Walnut, CA 91789 solar market data
Updated May 6, 2026 By The SolarDNA Data Team
Walnut 91789 has 2,853 solar installations at a median installed cost of $4.18/W, installations up 0.5% over the trailing twelve months, and a Market Score of 49 — higher than 84% of U.S. zip markets.
Versus California
How 91789 compares with the state
Installed cost
$0.08/W below
state median $4.26/W
Market score
49 vs 53
California scores 53
Share of state installs
0.13%
of 2.3M tracked statewide
Battery attach
15.6%
state 12.7%
Statewide momentum
▲ 1.1%
residential solar added in California, 12 months through Jul 2026
Statewide market
2.3M systems
30.9% of homes · utility-reported through Jul 2026
Next-12-month outlook: 182–222 installs (midpoint 202)
Trailing-12-month installs carried forward at half the observed growth rate (capped at ±30%), with a ±10% band. Not a forecast of permits or policy.
Growth & pricing
91789 by year
201 installs in the trailing twelve months vs 200 before
Installations by year
Median installed cost, $/W DC by year
Installer comp set
Who installs in 91789
Ranked by systems recorded in this zip
| # | Installer | Installs | 12-mo | Avg kW | $/W |
|---|---|---|---|---|---|
| 1 | TESLA | 561 | 21 | 12.94 | $5.12 |
| 2 | SUNRUN | 305 | 69 | 7.58 | $3.96 |
| 3 | SUNPOWER | 154 | 9 | 6.89 | $4.48 |
| 4 | LEONARD ROOFING | 85 | 0 | 3.28 | $2.28 |
| 5 | SOLARMAX | 79 | 0 | 8.16 | $3.29 |
| 6 | FREEDOM FOREVER | 65 | 5 | 8.09 | $3.39 |
| 7 | SOLAR VAST | 60 | 0 | 8.9 | $4.05 |
| 8 | VERENGO | 50 | 0 | 5.85 | $4.57 |
| 9 | BURKE ELECTRIC | 48 | 0 | 5.64 | $5.00 |
| 10 | TRUE POWER SOLAR | 38 | 0 | 9.5 | $4.47 |
| 11 | PETERSENDEAN | 37 | 0 | 5.15 | $3.33 |
| 12 | SOLAR OPTIMUM DESIGN ELECTRIC | 37 | 0 | 8.56 | $2.80 |
Neighboring zips
The nearest zip markets
By distance between zip centroids
| Zip | Distance | Installs | $/W | Score |
|---|---|---|---|---|
| 91788 Walnut | 1.0 km | 32 | $3.16 | 44 |
| 91792 West Covina | 4.0 km | 853 | $4.51 | 42 |
| 91765 Diamond Bar | 4.3 km | 2,593 | $4.08 | 61 |
| 91748 Rowland Heights | 5.6 km | 1,783 | $4.35 | 45 |
| 91791 West Covina | 6.6 km | 1,975 | $4.22 | 46 |
| 91744 La Puente | 7.7 km | 2,074 | $4.51 | 39 |
Same city
Other zips in Walnut
Equipment
What gets installed in 91789
Share of systems with a recorded brand
Modules
QCELLS NORTH AMERICA20.2%
SUNPOWER13.7%
KYOCERA SOLAR8.6%
LG ELECTRONICS5.3%
CSI SOLAR5.1%
Inverters
ENPHASE ENERGY33.4%
SOLAREDGE24.7%
ABB10.0%
SUNPOWER8.9%
TESLA5.9%
Frequently asked
Quick answers about 91789
How many solar installations are there in 91789?
SolarDNA counts 2,853 active solar installations in Walnut 91789, 2,809 of them residential, with data through May 6, 2026.
How much does solar cost in 91789?
The median residential system in 91789 cost $4.18 per watt over the trailing twelve months, $0.08/W below the California median.
Is solar growing in 91789?
Installations in 91789 are up 0.5%: 201 in the trailing twelve months versus 200 before.
Who installs solar in 91789?
TESLA, SUNRUN, SUNPOWER lead the 409 installers with systems in 91789. The full comp set is above.
Is 91789 a good market for solar sales?
91789 scores 49 out of 100 (Great, higher than 84% of U.S. zip markets).