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

Installers who connected the most home solar systems in Ontario 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 Ontario by the numbers

SCE approved 1,204 home solar systems in Ontario in 2025, from 94 installers; the top three were named on 52% of them. The busiest year since 2021 was 2023, with 2,054 (2025: -41%). Another 621 were approved from January through May 2026.

2025 mix: 43% leased or on a power purchase agreement, 57% owned by the household; 50% with a battery; median size 3.69 kW DC. San Bernardino County: 58% leased or PPA, 75% with a battery, median 6.3 kW.

Hiring a solar company in Ontario

Solar companies in Ontario apply through the City's Symbium portal, which gives instant plan review for roof-mounted solar and storage systems under 38.4 kW at addresses inside city limits. The Ontario Fire Department requires three-foot roof pathways and its own plan review when panels cover more than half the roof. SCE supplies and delivers the power. Compare at least three written bids built on your own SCE bill.

Start with your Ontario electricity bill

Ontario is Southern California Edison territory for both generation and delivery: the California Energy Commission's map shows no community choice provider over the city. A new system goes on SCE's Solar Billing Plan, so each proposal should use SCE's hourly export credits and your own SCE usage.

The Ontario Fire Department's solar standard

Ontario's fire standard for solar photovoltaic systems, based on the 2022 California Fire Code, applies to systems on homes and businesses, with or without batteries. It exists to keep roof access, pathways to specific areas of the roof, smoke ventilation and emergency egress open for firefighters, and it requires markings on conduit and junction boxes so crews know not to cut them.

For homes, a hip roof needs one three-foot clear pathway from eave to ridge on each slope that carries panels, and a single-ridge roof needs two. Panels stay at least three feet below the ridge, unless the Fire Department approves a method that allows two, and at least 18 inches from a hip or valley that has panels on both sides. When a system would cover more than 50% of a home's roof area, the Fire Department reviews the plans. The Department can grant exceptions, for example where there is access from an adjoining roof or ground-level access.

Symbium permits and SCE billing

The City routes roof-mounted residential solar and energy storage systems under 38.4 kW, and detached single-family reroofs, through Symbium, which gives instant solar plan review once the address is verified to be inside city limits. The City's last report to the Energy Commission, for 2023, showed 661 residential solar permits with 25, about 4%, issued online. Ask each bidder which route your design will use.

On the utility side, a new system goes on SCE's Solar Billing Plan. SCE locks export credit values for nine years from the year you start, gives customers who enroll before 2028 a bonus of about $0.04 per kWh, or about $0.09 if income-qualified, and sends one settlement bill a year in the month the system started service. The Base Services Charge is not reduced by solar credits.

What an Ontario quote needs to explain

A comparison to ask for

Two Ontario bids can differ on roof coverage. Ask each bidder what share of your roof the array covers, since more than 50% triggers a Fire Department plan review, and how its layout keeps the required pathways from eave to ridge. Then compare the price and the remaining SCE bill on the same usage.

Verify the company behind the Ontario quote

Match the business name and license number on each Ontario 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 Ontario solar cost and permit page.

Ontario solar quote questions