Is it worth paying to have solar panels cleaned?
For most San Diego homes, yes, but only once or twice a year. A dirty array loses 5 to 15 percent output, and cleaning a 20 panel system costs $150 to $300. On a system producing $1,800 of power a year, recovering 10 percent pays back the cleaning in under three months.
Last updated: July 2026
We get asked this more than any other question, usually by someone who just got a quote and is doing the math in their head. Fair question. So here is the honest version, including when the answer is no.
The numbers we actually see
We meter output on jobs where the homeowner has a monitoring app and is willing to check. A soiled array in La Jolla that had not been touched in two years came back 11 percent after cleaning. An inland system in Scripps Ranch, dusty but no bird activity, came back 6 percent.
The outliers are bird droppings. A single dropping sitting on a cell can knock out the whole string through that bypass diode, and we have measured 18 percent losses on arrays that were otherwise clean but had four or five hits near the roof peak.
Rain does not fix it. San Diego averages under 11 inches a year and most of it falls in three months. Between April and November your panels get essentially nothing, and light rain actually makes it worse by leaving a dust-slurry ring when it dries.
What it costs and what it returns
| System size | Cleaning cost | Typical annual production value | Value of 10% recovery |
|---|---|---|---|
| 12 panels (~4 kW) | $120 to $180 | $1,100 to $1,400 | $110 to $140 |
| 20 panels (~7 kW) | $150 to $300 | $1,700 to $2,100 | $170 to $210 |
| 32 panels (~11 kW) | $250 to $450 | $2,700 to $3,300 | $270 to $330 |
Read that table honestly. One cleaning a year roughly breaks even to slightly ahead on a small system, and comes out clearly ahead on a large one. Two cleanings a year only make sense coastal, or under trees, or with birds.
When we tell people not to bother
Inland, no trees, no birds, array cleaned within the last eight months. We have driven out to Poway, looked at a roof, and told the homeowner to call us in the spring. There was nothing on it worth $200.
Ground-mount systems that get hosed down by the sprinklers also tend to stay reasonably clean, though hard water spotting becomes its own problem and that one does need a deionized rinse.
And if your system is under a production guarantee that the installer services, check that first. Some of them include an annual clean.
Coastal arrays are the real case
Salt film is the difference. In Point Loma, Del Mar, Solana Beach, and Coronado we see a haze that does not look like much from the ground but cuts transmission measurably. It is hygroscopic, meaning it pulls moisture and grabs dust that would otherwise blow off.
Those homes we recommend twice a year, roughly March and September. Our post on coastal versus inland cleaning frequency goes deeper on why.
How we clean them
Deionized water through a soft brush on a water-fed pole. No detergent, no pressure. Deionized means zero total dissolved solids, so the panels dry with no spotting and we never have to squeegee glass at 20 feet.
Never a pressure washer. Panel seals are rated for rain, not for 2000 PSI, and forcing water past a frame gasket is how you turn a $200 cleaning into a $900 microinverter replacement.
We work early, before the glass heats up. Cold water on a 140 degree panel is a thermal shock risk on older mono-crystalline modules and we have seen one crack from it, which was enough.
What a typical job looks like
A 24 panel array in North Park last month: 50 minutes, two of us, $190. Roof pitch was 4:12 so we worked from the ladder and the pole, never stepped on the modules. Output was up 8 percent on the app three days later, which the homeowner texted us because we asked.
Access drives the price more than panel count. A 5:12 or steeper roof, or a second story with no ladder setback, adds $50 to $100.
If you want the frequency question answered rather than the worth-it question, we covered that in how often to clean solar panels in San Diego, and our solar panel cleaning page has the service details and the areas we cover.
Cleaned your array recently? Mentioning your neighborhood and the panel count in a Google review helps other San Diego owners figure out what to expect.