How Often Should You Clean Solar Panels in the Central Valley?

Rooftop solar is everywhere in Fresno, Clovis and across the Central Valley, and for good reason. We get plenty of sun. But we also get plenty of dust, and that dust doesn’t stay in the air. It settles right on top of your panels.

So how often should you clean them? For most Central Valley homes, every six months to a year is a good rule of thumb. If you live near farm fields, orchards, dirt roads or construction, or if birds like to hang out on your roof, you may benefit from cleaning more often, especially through the dry summer and fall. Homes in more sheltered neighborhoods can often stick closer to once a year.

Why solar panels get dirty in the Valley

Solar panels work by capturing sunlight. Anything that sits on the glass and blocks that light can reduce how much power your system produces. In the Valley, a few things cause most of the buildup:

• Ag and field dust: Plowing, harvesting and dry wind kick up fine dust that settles on rooftops for miles around.
• Pollen: Spring pollen leaves a sticky film that holds onto dust.
• Ash during fire season: Wildfire smoke can drop a gray layer of ash on panels, sometimes for weeks at a time.
• Bird droppings: Droppings are one of the worst offenders because they block light in concentrated spots and bake on in the heat.
• Leaves and debris: Trees nearby can drop leaves and twigs that collect along the bottom edge of panels.

Won’t the rain just clean them?

Rain helps a little, but it’s not a reliable cleaner here. The Valley gets very little rain during the long, dry months when dust is at its worst. And when a light rain does fall, it often mixes with the dust and leaves a muddy residue behind as it dries, especially along the lower edge of the panel where water collects.

Morning dew can do the same thing on a smaller scale. It dampens the dust overnight, then the sun dries it into a thin film that’s harder to rinse off than loose dust.

Panels also tend to be installed at fairly low angles on many Valley homes, which means dirt doesn’t slide off as easily as it might on a steeper roof.

Signs your panels need cleaning

You don’t have to guess. Here are a few ways to tell it’s time:

• Your monitoring app shows lower production than usual for similar sunny days, without another obvious explanation.
• You can see a layer of dust, film or spots on the panels from the ground or from a second-story window.
• Bird droppings are visible on the glass.
• It’s been more than six months to a year since the last cleaning, or you just came through a heavy pollen or fire season.
• Pigeons are nesting under the panels, which usually means droppings and debris on top as well.

How to clean solar panels safely

If your panels are on a ground mount or are easy to reach without climbing on the roof, you may be able to rinse them yourself. Before you start, check your panel manufacturer’s or installer’s cleaning guidelines, since some have specific recommendations to protect your warranty. Then keep these basics in mind:

• Clean in the early morning or evening when panels are cool. Spraying cold water on hot glass in the middle of a Valley summer day is not a good idea, and cleaner dries too fast in the heat.
• Use a soft brush or sponge on an extension pole. Never use abrasive pads, scrapers or stiff brushes that could scratch the glass.
• Skip the pressure washer. High pressure can damage panel seals and frames.
• Avoid harsh chemicals and household cleaners that can leave residue or streaks.
• Use clean, soft water if you can. Hard tap water can leave mineral spots as it dries, which defeats the purpose.

For rooftop panels, our honest advice is to stay off the roof. Roofs get slippery once water is involved, tile roofs can crack under foot traffic, and working around electrical equipment at heights adds real risk. Rooftop solar cleaning is a job for a professional crew with the right equipment and safety practices.

What about pigeons under the panels?

Pigeons love the shaded, sheltered space under rooftop solar panels. Once they move in, you’ll usually see droppings on the panels and roof, nesting debris that can wash into gutters, and a lot of noise. Cleaning the panels helps, but if the birds still have a place to nest, the mess comes right back.

That’s why many homeowners pair solar cleaning with bird proofing. At Ducky’s, we can clean your panels, remove nests and debris, and install prevention around the panels so pigeons can’t get underneath, all in the same visit. Our approach focuses on keeping birds out, not harming them.

How we clean solar panels

At Ducky’s, we clean solar panels with soft brushes and purified water. There are no harsh chemicals and no pressure washers, and the purified water dries spot-free so you’re not left with mineral residue. We also take a look for debris collecting under the panels while we’re up there. We clean rooftop and ground-mount systems for homes, and solar arrays on commercial buildings, farms and ag properties across the Valley. Recurring cleaning plans are available if you’d rather not keep track of the schedule yourself.

Many homeowners like to book a solar cleaning in late spring, once pollen season winds down, and again in fall after harvest dust and fire season ash have settled. That timing lines up with when panels tend to look their dirtiest, and it pairs nicely with a fall gutter cleaning.

Need help? Call Ducky’s

If your panels are looking dusty or the birds have moved in, we can help. Ducky’s Exterior Cleaning is licensed and insured, based in Fresno and Clovis, and serves homes and businesses throughout the Central Valley. We’re open 7 days a week from 5am to 10pm, which makes it easy to schedule a cool early-morning cleaning. Call (559) 492-0155 for a free estimate. Every job is backed by our 100% satisfaction guarantee.