Short answer
Solar panels are best cleaned with plain water and a soft brush, then rinsed so no residue is left. Only clean panels you can reach safely from the ground, such as ground-mounted arrays or low panels on a garden building, and check the manufacturer's or installer's guidance first. Never climb onto a roof to clean panels, and avoid abrasives, harsh detergents and high pressure.
Check the guidance first
Before you clean solar panels, look at the documents from your installer or the panel manufacturer. They may set out which cleaning methods and products are acceptable, whether anything could affect the warranty, and any safety steps relating to the electrical system. If you cannot find any guidance, contact your installer.
Look at the panels from the ground too. Cracked glass, damaged frames, loose cables or scorch marks are a job for your installer, not something to clean around.
Roof panels: keep your feet on the ground
Most domestic solar panels are on roofs, and the safe advice is simple: do not climb onto the roof, do not stand or kneel on panels, and do not lean ladders against them. Panels are not designed to take a person's weight, roofs are a serious fall risk, and water and slippery glass make it worse.
Some people use an extendable soft brush from the ground on low panels, for example on a single-storey extension. If you can reach the panels comfortably that way, without overreaching or climbing, the method below applies. If not, leave them to someone with the right equipment.
What you will need
A soft brush, ideally on an extendable pole, a hose with a gentle spray, and clean water. Many people prefer softened or purified water where tap water is hard, because the minerals in hard water can dry as spots on the glass. If you use any cleaning product at all, it should be one your manufacturer allows, used sparingly and rinsed off completely.
Avoid scourers, abrasive cloths, stiff brushes, solvents, strong detergents and pressure washers. These can scratch the glass, damage anti-reflective coatings and push water into seals and connections.
How to clean ground-level solar panels
- Choose a cool time of day, such as early morning or evening, or an overcast day, so water does not dry instantly on warm glass and leave marks. Manufacturers commonly advise against splashing cold water onto hot panels.
- Look over the panels for damage before starting, and stop if you find any.
- Rinse the panels gently with the hose to remove loose dust and soften dried-on dirt.
- Brush gently with the soft brush, working from the top of each panel downwards.
- Soak bird droppings and stubborn marks with water and let them soften before brushing, rather than scrubbing hard.
- Rinse thoroughly with clean water so no dirt or product is left to dry on the glass.
- Let the panels dry naturally.
Things to avoid
Do not use a pressure washer, which can damage seals and force water where it should not go. Do not use household glass cleaners or washing-up liquid in quantity, which can leave a film that attracts dirt. Do not scrape at lichen or droppings with anything hard. And do not clean panels while you or anyone else is up on a roof.
Do your panels need cleaning at all?
Rain clears some dirt, but not all of it, especially bird droppings, lichen and grime on panels with a low pitch. Our guide to whether solar panels need cleaning explains how to check yours using your monitoring and a look from the ground.
When to call a professional
Call a professional for any roof-mounted panels you cannot reach safely from the ground, for large arrays, or where bird droppings and lichen have built up. Problems with the panels themselves, the wiring or birds nesting underneath are for your installer or a specialist rather than a cleaner.
We clean domestic and commercial solar panels using pure water and soft brushes that leave no residue. Pure water dries without spots, so panels are left clean without detergents that could leave a film. Tell us where the array is positioned when you get in touch, as access affects how the work is planned.
Rather have it done for you?
Pure-water cleaning to keep panels clear of dirt and droppings. Family-run by Jason and Lucas Prior, covering south Essex.
Frequently asked questions
What is the best way to clean solar panels?
Plain or purified water and a soft brush, followed by a thorough rinse. Avoid abrasives, harsh detergents and high pressure, and check your manufacturer's guidance first.
Can I use washing-up liquid on solar panels?
It is best avoided, or used only in very small amounts if your manufacturer allows it, because detergent can leave a film on the glass that attracts dirt. Rinse thoroughly if you use any.
Is it safe to clean solar panels on my roof myself?
Not if it means climbing onto the roof or leaning a ladder on the panels. Only clean panels you can reach safely from the ground, and leave the rest to a professional.
Related guides
- Do solar panels need cleaning?: whether your panels need cleaning, what dirties them and how to check without going on the roof.
- What affects the cost of solar panel cleaning: how the number of panels, roof height, pitch, access, droppings, lichen and regular visits change a solar panel cleaning quote.