Do Solar Panels Need Cleaning in San Diego?
Yes — and the production loss from skipping it is bigger than most San Diego homeowners realize. Here's the data and what to do about it.
Short answer: yes — and in San Diego more than almost anywhere in California, because we have low rainfall, year-round sun, coastal salt, and high bird activity. Here's what actually happens to a San Diego solar system that never gets cleaned.
San Diego's climate is uniquely hard on solar panels
We get under 12 inches of rain in an average year — most of it concentrated in a few weeks. That means 9+ months of dust, pollen, salt, and droppings baking onto hot glass with no natural rinse. Inland and coastal homes are both affected; the type of dirt just changes.
How much production is your dirty array actually losing?
Independent studies and our own before/after monitoring put typical soiling losses in San Diego at 15–25% within a year of install. On a 7kW system at SDG&E's rates, that's $30–$60 in lost generation every month — money that quietly disappears from your savings calculation.
What about rain? Doesn't that clean them?
Rain rinses light dust but bakes on bird droppings, salt, and pollen — the things actually costing you production. A San Diego rainstorm typically makes panels look cleaner without restoring meaningful production.