For a 40-year-old driver with a clean record, car insurance across all 16 ZIP codes we price in Sonoma County, including Santa Rosa and Petaluma, averages about $276 a month ($3,314 a year) for full coverage, based on the rates insurers had filed with state regulators as of Aug. 31, 2026. That’s 17% below the California average of $332 a month. GEICO has the lowest full-coverage average of the five major insurers we compared (Allstate, CSAA, Farmers, GEICO and State Farm), at about $180 a month.
Santa Rosa, the Sonoma County seat, averages about $284 a month across its six ZIP codes, the most of the 10 Sonoma County cities and towns we price, and Petaluma, about 15 miles south, averages about $270. Cotati costs the least of the 10, at $264.
Across the 16 ZIP codes, full coverage runs from about $264 a month in 94931, in Cotati, to $299 in 95407, in southwest Santa Rosa.
Cost data comes from the auto rates insurers file with state regulators, priced across all 16 Sonoma County ZIP codes in our data, compiled by Quadrant Information Services and updated as new rates are filed.
Rates as of Aug. 31, 2026. Page reviewed Oct. 7, 2026.
How Much Is Car Insurance in Santa Rosa–Petaluma, CA?
Full coverage in Santa Rosa–Petaluma averages $3,314 a year, or about $276 a month, for our benchmark driver. Liability-only coverage at 15/30/5 limits averages $1,149 a year ($96 a month), and 50/100/50 liability with comprehensive and collision averages $3,115 ($260 a month).
- Full coverage (100/300/100, $500 deductibles): $3,314 a year ($276 a month)
- 50/100/50 with $500 deductibles: $3,115 a year ($260 a month)
- Liability only (15/30/5): $1,149 a year ($96 a month)
- Santa Rosa: $3,412 a year ($284 a month) for full coverage
- Petaluma: $3,240 a year ($270 a month) for full coverage
- California average: $3,979 a year ($332 a month) for full coverage
- ZIP code range: $264 (94931) to $299 (95407) a month for full coverage
Cheap Car Insurance in Santa Rosa–Petaluma: Companies Compared
- Lowest average in our data, full coverage: GEICO, at about $180 a month ($2,161 a year).
- Next lowest among the five major insurers we compared: CSAA (AAA Northern California), at about $195 a month, then State Farm at $283.
- Liability only (15/30/5): CSAA and GEICO, effectively tied at about $45 and $46 a month.
- Also on our list: USAA at about $188 a month, Mercury at $216, Progressive at $221, Travelers at $294 and Nationwide at $305 (USAA sells only to military families).
- Most expensive in our data: Farmers, at about $378 a month, $2,379 a year more than GEICO for the same driver and car.
GEICO has the lowest full-coverage average among the five insurers in our Santa Rosa–Petaluma rate data. Statewide, five of the eight published 2026 California rate studies we reviewed rank GEICO cheapest for full coverage, apart from USAA, which sells only to military families, and a sixth ties GEICO with Progressive. For liability-only coverage at 15/30/5 limits, CSAA and GEICO are effectively tied for the lowest average, at about $45 and $46 a month.
Full-coverage averages by insurer in Santa Rosa–Petaluma
Monthly, for the same driver and car. Insurers marked with an asterisk in the table below aren’t in the chart.
Rates insurers filed with state regulators, compiled by Quadrant Information Services, as of Aug. 31, 2026. Benchmark 40-year-old driver, 100/300/100 with $500 deductibles.
| Insurance Company: | Liability Only 15/30/5 (Yearly): | Liability Only 15/30/5 (Monthly): | Full Coverage (Yearly): | Full Coverage (Monthly): |
|---|---|---|---|---|
| GEICO | $551 | $46 | $2,161 | $180 |
| CSAA (AAA Northern California) | $542 | $45 | $2,345 | $195 |
| State Farm | $1,342 | $112 | $3,401 | $283 |
| Allstate | $1,618 | $135 | $4,122 | $344 |
| Farmers | $1,694 | $141 | $4,540 | $378 |
| USAA (military families)* | $852 | $71 | $2,261 | $188 |
| Mercury Insurance* | $1,039 | $87 | $2,592 | $216 |
| Progressive* | $928 | $77 | $2,654 | $221 |
| Travelers* | $1,509 | $126 | $3,530 | $294 |
| Nationwide* | $1,407 | $117 | $3,663 | $305 |
| Santa Rosa–Petaluma average | $1,149 | $96 | $3,314 | $276 |
This table uses Sonoma County ZIP codes only. See how we calculated these rates. Your own price depends on your car, driving record and coverage, so compare car insurance quotes before you buy.
Santa Rosa–Petaluma Car Insurance Rates by ZIP Code
Across the 16 Sonoma County ZIP codes we price, full coverage for our driver ranges from about $264 a month in 94931 to $299 in 95407, a gap of $418 a year. Santa Rosa’s 95407 is the most expensive ZIP code in the county in our data, about $14 a month above the next, and the other Santa Rosa ZIP codes average about $277 to $285. Petaluma’s two ZIP codes average about $267 and $273.
Lowest-priced Sonoma County ZIP codes
Highest-priced Sonoma County ZIP codes
Search the table for your ZIP code. The last column shows how far each ZIP code is above or below the Sonoma County average.
| ZIP Code: | Liability Only 15/30/5 (Yearly): | Liability Only 15/30/5 (Monthly): | Full Coverage (Yearly): | Full Coverage (Monthly): | Full Coverage vs. Sonoma County Average: |
|---|---|---|---|---|---|
| 94928 (Rohnert Park) | $1,144 | $95 | $3,296 | $275 | About average |
| 94931 (Cotati) | $1,161 | $97 | $3,165 | $264 | -4% |
| 94952 (Petaluma) | $1,156 | $96 | $3,205 | $267 | -3% |
| 94954 (Petaluma) | $1,147 | $96 | $3,275 | $273 | -1% |
| 95401 (Santa Rosa) | $1,204 | $100 | $3,423 | $285 | +3% |
| 95403 (Santa Rosa) | $1,185 | $99 | $3,399 | $283 | +3% |
| 95404 (Santa Rosa) | $1,159 | $97 | $3,412 | $284 | +3% |
| 95405 (Santa Rosa) | $1,185 | $99 | $3,334 | $278 | +1% |
| 95407 (Santa Rosa) | $1,171 | $98 | $3,583 | $299 | +8% |
| 95409 (Santa Rosa) | $1,142 | $95 | $3,320 | $277 | About average |
| 95425 (Cloverdale) | $1,070 | $89 | $3,226 | $269 | -3% |
| 95436 (Forestville) | $1,175 | $98 | $3,362 | $280 | +1% |
| 95448 (Healdsburg) | $1,134 | $95 | $3,331 | $278 | +1% |
| 95472 (Sebastopol) | $1,096 | $91 | $3,191 | $266 | -4% |
| 95476 (Sonoma) | $1,136 | $95 | $3,254 | $271 | -2% |
| 95492 (Windsor) | $1,126 | $94 | $3,247 | $271 | -2% |
Your ZIP code matters
How Much More Does Better Coverage Cost in Santa Rosa–Petaluma?
Raising liability limits from 50/100/50 to 100/300/100 adds about $199 a year on average in our Santa Rosa–Petaluma data, with the same $500 deductibles. That’s about $17 a month for double the per-person injury limit, three times the per-crash limit and double the property damage limit, and the full-coverage package also raises uninsured and underinsured motorist coverage to 100/300.
Is Car Insurance Going Up in Santa Rosa–Petaluma?
For our benchmark driver, full coverage isn’t going up. Comparing the four insurers that are in both sets of rates, in the same Sonoma County ZIP codes, their full-coverage average fell from $3,136 a year nine months earlier to $3,007 in rates as of Aug. 31, 2026, a 4.1% drop. State Farm cut its Sonoma County average 13.1%, while Allstate’s, CSAA’s and GEICO’s averages were unchanged. Farmers is new in our rates over the past nine months, so it’s left out, which is why these averages differ from the Santa Rosa–Petaluma average above. Liability-only coverage at 15/30/5 limits rose 7.2%, led by State Farm, which raised its liability-only average 25.5%.
What Shapes Car Insurance Costs in Sonoma County
Sonoma County averages about $276 a month for full coverage, the 20th-least expensive of the 55 California counties we price. Marin County, to the south, averages $283 and Napa County, to the east, $288.
Prices vary more inside Santa Rosa than across the county: its ZIP codes run from about $277 to $299 a month, while the 10 towns we price run from $264 in Cotati to $284 in Santa Rosa. Sonoma, in the Sonoma Valley, averages $271 and Healdsburg $278.
How Santa Rosa–Petaluma Car Insurance Compares With Other California Cities
More California cities and towns are in the California rates by city table, and you can compare states on our car insurance rates by state page.
Napa, about 25 miles southeast of Santa Rosa, averages $280 a month, and Vallejo, about 35 miles southeast, $313. San Francisco, about 50 miles south, averages $350.
What Car Insurance Is Required in Santa Rosa–Petaluma?
Drivers in Sonoma County follow California’s rules. The minimum rose for policies issued or renewed on or after Jan. 1, 2025, and every policy must now carry at least:
- Bodily injury liability of $30,000 per person and $60,000 per crash
- Property damage liability of $15,000 per crash
Our California requirements guide covers uninsured motorist coverage, proof of insurance and the penalties for driving uninsured.
How to Lower Your Car Insurance Rate in Santa Rosa–Petaluma
- Compare GEICO and CSAA first. They have the two lowest full-coverage averages among insurers anyone can buy from in our Sonoma County data, about $180 and $195 a month.
- Quote several insurers. In our Sonoma County data, the lowest and highest insurer averages are about $198 a month apart for the same driver and car.
- Think twice before dropping comprehensive coverage. It’s the part of full coverage that pays when your car is damaged by fire, including wildfire, stolen or hit by a falling tree; liability-only coverage pays only for damage you do to others. In our Sonoma County data, full coverage costs about $180 a month more than liability only at 15/30/5 limits, which are below California’s 30/60/15 minimum, so weigh that against the cost of replacing your car.
- Compare at every renewal. Over the past nine months, State Farm has cut its Sonoma County average 13.1%, so the order in our table can shift.
- Ask about discounts and check your deductible. Many insurers lower rates for a clean driving record, paying in full or insuring more than one car, so ask which discounts you qualify for. Our full-coverage prices use $500 deductibles. A higher deductible lowers your premium but means you pay more yourself after a claim; see how car insurance deductibles work.
- Bundle your car and home insurance. Many insurers discount both policies when you buy them together. Check California home insurance rates, and compare homeowners insurance quotes before you shop. Renters can often bundle a renters insurance policy too.
Ready to compare
How We Calculated Santa Rosa–Petaluma Car Insurance Rates
Insurers must file their rates and rating rules with each state’s insurance regulator. Quadrant Information Services uses those filings to calculate what each insurer would charge a specific driver, and InsuranceQuotes analyzes those prices. This page uses rates in effect on Aug. 31, 2026.
- Sample: 80 full-coverage premiums from five insurers across 16 ZIP codes in Sonoma County, plus the same number of liability-only and 50/100/50 premiums.
- Area: this page covers all 16 ZIP codes we price in Sonoma County, with mailing addresses in Santa Rosa, Petaluma, Cloverdale, Cotati, Forestville, Healdsburg, Rohnert Park, Sebastopol, Sonoma and Windsor.
- Driver: a single 40-year-old driver, licensed 24 years, with good credit and no accidents or violations, driving a 2024 Toyota Camry LE they own, for personal use.
- Coverage: full coverage is 100/300/100 liability with $500 comprehensive and collision deductibles and 100/300 uninsured and underinsured motorist coverage. We also price 50/100/50 with the same deductibles, and liability-only coverage at 15/30/5 limits, with 15/30 uninsured motorist coverage and no comprehensive or collision. California’s minimum has been 30/60/15 since Jan. 1, 2025, so our liability-only prices use lower limits than the law requires.
- Calculation: for each insurer we take its lowest eligible price in each ZIP code and average those prices across the ZIP codes. The overall average is the mean of every insurer-and-ZIP price. Monthly figures are annual premiums divided by 12 and rounded.
- Rankings: we name a cheapest insurer only where it’s priced in at least half the ZIP codes and its lead over the next insurer isn’t so wide that it looks like an outlier. Annual prices within 3% of each other are called effectively tied.
- Rate changes: we compare the same insurer in the same ZIP codes, for the same driver and coverage, in rates as of Nov. 30, 2025, and Aug. 31, 2026. Farmers is new in our rates since November 2025, so it’s left out of rate-change comparisons; the other four insurers, Allstate, CSAA, GEICO and State Farm, are in both sets of rates. Rate-change percentages are calculated from the annual premiums shown; other percentages use the rounded monthly figures.
- Insurers marked *: priced from published 2026 California rate studies, scaled to our benchmark driver. They aren’t included in our averages or rankings.
- What this isn’t: a quote. These are modeled prices for one driver profile, calculated from insurers’ rate filings. Your price depends on your ZIP code, vehicle, driving record, coverage choices and discounts.
Coverage requirements come from California law and the California Department of Insurance. We refresh these figures when new rate data is released.
Santa Rosa–Petaluma Car Insurance FAQ
For our benchmark driver, full coverage in Santa Rosa–Petaluma averages about $276 a month ($3,314 a year) and liability-only coverage at 15/30/5 limits about $96 a month, based on the rates insurers had filed with state regulators as of Aug. 31, 2026. Full coverage is 17% below the California average of $332 a month.
GEICO has the lowest full-coverage average in our Santa Rosa–Petaluma rate data, at about $180 a month, with CSAA close behind at $195 among insurers anyone can buy from. USAA*, which sells only to military families, is priced at about $188 a month from published rate studies. For liability-only coverage at 15/30/5 limits, CSAA and GEICO are effectively tied for the lowest average in our Santa Rosa–Petaluma data. Statewide, five of the eight published 2026 California rate studies we reviewed rank GEICO cheapest for full coverage, apart from USAA, and a sixth ties GEICO with Progressive. Rates vary by driver, so compare quotes for your own car and ZIP code.
For our benchmark driver, a full-coverage policy (100/300/100 liability with $500 deductibles) averages about $284 a month ($3,412 a year) across Santa Rosa’s six ZIP codes. A policy with 50/100/50 liability and the same deductibles averages about $267, and liability-only coverage at 15/30/5 limits about $98. In Petaluma, full coverage averages about $270.
In our data, 94931, in Cotati, has the lowest full-coverage average in Sonoma County, at about $264 a month, and 95407, in Santa Rosa, the highest, at about $299. The ZIP code table on this page lists all 16 with the town for each.
In our Santa Rosa–Petaluma data, full coverage (100/300/100 with $500 deductibles) averages about $276 a month and liability-only coverage at 15/30/5 limits about $96, a difference of about $180 a month ($2,165 a year). Liability-only coverage won’t pay to repair or replace your own car after a crash, a theft or a storm. California law doesn’t require full coverage, but a lender or leasing company may.
Not for full coverage, for our benchmark driver. Comparing the four insurers in both sets of rates (Farmers is new over the past nine months), their Santa Rosa–Petaluma full-coverage average fell 4.1%, from about $3,136 to $3,007 a year. That’s lower than the Santa Rosa–Petaluma average of $3,314 because it leaves out Farmers. State Farm cut its Santa Rosa–Petaluma average 13.1%. Liability-only coverage at 15/30/5 limits rose 7.2%.
For our benchmark driver, full coverage in Santa Rosa–Petaluma averages about $276 a month. Nearby, Napa averages about $280, Vallejo–Fairfield about $291 and San Francisco about $350. Santa Rosa–Petaluma is the least expensive of these; prices depend mostly on ZIP code, so compare quotes for your own address.
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Michael Giusti is a senior insurance analyst, business journalist, and university professor with over 20 years of experience. He serves as department chair at Loyola University New Orleans and contributes to Insurance Thought Leadership, U.S. News, and other leading financial outlets.
