# Seismic retrofit (foundation) cost in Marin County | Costolio URL: https://costolio.com/home/seismic-retrofit-foundation-cost/marin-county/ Updated: 2026-11-02 # Seismic retrofit (foundation) cost in Marin County In Marin County, the median declared value on 116 seismic retrofit (foundation) permits issued 2022-01-04 to 2026-10-20 was $9,422, according to Building Permit permit data (checked 2026-11-02). n = 116 permits Median$9,422 25th percentile$6,000 75th percentile$37,825 ## Seismic retrofit (foundation) cost in Marin County: permit figures 116 permits · 2022-01-04 to 2026-10-20 · [Building Permit](https://data.marincounty.gov/d/mkbn-caye) | Figure | Value | | Median | $9,422 | | 25th percentile | $6,000 | | 75th percentile | $37,825 | How this was counted116 permits · 2022-01-04 to 2026-10-20 · Source: [Building Permit](https://data.marincounty.gov/d/mkbn-caye) · Filter: https://data.marincounty.gov/resource/mkbn-caye.json?$where=issued_date >= '2022-01-01' (paged by :id) ; rule: keyword /SEISMIC|SOFT[- ]STORY|CRIPPLE WALL|BRACE (AND|&) BOLT|EARTHQUAKE BRAC|FOUNDATION (BOLT|ANCHOR|RETROFIT|REPAIR|REPLACE|UPGRADE)|ANCHOR BOLT|SILL PLATE ANCHOR|\bEBB\b/ AND NOT /EARTHQUAKE (SHUT|VALVE)|SEISMIC (GAS|VALVE|SHUT)|STRAP|WATER HEATER|SOLAR|NEW (SFD|S\.?F\.?D|SINGLE[- ]FAMILY|DWELLING|HOUSE|HOME|BUILDING|\d+[- ]STORY|DUPLEX|CONDO|APARTMENT)|ADDITION|\bADU\b|REMODEL|TENANT|SIGN/ ; residential only ; cost>0 · Pulled: 2026-11-02T14:19:22-08:00 · Checked on: 2026-11-02 · Contains data from Marin County (all jurisdictions in dataset), made available under the [Open Data Commons ODbL](https://opendatacommons.org/licenses/odbl/1-0/) ## What a seismic retrofit (foundation) permit usually covers Bolting the house to its foundation and bracing cripple walls. Usually anchor bolts, cripple wall bracing and hardware the inspector checks. Engineering reports, foundation replacement and finish work are often separate. ## Seismic retrofit (foundation) in Marin County compared with other places Among the 5 places where we have seismic retrofit (foundation) figures, Marin County has the median at position 2 from lowest. Lower medians: Los Angeles. Higher medians: San Diego, Santa Monica, Elk Grove. Other Marin County projects with figures: Water heater replacement, Electrical panel upgrade, Pool installation. Read this first. Permit values are self-reported by the applicant to set permit fees. They often leave out materials or labor, and they are not what the contractor actually charged. A quote above or below this range can be reasonable. ## About this Marin County sample - 116 permits after dropping $0 or blank values (1% of keyword matches had no cost) - cost field construction_value in Building Permit - permits issued 2022-01-04 to 2026-10-20 ## Seismic retrofit (foundation) permits in Marin County by year 50 of these permits were issued in 2025, the busiest year in this sample. Counting only full years, the number of permits went about the same in 2023, then up in 2024, then up in 2025. The median declared value went up in 2025. 2022 and 2026 are partial years here, so their counts are lower. Seismic retrofit (foundation) permits and median in Marin County by year | Year issued | Permits | Median | | 2022 | 8 | fewer than 30 permits | | 2023 | 8 | fewer than 30 permits | | 2024 | 33 | $8,000 | | 2025 | 50 | $24,100 | | 2026 | 17 | fewer than 30 permits | By month issued, the busiest months were July, November, August, and the quietest were April, December, May. ## What the Marin County seismic retrofit (foundation) permits describe We read the description each applicant wrote, leave out the standard wording the city adds to every permit, and sort the permit by the words it uses. The permit type the city chose is not used here. Where the description does not say, we count it as not stated. The most common kind here is seismic, scope not given. - Seismic, scope not given: 52 permits (45%), median $6,000 - Foundation work: 35 permits (30%), median $35,000 - Brace and bolt or cripple wall: 20 permits (17%) - Soft-story retrofit: 9 permits (8%) ## Other work listed on the same Marin County permits Out of 116 Marin County seismic retrofit (foundation) permits with a description of their own, 2 (1.7%) also mention plumbing; 1 (0.9%) also mention windows or doors. ## How we matched seismic retrofit (foundation) permits in Marin County Marin County has no permit type for this work, so we count a permit when its description mentions seismic, soft-story, cripple wall, brace and bolt or foundation bolting and repair. We leave out permits whose description mentions earthquake gas shut-off valves, seismic gas shut-off valves, water heater straps, water heaters, solar, new homes and buildings, additions, ADUs, remodels, tenant work or signs. We keep only permits for homes, not commercial buildings, and only permits with a declared value above $0. Counted from the same 116 permits as the figures above (2022-01-04 to 2026-10-20). Source: [Building Permit](https://data.marincounty.gov/d/mkbn-caye). Contains data from Marin County (all jurisdictions in dataset) ([source](http://www.socrata.com/terms-of-service)), made available under the [Open Data Commons ODbL](https://opendatacommons.org/licenses/odbl/1-0/). Figures derived from it are shared under the same license (share-alike). ## Related - [Seismic retrofit (foundation) in Elk Grove](https://costolio.com/home/seismic-retrofit-foundation-cost/elk-grove/) - [Seismic retrofit (foundation) in Los Angeles](https://costolio.com/home/seismic-retrofit-foundation-cost/los-angeles/) - [All costs in Marin County](https://costolio.com/home/cities/marin-county/) - [Compare my quote with permit records](https://costolio.com/home/quote-check/?project=seismic-retrofit-foundation&city=marin-county) [Got a quote?See where it sits next to these permit values.](https://costolio.com/home/quote-check/?project=seismic-retrofit-foundation&city=marin-county)