September 20, 2026
Two things: deionized water and a soft bristle brush.
That is the whole list. It is the method solar panel manufacturers have tested and recommend for their own product, and everything else about a professional cleaning comes down to doing those two things well.
Deionized water does the pulling
Deionized water has had its minerals stripped out. Because it is carrying nothing, it actively pulls contaminants off the glass rather than just wetting them.
It also dries clean. There are no minerals left behind to spot the panel, so there is no film for the next round of dust to stick to.
A soft bristle brush handles the harsh layers
Water alone will not lift everything. Panels in the Central Valley build up in layers, and the oldest layers are baked on.
The soft bristle brush agitates those harsher layers loose while the water carries them away. Soft is the important word. The bristles are firm enough to move buildup and gentle enough that they never mark the glass.
Together they leave the panels looking the way they did on installation day.
What should not go on your panels
Soap and additives
If a company uses soap or any additive, treat it as a quick sign that they are not set up with the right equipment to do the job the way manufacturers recommend. Steer away from them.
Soap is what you reach for when your water cannot do the work. Deionized water does not need the help, and soap leaves a residue that brings the dust back faster.
Hose water
If you have harder water at home, do not just rinse your panels with the hose. It feels harmless and it is not.
Every rinse leaves minerals and contaminants behind on the glass. Over time they stain it. Removing that staining properly takes chemicals, and those chemicals are the kind that can void your solar panel warranty. You end up with one problem stacked on another.
Pressure washers and abrasive pads
Both are on manufacturer do-not-use lists. Scratched glass cannot be repaired.
Hydro powered brushes, and why we finish in half the time
At Golden Rays we clean with hydro powered solar cleaning brushes. The water that cleans the panel also drives the brush head, so the brush does the scrubbing and the technician guides it.
That makes the clean faster and safer for our technicians, and it is how we get a service done in about half the time of companies working by hand. A single-story home with 55 panels takes our crew around 30 minutes.
Less time on your roof is better for your roof, better for the crew, and part of why our pricing comes in under the market.
How we clean in 100 degree heat
Summer is when the Valley goes over 100 degrees, and it is also when demand for solar cleaning is at its highest. We keep working through it because the operation is built for it.
- Speed limits rooftop time. Finishing in half the time means our technicians spend half as long exposed to the heat.
- We heat the deionized water. On hot days cold water on hot glass is a real imbalance, and that temperature gap carries a risk of cracking the panel. Heating the water closes the gap.
- We look after the crew. Cooling gear on the roof, plus unlimited iced water, ice, electrolyte packets and snacks on every truck, so every technician stays safe.
Three questions to ask any cleaning company
- What water do you use? The answer should be deionized.
- Do you use any soap or additives? The answer should be no.
- What touches the glass? The answer should be a soft bristle brush and nothing else.
Book a cleaning done the right way
See our solar panel cleaning service for how a visit works, or get a price in seconds from the cost calculator.
Not sure your panels need it yet? Read what happens if you don’t clean your solar panels, including when we would tell you to wait.