What actually requires a permit, what it costs, how long each jurisdiction takes, and why unpermitted work is far more expensive to inherit than to avoid.
Last updated August 13, 2026. Figures reflect real project pricing across Sonoma, Napa, Marin and Solano counties and are reviewed each season.
| Work | Permit? |
|---|---|
| Removing or altering any wall | Yes — always, load-bearing or not |
| New or relocated electrical circuits | Yes |
| Moving plumbing (sink, toilet, shower) | Yes |
| Water heater replacement | Yes |
| HVAC replacement or new ductwork | Yes |
| Windows — new opening or resize | Yes |
| Windows — like-for-like replacement | Usually yes (Title 24) |
| Re-roofing | Yes |
| Decks over 30" high or over 200 sq ft | Yes |
| In-ground pools and spas | Yes |
| Additions and ADUs | Yes |
| Garage conversion | Yes |
| Retaining walls over 4 ft | Yes |
| Solar installation | Yes |
| Painting, flooring, cabinets in place | No |
| Countertop replacement | No |
| Like-for-like fixture swap in same location | Usually no |
The trap in kitchen and bathroom remodels: homeowners often assume a "cosmetic" remodel is exempt. But if you add a circuit for a microwave, move a sink even a foot, or replace a fan with one that vents outside, you have crossed into permit territory. Most full kitchen and bathroom remodels require a permit.
| Project | Permit & plan check |
|---|---|
| Water heater or simple fixture | $150–$450 |
| Re-roof | $400–$1,200 |
| Kitchen or bathroom remodel | $600–$2,500 |
| Deck | $600–$3,500 |
| Pool | $3,500–$9,000 |
| Home addition | $6,000–$25,000 |
| ADU under 750 sq ft | $6,000–$18,000 (impact fees waived) |
| New single-family home | $45,000–$140,000 incl. impact fees |
Building permit fees are generally calculated from the valuation of the work. On top of the permit itself, larger projects may carry school impact fees, traffic and park fees, water and sewer connection charges, and plan check fees billed separately.
The single most important question is whether your property is inside a city boundary or in unincorporated county. They are different agencies with different fees, standards and timelines — and a Santa Rosa mailing address does not necessarily mean you are inside the City of Santa Rosa.
| Jurisdiction | Typical review time | Notes |
|---|---|---|
| City of Santa Rosa | 3–8 weeks | Large volume of fire-rebuild work since 2017 |
| Unincorporated Sonoma County | 4–12 weeks | Permit Sonoma; septic and well review common |
| City of Napa | 3–8 weeks | Design review in some districts |
| Unincorporated Napa County | 6–16 weeks | Agricultural preserve rules; strict on hillside |
| Calistoga / St. Helena / Yountville | 4–10 weeks | Small departments; historic overlays |
| Marin County | 6–16 weeks | Among the more demanding in the region |
The single biggest cause of permit delay is an incomplete submittal. Not a hostile plan checker — a drawing set missing a detail, a calculation, or a form. Time spent making the submittal complete is repaid several times over in review weeks saved.
Inspections are scheduled by your contractor and must be passed before the work is covered. A failed inspection is not a crisis; it means a correction and a re-inspection. What is a genuine problem is covering work before it has been inspected, because it then has to be opened back up.
The reason to permit is not fear of enforcement. It is that unpermitted work becomes your problem at the worst possible moment.
It is fixable. The usual path is a records search at the building department to establish what was permitted, an assessment of what exists, then a retroactive permit application with drawings of the as-built condition. Some jurisdictions run amnesty programs. It is nearly always cheaper to resolve it deliberately than to have it discovered during escrow.
Sonoma County requires a permit for structural changes, new or relocated electrical circuits, plumbing relocation, water heater and HVAC replacement, re-roofing, new or resized windows, decks over 30 inches high or 200 square feet, pools, additions, ADUs and garage conversions. Purely cosmetic work such as painting, flooring, or countertop replacement generally does not require one.
Plan review typically takes 3 to 8 weeks inside the City of Napa and 6 to 16 weeks in unincorporated Napa County. Additions and new construction sit at the longer end, and at least one correction cycle is normal, adding another 2 to 6 weeks. Incomplete submittals are the most common cause of extended timelines.
California requires sellers to disclose known unpermitted work. Buyers commonly respond by requesting a price reduction, retroactive permitting, or removal of the work. Appraisers often exclude unpermitted square footage from valuation entirely, and lenders may decline to count it, which can affect both sale price and the buyer's financing.
Yes, retroactive permits are generally available, but the completed work has to be verified against current code. That usually means opening walls to expose framing, electrical and plumbing for inspection, then correcting anything non-compliant. The total cost commonly runs two to four times what permitting the work correctly at the time would have cost.
Yes. Water heater replacement requires a plumbing permit in virtually every California jurisdiction, because it involves gas or electrical connections, seismic strapping, venting and expansion control. The permit is inexpensive, typically $150 to $450, and the inspection confirms the seismic strapping and venting are correct.
Your licensed contractor should pull the permit. An owner-builder permit shifts legal responsibility for the work onto you, including liability for injuries and for code compliance. If a contractor asks you to pull the permit instead, it frequently indicates they are unlicensed or unwilling to have the work inspected under their own license.
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