears it:

a dry spell, a dusty road, building work or farmland nearby;
salt spray close to the sea;
bird droppings, which sit in one spot and shade a panel;
leaves, pollen or lichen under overhanging trees;
panels laid almost flat, where water pools and leaves a ring of grime at the bottom edge.

The best test is your own system's data. Most inverters have an app: compare a clear day this month with a clear day from the same month last year. A steady drop on sunny days, or one string producing less than the others, points to dirt, shading or a fault.

What is dirt worth on a 6.6 kW system?

Published estimates of what dust costs vary too widely to quote one, so here's the arithmetic for an example. A 6.6 kW system in Sydney, Brisbane, Perth or Adelaide makes about 9,121 kWh a year (the regulator's zone rating). If dirt took 5% of that, you'd lose about 456 kWh: worth about $18 a year if it would have been exported at the 4c NSW reference feed-in rate, and up to about $151 if it would have replaced power bought at 33.1c (rules as of 22 October 2026). Weigh that against the cost and the risk of getting it cleaned.

How do you clean solar panels safely?

Keep your feet on the ground. Use a long-handled, soft-bristled brush or broom for what you can reach, and only a light spray from the garden hose. Don't climb onto the roof: falls from roofs and ladders are a leading cause of serious injury, and Safe Work Australia treats even minor roof jobs such as gutter cleaning as carrying the same fall risk.
Water is usually enough. No harsh soap, solvents or abrasive pads; they can damage the glass coating and the seals.
No pressure washer or steam cleaner. A pressure hose can damage panels, and makers' manuals limit the water pressure they allow.
Pick a cool time. Early morning or evening, not the middle of a hot day: cold water on hot glass is something makers' manuals warn against. Don't clean in strong wind or heavy rain.
Never walk on or lean anything on the panels. It can crack the cells without any visible mark on the glass.

Can cleaning void the panel warranty?

It can. Panel warranties expect the panels to be looked after the way the maker's manual describes, and the wrong method (a pressure washer, chemicals, someone standing on them) can give a maker grounds to refuse a claim. Before you hire a cleaning service, check your warranty and ask the cleaner how they work. Solar Victoria also warns about unlicensed workers offering solar cleaning or maintenance.

What does a solar service include, and how often?

Cleaning the glass is not a service. Solar Victoria advises a service by a licensed electrician at least every two years, ideally one accredited for solar, and a check of your warranty: some require the original installer to do it. A service usually covers:

electrical testing of the panels, wiring, inverter and switches;
a visual check for cracked, chipped or discoloured panels and loose mounts;
the DC isolators: Solar Victoria reports that moisture getting into DC isolators was a major cause of solar fires in Energy Safe Victoria's audits;
clearing leaves and debris from under the panels and around the inverter;
the inverter's heatsink and vents, and any error codes it has logged.

Between services, keep the inverter free of dust, spider webs and vermin, and tell your installer about any warning light or code. Some electricity networks also ask for a yearly shutdown test; your installer can show you how.

Should you clean the panels or get them serviced first?

If output has dropped and the panels look clean, book a service before paying for cleaning: shading from a growing tree, a failed string or an inverter fault won't wash off. If the panels are visibly dirty and the system is otherwise healthy, a gentle clean from the ground is the cheapest fix.

Adding a battery to the solar you have?

A service visit is a good moment to ask whether your switchboard, inverter and roof suit a battery. What fits and how it connects: adding a battery to existing solar. If your system is old enough that you're weighing an upgrade, the step-by-step is in solar installation, from quote to switch-on.

Questions people ask

How often should solar panels be cleaned?

There's no fixed schedule. On a pitched roof rain does most of it; clean when you can see dirt, salt or droppings, or when output drops on sunny days. Dusty, coastal and flat installations need it more often.

Can I clean my solar panels with a hose?

Yes, with a light spray from the ground and a soft long-handled brush. Don't use a pressure washer, steam cleaner, harsh soap or abrasive pads, and don't climb onto the roof.

How often should solar panels be serviced?

Solar Victoria advises a service by a licensed electrician at least every two years: electrical testing, a visual check of the panels and mounts, the DC isolators and the inverter.

Does cleaning solar panels increase output?

Only if they were dirty enough to block light. As an example, losing 5% of a 6.6 kW system's output is about 456 kWh a year in Sydney, Brisbane, Perth or Adelaide. Compare clear-day output in your app before and after.

Will a cleaning service void my warranty?

It can if they use methods the panel maker's manual rules out, such as pressure washing, chemicals or standing on the panels. Check your warranty and ask how they clean before you book.

Sources

General information, not financial advice. Rebate rules change: figures on this page come from our rules table, last verified 22 October 2026. How we're paid: installers pay Homerise for introducing you. No brand or installer pays to be mentioned in a guide.