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    San Mateo County · Reported cost

    Solar Panel Cost in San Mateo, CA (2026): $4.78/W Reported

    By Updated 9 sources citedSan Mateo, San Mateo County

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    San Mateo homeowners who bought their own solar systems reported a median of $4.78 per watt between January 2025 and May 2026, across 161 systems. The middle half paid $3.64 to $6.55 per watt.

    A 5.9 kW system, the median size connected in San Mateo in 2025, comes to about $28,200 at that median, or $21,500 to $38,600 across the middle half.

    Those are reported costs, not a quote, and no federal credit comes off a San Mateo system finished in 2026: 26 U.S.C. §25D does not cover one whose installation is completed after December 31, 2025 (state and federal rules).

    Median reported cost
    $4.78/W
    San Mateo addresses, 161 systems
    Middle half
    $3.64 to $6.55/W
    25th to 75th percentile
    Typical 5.9 kW system
    $28,200
    5.9 kW × $4.78/W, before any incentive
    Same system, middle half
    $21,500 to $38,600
    size: San Mateo addresses, 2025 median

    Source: California Distributed Generation Statistics (CPUC), Interconnected Project Sites data set, data through May 31, 2026, checked September 24, 2026. Homeowner-owned, solar-only systems of 1 to 25 kW; leases, PPAs and battery systems are left out (method). The CPUC notes these costs are not verified by the government.

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    California Rate Relief is a referral service. We are not a licensed contractor. California Rate Relief is compensated by a solar provider when a homeowner we refer signs an agreement. How we make money

    What a solar permit costs in San Mateo

    San Mateo's published permit fee for a home rooftop system is $450 (combination permit, solar on a single-family dwelling). A new energy storage system installed on its own is $450.

    That is exactly the $450 limit that Government Code §66015 sets for a home system up to 15 kW.

    • What San Mateo publishes: San Mateo's Adopted Comprehensive Fee Schedule for 2026-2027 charges $450 for each combination permit for a solar energy system on a single-family dwelling, and $450 flat for a new energy storage system installed on its own, and notes that both fees are set by state law. SolarAPP+ charges its own processing fee; the City's page does not state the amount.
    • How to file: Yes. Eligible residential, roof-mounted retrofit systems go through SolarAPP+, and the City permit is then applied for at the City's Online Permit Center.
    • Automated permit platform: SolarAPP+

    Sources: City of San Mateo, SolarApp+ for Solar Installers, checked September 23, 2026; City of San Mateo, Adopted Comprehensive Fee Schedule 2026-2027 (Building: solar energy systems; new energy storage systems), checked September 23, 2026; County of San Mateo, Instant Residential Solar and Energy Storage System Permits (unincorporated addresses only), checked September 23, 2026; Gov. Code §66015, checked September 24, 2026. San Mateo in the California Solar Cost Index sets this fee beside every other city's.

    Solar in San Mateo: installs, leases and batteries

    Home solar systems connected at San Mateo addresses: 282 in 2021, 521 in 2022, 520 in 2023, 230 in 2024 and 274 in 2025. So connections peaked in 2022 and 2025 ran 47% below that peak. Another 160 were connected from January to May 2026.

    Of the 274 systems connected in San Mateo in 2025, 28% were leased or on a PPA, so a solar company owns them, and 72% belonged to the homeowner. 57% had a battery, about as often as the 55% statewide. The median San Mateo system was 5.9 kW, and 74 companies connected at least one.

    San Mateo beside San Mateo County and Statewide, 2025
    San MateoSan Mateo CountyStatewide
    Systems connected in 20252742,230145,404
    Leased or on a PPA28%28%45%
    With a battery57%55%55%
    Median system size5.9 kW6.8 kW6.15 kW
    Median reported cost$4.78/W (161)$5.43/W (1,203)$4.14/W (58,628)
    Companies connecting systems742122,475

    Source: CPUC DG Stats, data through May 31, 2026. Counts are home systems given permission to operate each year; a city means the service city on the application.

    Your utility: PG&E

    San Mateo is billed by Pacific Gas and Electric Company (PG&E). PG&E's average residential rate is 33.7¢/kWh (June 2026 (unchanged since March 2026); rate tracker).

    WestLight Energy (formerly Peninsula Clean Energy) supplies generation for many San Mateo addresses while PG&E delivers and bills; your bill shows which. Source: WestLight Energy (formerly Peninsula Clean Energy): serves San Mateo County and Los Banos; one PG&E bill.

    Before you compare proposals

    The San Mateo project checks that change the decision

    San Mateo's permit fee is a flat figure set by state law, so the parts of a quote that vary are the design, the roof and the electrical work. Make each bid show them.

    Ask the same three questions

    1. Does the design fit SolarAPP+'s eligibility checklist for a roof-mounted retrofit system, or will it need another review?
    2. Is a battery included now or planned for later? A new storage system installed on its own carries its own $450 City permit.
    3. Does the bill model use WestLight Energy's generation charges and PG&E's delivery charges from your own bill?

    Local checks

    The City permit fee is fixed

    San Mateo's 2026-2027 schedule charges $450 per combination permit for solar on a single-family home. If a bid's permit line is much larger, ask what else it covers.

    Unincorporated addresses use the County

    If the home is in unincorporated San Mateo County rather than inside city limits, the County issues the permit through its Symbium instant-permit platform, not the City.

    One PG&E bill, two providers

    WestLight Energy says its customers get one bill from PG&E carrying WestLight's generation charges and PG&E's delivery charges. Check which generation provider your account shows before comparing bids.

    Related decisions

    Local sources and limits

    Before you sign

    In San Mateo the middle half of reported costs spans $3.64 to $6.55 per watt, and roof, panel work, equipment and contract terms explain most of that gap. California Solar Tax and Permit Rules for 2026 covers them, and the tax, lease and disclosure rules a San Mateo contract follows.

    Frequently asked questions

    How much does solar cost in San Mateo?

    About $28,200 for a 5.9 kW system, at the $4.78 per watt median that San Mateo owners reported (161 systems, January 2025 to May 2026; middle half $3.64 to $6.55). Source: CPUC DG Stats. No federal credit applies to a San Mateo system finished in 2026.

    What does a solar permit cost in San Mateo?

    $450 for a home rooftop system on San Mateo's published schedule (checked September 23, 2026); the state limit is $450 up to 15 kW under Gov. Code §66015.

    How much does solar panel installation cost in San Mateo County?

    No public source prices an installation for the county, and the parts that differ from one address to the next are set locally. Each city and town in San Mateo County issues its own solar permits; the City of San Mateo charges $450 per combination permit for solar on a single-family home in its 2026-2027 fee schedule. Homes in unincorporated San Mateo County are permitted by the County, which issues instant residential solar and battery permits through Symbium and accepts only unincorporated addresses there. WestLight Energy is the generation provider for San Mateo County, and PG&E delivers the power and sends one bill with both sets of charges.

    Which utility serves San Mateo?

    Pacific Gas and Electric Company (PG&E). Its average residential rate is 33.7¢/kWh, as of June 2026 (unchanged since March 2026).

    Sources

    The tax, contract and permit rules every California city shares, with their statutes: California Solar Tax and Permit Rules for 2026.

    San Mateo in the California Solar Cost IndexIts permit fee, permit platform and utility beside every other city's.Compare solar companies in San MateoWho installs in San Mateo and what each written proposal should include.

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