Does Rain Clean Solar Panels? The Truth Nobody Tells Homeowners
Introduction
Here's the biggest myth in the solar industry:
"Don't worry, the rain will clean your solar panels."
Wrong.
Misleading.
A lie that costs homeowners thousands per year in lost efficiency.
Today we'll break down the truth behind rain and solar cleanliness — specifically for Inland Empire homeowners.
Does Rain Actually Clean Solar Panels?
Short answer:
No — rain does NOT clean solar panels.
Long answer:
Rainwater:
- Contains dirt
- Contains pollutants
- Leaves spots when it dries
- Doesn't remove baked-on dust
- Doesn't remove bird droppings
- Doesn't remove pollen
- Doesn't remove ash
You wouldn't wash your car by waiting for rain.
Same logic applies to solar panels.
Why Rain Makes Solar Panels Dirtier
1. Hard water residue
When raindrops dry, they leave behind mineral stains.
These stains block sunlight MUCH more than dust.
2. Mud streaks
Dust + water = mud.
When rain dries, it leaves long muddy streaks.
3. Sticky minerals
Rain carries pollutants from the sky → sticky grime on glass.
4. Bird droppings get WORSE
Rain splashes bird droppings across the panel surface.
Real Data Shows Rain Isn't Enough
Studies show that panels lose:
7% after a single month without cleaning
18–25% during spring/summer without cleaning
Up to 40% after wildfire ash buildup
Rain never removes ash or sticky debris — only purified water + brush does.
Why the Inland Empire Has It Worse
Rainfall here is minimal. When it does rain, it's:
- Dirty
- Short
- Light
- Followed by wind and dust
- Followed by humidity that creates stains
This combination leaves panels dirtier than before.
Conclusion
Rain is not a substitute for proper cleaning.
In fact, it often does the opposite — it leaves residue that hurts your solar production.
Get professional solar panel cleaning in Corona and Temecula to remove hard water stains and restore efficiency.
Call to Action
Don't rely on rain.
Rely on professionals.
👉 Schedule a cleaning with FlowState Solar Cleaning today and boost your efficiency immediately.