Solar Companies in San Marcos, CA: Who Installed the Most Systems in 2025

Installers who connected the most home solar systems in San Marcos in 2025

Counts from utility records, not a ranking or endorsement. Check each license's status and complaint history on the CSLB's Check a License page (checked Sept. 24, 2026).

Source: California Distributed Generation Statistics (CPUC), Interconnected Project Sites data set, data through May 31, 2026 (checked Sept. 24, 2026).

Home solar in San Marcos by the numbers

SDG&E approved 439 home solar systems in San Marcos in 2025, from 76 installers; the top three were named on 49% of them. The busiest year since 2021 was 2023, with 1,664 (2025: -74%). Another 243 were approved from January through May 2026.

2025 mix: 34% leased or on a power purchase agreement, 66% owned by the household; 0% with a battery; median size 5.4 kW DC. San Diego County: 36% leased or PPA, 0% with a battery, median 5.36 kW.

Hiring a solar company in San Marcos

San Marcos gives solar two permit routes: contractors use SolarAPP+ plus a City business license and a Permit Declaration Form, and homeowners with a roof-mounted system of 10 kW or less can apply online on an expedited path the City estimates at one to three business days. Clean Energy Alliance supplies San Marcos generation and SDG&E delivers it. Get at least three written bids that name the route and model your own bill.

Start with your San Marcos electricity bill

San Marcos joined Clean Energy Alliance in April 2023, together with Escondido, and the Energy Commission's map places nearly the whole city inside CEA's area. On most San Marcos bills CEA supplies the generation and SDG&E delivers the power, adds its fixed Base Services Charge and sends the statement. Ask every bidder to start from that bill, not a generic SDG&E rate.

The contractor route and the homeowner route

The City of San Marcos lays out six steps for contractors: confirm the project is eligible, submit the design to SolarAPP+, pay SolarAPP+'s processing fee, obtain a City of San Marcos business license, log into the City's permitting system to submit the forms and pay the permit fees with the Permit Declaration Form attached, and schedule the inspection. The City is explicit that the inspection cannot be booked without a completed Permit Declaration Form.

Homeowners doing their own project have a separate path. A roof-mounted system that produces 10 kW or less can be submitted through the City's online portal under the Roof Mounted Solar PV Expedited option, with an estimated one to three business days of processing. The City also publishes an eligibility checklist, standard plans for string or central inverters and for microinverters, and a reroofing certification. Either way, panels cannot exceed the height limit set by the property's zoning.

What Clean Energy Alliance means for a San Marcos solar home

Clean Energy Alliance began serving San Marcos in April 2023. A home that already had solar kept its net energy metering version when it moved to CEA; a new system first enrolls in SDG&E's program and is then placed in CEA's solar program automatically. CEA calculates charges and credits monthly and closes each account's year on the anniversary of its net metering enrollment.

At that annual true-up, CEA zeroes out leftover credits, and a net energy metering account that produced more than it used is paid $0.06 per kWh of surplus, by check at $100 or more and otherwise as a credit toward the next year. The fixed SDG&E Base Services Charge stays on the delivery side whether or not you have solar. Ask each bidder how much of the system's output its model sends to the grid, and at what value.

What a San Marcos quote needs to explain

A comparison to ask for

Before you compare two San Marcos bids on price, ask each one which route it is using. A contractor bid should name its SolarAPP+ application, its City business license and who signs the Permit Declaration Form. If you are thinking of doing part of the work yourself, the homeowner route is limited to roof-mounted systems of 10 kW or less.

Verify the company behind the San Marcos quote

Match the business name and license number on each San Marcos proposal to the CSLB record, then use our contractor verification steps, the quote comparison guide and the PPA, loan, lease and cash comparison.

Permit fees and the filing route are on the San Marcos solar cost and permit page.

San Marcos solar quote questions