The answer depends on what is on your panels and what a safe cleaning would cost. A city name or a calendar cannot settle it. Some owners have concentrated deposits that rain leaves behind. Others have light dust that washes off. A cleaning can remove accessible surface material; it cannot repair a failed inverter or reverse permanent shade.
What does the research establish?
Solar soiling studies show that output effects vary with deposit type, panel tilt, weather, and location. A result from a different climate cannot prescribe a visit interval or return on investment for one East Bay roof. The National Renewable Energy Laboratorydescribes the site-specific trade-off between soiling losses and cleaning cost. Use that as a decision framework, not a promised percentage recovery.
What can you check at home?
Look at the array from a safe ground-level position. Note concentrated bird deposits, lower-edge buildup, or a film that remains after rain. Save a dated photo if you can get one without climbing. In your monitoring app, compare clear days in similar seasons and allow for shade, temperature, weather, and inverter alerts. One low reading does not identify dirt as the cause.
If the glass is clear but the app shows a persistent drop or fault, ask the installer to diagnose the system first. A cleaner should not claim that washing will fix an electrical issue. If deposits are visible and monitoring suggests a repeated effect, a cleaning quote can help you decide whether the job is worth the access cost.
When might cleaning be worth it?
A site with recurring bird activity, construction dust, or deposits that survive rain has a stronger reason for an inspection. The value still depends on panel count, access, soiling, and what can be removed safely. Ask what the visit includes and whether a visual record is part of the quoted scope. The published residential range on this site is $175 to $350 for 10 to 40 panels; difficult access, heavy deposits, and larger arrays need a specific quote.
When should you wait or choose another trade?
If a safe inspection finds only light dust and comparable production is stable, wait and inspect again after rain or the next dry period. If a module is cracked, wiring is exposed, or an inverter reports a fault, contact the installer or a qualified electrician before arranging cleaning. The module maker's instructions determine what cleaning method is permitted; a visit cannot guarantee warranty coverage or a measured increase in output.
Send the address, approximate panel count, mount type, visible deposit, and last cleaning date when requesting a quote. Mention safe photos available for follow-up. Total Solar Cleaning can assess a scoped visit and discuss whether a repeat schedule makes sense after observing the site. Use the contact form or call (833) 444-4173. Photographs can be arranged after first contact.