How Often Should Solar Panels Be Cleaned in California?

California rarely gets enough rain to keep solar panels clean. Here's the right cleaning cadence for South Bay homes, by neighborhood and exposure.

California's long dry season is great for solar production — and terrible for keeping panels clean. With little summer rain, dust, pollen, marine-layer film and bird droppings sit on the glass and block sunlight.

The general rule for California solar panels

Most residential systems should be cleaned every 6–12 months. Commercial arrays, ground-mounts and properties near trees or freeways often need quarterly service.

Coastal South Bay (Redondo, Manhattan, Hermosa, El Segundo)

Marine-layer film and salt deposits build fast. Every 6 months is a safe target — sooner if you see visible film on the glass.

Inland South Bay (Hawthorne, Torrance, Lawndale, Gardena, Inglewood)

Freeway dust and pollen are the main culprits. Annual cleaning is the minimum; twice a year keeps output near peak.

Heavy-exposure properties

Homes under trees, near construction, or in heavy bird-traffic zones can lose 20%+ of output in a single season. Quarterly cleaning is worth it.

Signs it's overdue

Visible dust film, white bird droppings, pollen build-up at panel edges, or a sudden monthly production drop on your monitoring app — any of these means it's time.