How to Clean Solar Panels on Your Roof Without Causing Damage

Solar panels are a significant investment, and like any investment, they need regular maintenance to keep performing at their best. Dirty panels can lose 15–25% of their energy output, costing you money every month they go uncleaned. But cleaning them the wrong way can scratch the glass, void your warranty, or even put you at risk on a sloped roof.

Here's everything you need to know about cleaning solar panels safely and effectively.

Why Solar Panel Cleaning Matters

Utah's environment is tough on solar panels. Dust, pollen, bird droppings, and hard water mineral deposits all accumulate on the surface and block sunlight from reaching the cells. In dry climates like Salt Lake City, rain doesn't wash panels clean the way you might expect — it often leaves behind mineral deposits that build up over time.

A thin layer of grime might not look like much, but it creates a shadow effect across the panel surface that measurably reduces output. Regular cleaning — typically 1–2 times per year — keeps your system generating at full capacity.

What You'll Need

If you're cleaning panels yourself, gather these supplies before you start:

• Soft-bristle brush or squeegee — never use abrasive scrubbers

• Mild, non-abrasive soap (dish soap works; avoid anything with harsh chemicals)

• Soft cloth or microfiber towel

• Garden hose with a gentle spray nozzle — no pressure washers

• Deionized or distilled water (reduces mineral spotting on the glass)

• Extension pole if panels are out of easy reach

• 
  

Step-by-Step: How to Clean Solar Panels Safely

1. Turn Off Your Solar System First

Before touching anything, shut down your solar panel system according to your manufacturer's instructions. This is a safety requirement, not optional. Check your inverter's manual or the system shutdown procedure provided by your installer.

2. Clean in the Morning or on a Cloudy Day

Never clean panels in direct midday sun. The glass gets extremely hot and cold water hitting it can cause thermal shock — cracking the panel. Morning is ideal: panels are cooler, and any water used will evaporate slowly without leaving spots.

3. Rinse Off Loose Debris First

Use your garden hose on a gentle setting to rinse dust and loose debris off the surface. Don't use a pressure washer — the force can damage the panel edges, seals, and underlying wiring.

4. Wash with Soapy Water and a Soft Brush

Apply a mild soap solution with a soft-bristle brush or sponge. Work gently in straight lines — circular scrubbing can leave micro-scratches that accumulate over time. For stubborn bird droppings, let the soapy water soak for a minute before wiping.

5. Rinse Thoroughly

Rinse all soap off completely. Soap residue left on the glass will attract more dirt and can reduce panel efficiency just like grime does.

6. Dry with a Microfiber Cloth (Optional)

If you have hard water, finish with a microfiber cloth or squeegee to prevent mineral spots. This step matters more in Utah's mineral-heavy water areas.

What NOT to Do

• Don't use a pressure washer. Even a low setting can force water under panel edges and damage the seals.

• Don't use abrasive pads or steel wool. These scratch the anti-reflective coating on the glass.

• Don't use harsh chemicals like bleach, ammonia, or vinegar — these can degrade seals and frames over time.

• Don't walk on panels. They're not designed to support foot traffic and can crack under weight.

• Don't lean ladders against the panels. This can crack the frame or shift the mounting hardware.

The Roof Factor: Don't Forget What's Underneath

Cleaning your solar panels is also a good opportunity to check the condition of the roof beneath them. Panels sit directly on your roof and can trap moisture, debris, and heat against the shingles underneath. Issues like cracked or missing shingles under a panel array often go unnoticed until a leak appears inside your home.

If you haven't had a roof inspection recently, it's worth scheduling one alongside your panel cleaning. A roofing professional can check flashing around panel mounts, look for shingle wear beneath the array, and catch small issues before they become expensive ones.

When to Call a Professional

DIY cleaning works fine for ground-mounted or low-slope panels you can safely reach. But for most Utah homes — where panels sit on pitched roofs — professional cleaning is the safer, smarter choice. Here's why:

• Fall risk. Working on a pitched roof with water and soap is a serious hazard without the right equipment and training.

• Warranty protection. Some panel manufacturers require professional cleaning to maintain warranty coverage. Check your documentation.

• Thoroughness. Professionals use deionized water systems and specialized tools that leave panels spotless without streaking or mineral buildup.

• Roof check included. A good roofing and solar cleaning company will inspect the surrounding roof area while they're up there.

According to the U.S. Department of Energy, keeping solar panels clean and well-maintained is one of the most effective ways to protect your investment and maximize energy output over the system's lifetime.

J.B. Reliable Roofing: Solar Panel Cleaning in Utah

J.B. Reliable Roofing offers professional solar panel cleaning for homeowners throughout Salt Lake City and across Utah. With over 24 years of roofing experience and a 5-star Google rating, they're uniquely qualified to clean your panels and check the roof underneath — something a standard cleaning service can't offer.

Their team uses the right tools and techniques to clean without scratching, streaking, or voiding your panel warranty.

Call (385) 424-7736 or book your solar panel cleaning online.

Frequently Asked Questions

How often should I clean my solar panels in Utah? 

Most Utah homeowners should clean their panels 1–2 times per year. If you live in a dusty area or near farmland with heavy pollen, quarterly cleaning may help maintain peak output.

Will rain clean my solar panels? 

Not effectively, especially in Utah. Rain often leaves behind mineral deposits from hard water and doesn't remove bird droppings or thick dust buildup. Manual or professional cleaning is still recommended.

Can I use a pressure washer on solar panels? 

No. Pressure washers can damage the seals, frames, and wiring connections on solar panels. Always use a garden hose on a gentle setting.

Does cleaning solar panels really make a difference? 

Yes. Studies show dirty panels can lose 15–25% of their efficiency. Cleaning them restores full output and can make a noticeable difference in your monthly energy production.

Will cleaning my solar panels void the warranty? 

It depends on the manufacturer. Some require professional cleaning to keep the warranty valid. Check your panel documentation or contact your installer to confirm.

Does J.B. Reliable Roofing also inspect the roof during solar panel cleaning? 

Yes. Because J.B. Reliable Roofing is a full-service roofing company, they can check the condition of your roof and mounting hardware while cleaning — giving you peace of mind that everything underneath the panels is in good shape too.