Cleaning · Guide
How to clean solar panels safely
Most solar panels in the UK don’t need cleaning often. The Energy Saving Trust says rain will clean panels tilted at 15 degrees or more. Bird droppings, moss and grime on shallow roofs are different: they don’t wash off, and they can cut your output.
Mon–Fri 9:00am–5:00pm · Clear written quote before any work starts
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Call 0800 156 0191, Monday to Friday, 9:00am–5:00pm, or send us a message through our contact page.
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Check first
Do your panels need cleaning?
If you clean them yourself, do it from the ground. Never climb onto the roof or stand on the panels.
Look from the ground (binoculars help) for:
- bird droppings that the rain hasn’t shifted;
- moss or lichen along the bottom edge of the frames;
- a film of dirt, especially on a shallow or flat roof;
- leaves or debris along the bottom edge;
- salt residue if you live near the coast.
Also compare your generation with the same month last year. If the panels look clear and the output is normal, leave them alone. Cleaning panels that don’t need it adds risk for no gain.
Kit
What you need.
- A telescopic water-fed pole with a soft brush head, used from the ground. The Health and Safety Executive’s advice is to avoid working at height where you reasonably can, for example by using a water-fed pole.
- Purified or low-mineral water. It dries without leaving spots. Panel manufacturers’ cleaning instructions commonly recommend low-mineral water, and hard tap water can leave marks that hold dirt.
- A soft brush or sponge. Nothing abrasive.
That’s all. Most panels need no detergent. A few manufacturers allow a small amount of mild, biodegradable washing-up liquid, but check your panels’ own cleaning instructions first and rinse thoroughly.
Step by step
Step by step.
- Pick a cool time: early morning, evening or an overcast day. Cold water on hot glass risks thermal shock, and water dries more slowly, so there are fewer marks.
- Look before you clean. If a panel is cracked, a cable is loose or damaged, or you see scorch marks, stop. Don’t wet damaged panels or cabling; call an engineer. See cracked or faulty solar panel?
- Soak first. Wet the panels to loosen dirt and let bird droppings soften rather than scrubbing at them.
- Brush gently from the top down with the soft brush.
- Rinse with purified water and let the panels dry naturally.
- Check your generation over the next few bright days.
Avoid
What never to use.
- Pressure washers. High-pressure water can be forced past the seals into junction boxes and connectors. Manufacturers’ cleaning instructions rule out high-pressure cleaning.
- Harsh chemicals, solvents, bleach or household glass cleaners. They can damage the coating on the glass or the seals, or leave a film that attracts more dirt.
- Abrasive pads or scourers. They scratch the glass.
- Rotating brushes. At least one major manufacturer warns they can cause micro-cracks.
- Ladders against the panels or gutters, or standing and kneeling on panels. You can crack the cells even when the glass looks undamaged.
Safety
Staying safe.
- Don’t work at height. Use a pole from the ground or leave the job to a professional. The HSE says a ladder shouldn’t be your automatic choice, and is only suitable for low-risk, short tasks.
- Check for overhead power lines before you raise a long pole.
- Remember the panels are live in daylight. Solar panels produce electricity whenever there’s daylight. Don’t touch the cables, connectors or junction boxes, and don’t clean panels that are damaged.
How often
How often should solar panels be cleaned?
On most pitched roofs, a clean every year or two is plenty, and some panels rarely need it. Clean more often if:
- the roof is shallow or flat (see solar panels on a flat roof), or the panels are ground-mounted;
- you live near fields, a busy road, a building site or the coast;
- trees drop leaves, sap or blossom onto the array;
- birds perch on the ridge or nest under the panels.
Pigeons under the panels are a separate problem: cleaning won’t stop them coming back. See solar panel bird proofing.
Getting help
When to call in a professional.
- You can’t reach the panels safely from the ground.
- Moss or lichen has taken hold, or bird mess keeps coming back.
- Anything looks damaged, or output is still low after cleaning. See solar panels not working?
We clean with purified water and soft brushes, and every clean includes a system check, across England, Wales and southern Scotland. You get a clear written quote before any work starts. See solar panel cleaning and solar panel maintenance.
Sources: Energy Saving Trust, Solar panels (updated August 2026); HSE, Working at height whilst window cleaning; panel manufacturers’ cleaning instructions.
Rather not get the ladder out? Our Solar Maintenance Plans include a professional panel clean and full system service every year, and you book each visit from your My Solar account. See what a maintenance plan costs.
Questions
The things people ask before they ring.
Not answered here? Call 0800 156 0191, Monday to Friday, 9:00am–5:00pm.
What is the best way to clean solar panels?
From the ground, with a water-fed pole, a soft brush and purified water, on a cool morning or evening. Soak the dirt first, brush gently from the top down, rinse and let it dry. No pressure washers, harsh chemicals or abrasive pads, and never go on the roof.
Can I clean solar panels with tap water?
In soft-water areas, usually yes. Hard water can leave mineral spots that hold dirt, which is why purified or low-mineral water is better. Many manufacturers recommend low-mineral water in their cleaning instructions.
Can I use washing-up liquid on solar panels?
It’s rarely needed. A few manufacturers allow a small amount of mild, biodegradable washing-up liquid, but check your panels’ cleaning instructions first, rinse thoroughly, and never use harsh chemicals or household glass cleaners.
Is it safe to clean solar panels myself?
Only from the ground, with a water-fed pole, and only on undamaged panels. Don’t climb onto the roof, work from a ladder or stand on the panels. If you can’t reach them safely from the ground, use a professional.
Ready when you are
Rather leave it to us?
We’ll call you back to talk it through, and you get a clear written quote before any work starts. Mon–Fri 9:00am–5:00pm.