Solar Panel Cost in Napa, CA (2026): $4.05/W Reported

Napa homeowners who bought their own solar systems reported a median of $4.05 per watt between January 2025 and May 2026, across 262 systems. The middle half paid $2.71 to $5.77 per watt.

A 6.32 kW system, the median size connected in Napa in 2025, comes to about $25,600 at that median, or $17,100 to $36,500 across the middle half.

Those are reported costs, not a quote, and no federal credit comes off a Napa 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: $4.05/W; Napa addresses, 262 systems
Middle half: $2.71 to $5.77/W; 25th to 75th percentile
Typical 6.32 kW system: $25,600; 6.32 kW × $4.05/W, before any incentive
Same system, middle half: $17,100 to $36,500; size: Napa 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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What a solar permit costs in Napa

Napa's published permit fee for a home rooftop system is $472 (residential solar PV permit and inspection (10 kW basis)). Fire Prevention plan check review adds $85; the schedule notes a $500 maximum fee.

That is $22 over the $450 limit that Government Code §66015 sets for a home system up to 15 kW. A city may charge more only if it adopts a written finding, in a resolution or ordinance, with substantial evidence of its reasonable cost. Ask Napa for that finding if a quote passes the fee through.

What Napa publishes: Napa's Master Fee Schedule, effective July 1, 2025, lists a residential solar photovoltaic permit and inspection at $472, based on a 10 kW system and including the minimum electrical permit processing fee, and notes a maximum fee of $500. A Fire Prevention plan check review for a residential system, $85, is charged in addition.
How to file: No. Residential solar and battery backup permits are handled over the counter, by walk-in, Monday through Thursday from 8:30 a.m. to 3:30 p.m., and no permit is issued without an active City of Napa business license. The California Energy Commission's SB 379 data lists the City of Napa as without an automated solar permitting platform.
Automated permit platform: None named

Sources: City of Napa, Solar PV (Building Division), checked September 23, 2026; City of Napa, Master Fee Schedule effective July 1, 2025 (2.2.47a Residential Solar Photovoltaic Permit & Inspection; 6.11.17 Fire Prevention plan check review), checked September 23, 2026; California Energy Commission, Residential Solar Permitting Program data (SB 379 platform status as self-reported by each jurisdiction; data last updated August 3, 2026), checked September 23, 2026; Gov. Code §66015, checked September 24, 2026. Napa in the California Solar Cost Index sets this fee beside every other city's.

Solar in Napa: installs, leases and batteries

Home solar systems connected at Napa addresses: 704 in 2021, 826 in 2022, 765 in 2023, 401 in 2024 and 470 in 2025. So connections peaked in 2022 and 2025 ran 43% below that peak. Another 236 were connected from January to May 2026.

Of the 470 systems connected in Napa in 2025, 36% were leased or on a PPA, so a solar company owns them, and 64% belonged to the homeowner. 52% had a battery, about as often as the 55% statewide. The median Napa system was 6.32 kW, and 88 companies connected at least one.

Napa beside Napa County and Statewide, 2025
	Napa	Napa County	Statewide
Systems connected in 2025	470	740	145,404
Leased or on a PPA	36%	36%	45%
With a battery	52%	49%	55%
Median system size	6.32 kW	6.14 kW	6.15 kW
Median reported cost	$4.05/W (262)	$4.04/W (409)	$4.14/W (58,628)
Companies connecting systems	88	115	2,475

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

Napa 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).

MCE supplies generation for many Napa addresses while PG&E delivers and bills; your bill shows which. Source: MCE, About Us (member communities).

Before you compare proposals

The Napa project checks that change the decision

The City of Napa handles home solar permits over the counter by walk-in rather than through an automated platform, and it prices the permit at $472 plus an $85 fire review, so the permit process can shape a Napa schedule.

Ask the same three questions

Does the permit line include both the $472 permit and inspection fee and the $85 Fire Prevention review?
Does the installer hold an active City of Napa business license? The City issues no permit without one.
Does the savings estimate use MCE's generation credits, including its 10 percent Solar Bonus Credit, with PG&E's delivery charges?

Local checks

$472 plus a fire review

The Master Fee Schedule effective July 1, 2025 lists a residential solar permit and inspection at $472, based on a 10 kW system, with a $500 maximum noted. A Fire Prevention plan check review of a residential system adds $85.

Walk-in counter only

Residential solar and battery backup permits are issued over the counter, Monday through Thursday from 8:30 a.m. to 3:30 p.m. The CEC's SB 379 data lists the City of Napa without an automated permitting platform.

MCE's solar credits

MCE, which names the City of Napa among its members, adds a Solar Bonus Credit of 10 percent of export credits and pays balances over $200 by check, up to $5,000, after the spring cash-out.

Related decisions

Local sources and limits

City of Napa — Solar PV — verified 2026-09-23. Residential solar and battery backup permits over the counter by walk-in, Monday-Thursday 8:30 a.m.-3:30 p.m.; no permit without an active City of Napa business license.
City of Napa — Master Fee Schedule effective July 1, 2025 — verified 2026-09-23. 2.2.47a Residential Solar Photovoltaic Permit & Inspection: $472, based on 10 kW, including the minimum electrical permit processing fee, maximum fee $500; Fire Prevention residential PV plan check review $85, in addition to 2.2.47.
MCE — About Us (member communities) — verified 2026-09-23. MCE serves 38 member communities in Contra Costa, Marin, Napa and Solano counties; the communities named include Concord, Richmond, San Ramon and Napa. Vacaville is not among them.
MCE — Solar Billing Plan — verified 2026-09-23. Exports credited at the Energy Export Credit value plus an MCE Solar Bonus Credit of 10% of those credits; CARE/FERA solar credit of $0.05 per kWh; Solar Storage Credit of $10 to $20 a month for enrolled batteries; annual April-to-March cash-out at Net Surplus Compensation for balances over $200, up to $5,000.
California Energy Commission — Residential Solar Permitting Program data (SB 379) — verified 2026-09-23. Self-reported platform status per jurisdiction, data last updated August 3, 2026; the CEC says it does not certify compliance. Rows used for the Tier 3 cities: Santa Clara, Clovis, Berkeley, Concord, Richmond, San Clemente, Encinitas, San Marcos, Lakewood, Elk Grove, Mission Viejo, Victorville, Tulare, Yucaipa, Rocklin and Grass Valley (SolarAPP+); Glendale and Santa Barbara (custom platform); Saratoga and Vacaville (Symbium); Napa (without a platform); Gilroy, San Ramon, Redding and Yuba City (SolarAPP+); Windsor and Ventura (Symbium); Redwood City and Cupertino (SolarAPP+); Hollister (without a platform, deadline Sept 2024).

Before you sign

In Napa the middle half of reported costs spans $2.71 to $5.77 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 Napa contract follows.

Frequently asked questions

How much does solar cost in Napa?

About $25,600 for a 6.32 kW system, at the $4.05 per watt median that Napa owners reported (262 systems, January 2025 to May 2026; middle half $2.71 to $5.77). Source: CPUC DG Stats. No federal credit applies to a Napa system finished in 2026.

What does a solar permit cost in Napa?

$472 for a home rooftop system on Napa's published schedule (checked September 23, 2026); the state limit is $450 up to 15 kW under Gov. Code §66015.

Which utility serves Napa?

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

Sources

California Distributed Generation Statistics (CPUC), Interconnected Project Sites data set, data through May 31, 2026 — checked September 24, 2026
CPUC, California Solar Consumer Protection Guide — checked September 24, 2026
26 U.S.C. §25D(h) and (e)(8)(A), residential clean energy credit — checked September 24, 2026
Napa solar permitting — City of Napa, Solar PV (Building Division) — checked September 23, 2026
City of Napa, Master Fee Schedule effective July 1, 2025 (2.2.47a Residential Solar Photovoltaic Permit & Inspection; 6.11.17 Fire Prevention plan check review) — checked September 23, 2026
California Energy Commission, Residential Solar Permitting Program data (SB 379 platform status as self-reported by each jurisdiction; data last updated August 3, 2026) — checked September 23, 2026
California Government Code §66015(a), residential solar permit fees — checked September 24, 2026
MCE, About Us (member communities) — checked September 23, 2026
PG&E average residential rate — CPUC Public Advocates Office, Q2 2026 Electric Rates Report, p.8, 20 — checked November 9, 2026

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