Integrity Pro Washers Team
Professional pressure washing and soft washing specialists serving San Diego County.
Last updated: 2026-06-19
How bad are bird droppings for solar panels in San Diego?
Bird droppings are worse than dust for San Diego solar panels because they sit thick and opaque, fully blocking the cells underneath. A single dropping can create a hot spot that drops a panel's output and, over months, damages the bypass diode. We see 8 to 15 percent array losses from heavy fouling.
Last updated: June 2026
Dust you can argue about. Bird droppings you cannot.
We clean arrays from Point Loma out to Scripps Ranch, and the worst fouling we see is on homes near canyons and eucalyptus stands where crows and pigeons roost. The Soledad and Tecolote canyon edges are the usual suspects.
Why a dropping does more damage than a layer of dust
Dust spreads thin and lets some light through. A dropping is opaque and three-dimensional. It blocks one cell completely.
Here is the part most owners miss. A solar panel is a chain of cells wired in series. Shade one cell hard enough and it stops being a producer and starts acting like a resistor, turning current into heat. That is a hot spot. We have measured surface temperatures over 175 degrees Fahrenheit on a fouled cell with an infrared gun while the rest of the panel sat near 120.
Run that for a few months and the bypass diode that protects the string can fail. Now you have lost a third of the panel, not one cell.
How often should you clean panels in a bird-heavy spot?
For a clean inland roof with no trees, twice a year is plenty. For a Point Loma home under a flight path of gulls, or a Kensington lot backed against a canyon, we recommend every quarter.
| Site condition | Cleaning frequency |
|---|---|
| Open roof, no trees | Twice a year |
| Near trees or canyon | Every 3 months |
| Heavy roosting nearby | Every 6 to 8 weeks |
How we clean it without scratching the glass
We never use a pressure washer on panels. The seals around the frame are not built for it, and forcing water past them is how you fog a panel from the inside.
Our crew uses deionized water and a soft carbon-fiber brush on a water-fed pole. Deionized water leaves no mineral spots, so the glass dries clear without a chamois. For dried droppings we soak first, wait, then brush. Scraping dry waste across tempered glass leaves fine scratches that scatter light for the life of the panel.
A typical 18-panel residential array runs $180 to $320 depending on roof pitch and access. Steep tile roofs in places like Rancho Bernardo cost more because we rig fall protection.
If your production has dipped this spring, see our solar panel cleaning page or the output-loss field test we ran last year. And if we cleaned your array in your neighborhood, a Google review that names the area helps other homeowners find us.