Local zoning · Sonoma

Sonoma — Nonconforming Uses

Nonconforming Uses under the Sonoma local zoning and planning code, with the controlling citations.

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Last reviewed: July 2, 2026

Overview

This page summarizes how the City of Sonoma regulates nonconforming uses, nonconforming structures, and nonconforming parcels under Title 19 (Integrated Development Regulations and Guidelines). The controlling rules live in Chapter 19.82 (Nonconforming Structures, Uses and Parcels) and related tables/standards elsewhere in Title 19; key limits include when a nonconforming use is considered abandoned, what repairs or enlargements are allowed, and criteria that make a parcel a legal building site. See the development standards for dimensional rules and how they interact with nonconformities. § 19.82.010–060 govern the basics.

Note: this page sticks to Sonoma zoning/planning code rules (Title 19). For building-code compliance (Title 24) and required permits, consult the California Building Standards Code. California Building Standards Code

What the code requires (quick synthesis)

  • Continuation allowed but limited: a nonconforming use may be continued, transferred, or sold, but may not be enlarged or extended beyond the footprint it lawfully occupied before becoming nonconforming except where the code explicitly allows changes by permit. § 19.82.020(A).
  • Structural changes are constrained: additions to a structure that is nonconforming only as to height and setback may be allowed only via a conditional use permit (CUP) and only if additions do not exceed height limits or encroach further into setbacks; reconstruction that replaces more than 50% of original floor area or exterior wall length is treated as new construction. § 19.82.020(B).
  • Repair/value limits: ordinary maintenance is allowed so long as work does not exceed 50% of assessed value in any one-year period unless the commission approves more via CUP. § 19.82.020(B)(2).
  • Abandonment / loss of status: general rule is 1 continuous year of discontinuance → abandonment and loss of nonconforming status; there are shorter special rules for some uses (see wine tasting and cannabis). § 19.82.030.
  • Nonconforming parcels: a parcel that fails current access/area/width rules can still be a legal building site if it meets specific criteria (created via approved subdivision, legally created by deed before the zoning change, approved variance/lot-line adjustment, or partial government acquisition within set limits). Additional development limits apply (e.g., minimum widths and minimum areas for residential parcels created/transferred after 10/12/1976). § 19.82.050.
  • Special categories: wine tasting/wine bars and commercial cannabis have supplemental nonconforming rules (including a 60-calendar-day abandonment standard and owner notification requirements). § 19.82.060 and SMC 19.50.120(B).

District-by-district breakdown (how nonconformities interact with each zoning district)

Below are Sonoma districts where nonconforming rules commonly arise. For each district I list the district name in bold, a one-line purpose, the typical permitted uses (as shown in Title 19 tables), key dimensional standards you’ll need when comparing existing conditions to current rules, and where that district generally applies in the city. All district use lists and dimensional examples are drawn from Title 19 tables and area-specific tables illustrated in the code. Where the code refers to “use permit” or other procedures, those are SMC 19.54 references (see code).

R-L (Residential—Low)

  • Purpose: lower-density single-family residential neighborhoods.
  • Typical permitted uses: single-family and accessory residential uses, small agricultural activities where allowed by Table 2-1. Table 2-1 shows permitted residential uses for the R-L district.
  • Key dimensional standards (examples from area tables): typical front setback 20 ft, side 7 ft (one-story), rear 20 ft, FAR 0.35, site coverage 40%, height ~30–35 ft (area-specific tables vary—see SMC 19.40 and Tables 3-3 / 3-9). See SMC 19.40 and area tables.
  • Where it applies: residential neighborhoods mapped throughout the Southeast, Central-East and Northeast area tables; check the zoning map.

R-S (Residential—Small lot)

  • Purpose: moderate-density single-family neighborhoods and smaller lots.
  • Typical permitted uses: single-family, accessory units, limited agricultural/home-business uses. See Table 2-1.
  • Key dimensional standards: front setbacks 15–20 ft (area-dependent), side setbacks 5–7 ft, FAR 0.35, site coverage ~40%, height ~30 ft. Consult area-specific Table 3-9/3-10 for the exact neighborhood.

R-M (Residential—Medium)

  • Purpose: medium-density residential (small multifamily allowed).
  • Typical permitted uses: multifamily units (up to specified sizes), accessory dwellings, and compatible uses listed in Table 2-1. ADUs are permitted per SMC 19.50.090. Sonoma ADUs
  • Key dimensional standards: smaller rear/side setbacks allowed, FAR up to 0.50–0.60 in some areas, site coverage up to 60%, height commonly 30 ft (area-specific). See Tables 3-3 / 3-9.

MX (Mixed Use)

  • Purpose: blend residential and commercial uses in a center; encourage pedestrian-oriented, mixed-use buildings.
  • Typical permitted uses: residential (multifamily), Accessory Dwelling Units, live/work, retail, offices, artisans—mixed-use table lists permitted and conditional uses (Table 2-3). Change in existing nonconforming uses is subject to SMC 19.82.020.
  • Key dimensional standards: area-dependent FAR and coverage (often higher than pure residential), building placement close to street (zero to 15 ft in some core areas). See community-area tables and SMC 19.40.

C / CG (Commercial and General Commercial)

  • Purpose: retail, services, restaurants, and neighborhood commercial functions.
  • Typical permitted uses: general retail, grocery, restaurants (often UP), offices, some entertainment uses; wine tasting/wine bars are governed by WTUP rules and special nonconforming provisions. See Table 2-2 for district-specific allowances.
  • Key dimensional standards: setbacks and coverage vary by area; downtown/core may allow buildings close to street (zero to 15 ft); see area tables. Storefronts and signs have special rules—nonconforming signs are handled under Title 18.

Gateway (special commercial/mixed district)

  • Purpose: create a pedestrian-friendly entrance and transition to downtown; mixed uses encouraged with design controls. Gateway guidance and standards are described in the code’s district chapter and area-specific tables.
  • Typical permitted uses: higher-intensity commercial and mixed uses consistent with the Gateway chapter; design guidance discourages strip-style construction.
  • Key dimensional standards: in core areas, buildings placed close to the street (0–15 ft); two-story buildings are encouraged; consult chapter 19.32 for details.

Broadway Corridor (19.32)

  • Purpose: address design and infill specifically along Broadway; has its own project planning and design standards that affect allowable changes and review. See Chapter 19.32 for corridor-specific standards.

Notes on district tables and measurements: Title 19 contains area-by-area tables (e.g., Tables 3-3, 3-6, 3-9, 3-10) that set the dimensional standards used to evaluate whether a structure or parcel is nonconforming in that location—consult the table that corresponds to your area. Examples appear in SMC Tables referenced above.

Key code rules in one decision-ready table

Rule or decision point Requirement / limit (plain) Code reference
Can a nonconforming use continue? Yes — may be continued/transferred/sold but not enlarged beyond lawful pre-existing area. § 19.82.020(A)
Loss of nonconforming status (general) 1 continuous year of discontinuance → abandonment. § 19.82.030
Wine tasting / wine bars abandonment 60 calendar days discontinuance = abandonment; owners must notify City Clerk of ceasing/restarting. SMC 19.50.120(B) and § 19.82.020 (wine rules)
Commercial cannabis nonconforming rules Special continuation rules; 60 calendar days abandonment; owner notification required. § 19.82.060
Structural alteration limits Additions allowed only with CUP if nonconforming only as to height/setback; new construction if > 50% original floor area or exterior wall length replaced. § 19.82.020(B)(1)(c)
Maintenance / repair limit Normal repairs allowed unless they exceed 50% of assessed value in any one year (exceptions via commission). § 19.82.020(B)(2)
Rebuild after involuntary destruction May rebuild if damage verified > 50% of appraised value; must rebuild within 1 year; single-family dwelling has special one-year owner-only exception. § 19.82.020(D)
Nonconforming parcel tests Parcel is legal building site if: created in approved subdivision, created by deed before zoning change, approved variance/lot line adjustment (SMC 19.54.060), or partial government acquisition within limits. § 19.82.050(A)
Site plan review trigger Any alteration > 1,000 sq. ft. gross floor area requires site plan & architectural review (SMC 19.54.080). § 19.82.020(B)(4)

Practical guidance / plain-English interpretation (synthesis)

  • If you own or operate a use that became illegal under new zoning, you generally may keep operating so long as you do not increase the area or intensity of that use; moving the operation to occupy more of the building or site is treated as enlargement and is prohibited without an approved permit (CUP or other). § 19.82.020(A).
  • If the building itself is set back or taller than today's rules, modest repairs and maintenance are allowed; major rebuilding or replacement beyond 50% of floor area or exterior wall length typically converts the project to “new construction” and must meet current standards (or proceed through CUP/variances). § 19.82.020(B).
  • Be alert to special categories: wine tasting/wine bars and commercial cannabis have shorter abandonment windows (60 days) and additional notification requirements — don’t assume the standard 1‑year rule applies. SMC 19.50.120(B) and § 19.82.060.

Also consult related program pages early in project planning: Sonoma Design Review, Sonoma Development Standards, Sonoma Parking, Sonoma Overlay Districts, and Sonoma Historic Preservation where applicable.

Checklist (what an applicant must satisfy before changing/continuing a nonconforming use or repairing a nonconforming structure)

  • Confirm whether the parcel/structure/use is legally nonconforming (collect deed/subdivision records and the date the use/structure was established). § 19.82.050(A).
  • Determine whether the use has been discontinued; confirm continuous discontinuance period (general 1 year, 60 days for wine tasting/cannabis). § 19.82.030; § 19.82.060; SMC 19.50.120(B).
  • If proposing structural work, calculate whether proposed replacement/alteration will exceed 50% of original floor area or exterior wall length (if so, treated as new construction). § 19.82.020(B)(1)(c).
  • If the structure is nonconforming only as to height/setback and you propose additions, prepare to apply for a conditional use permit and demonstrate additions don’t exceed height or further encroach into setbacks. § 19.82.020(B)(1).
  • If work will exceed 1,000 sq. ft., prepare site plan & architectural review submittal (SMC 19.54.080). § 19.82.020(B)(4).
  • For commercial cannabis or wine tasting uses, comply with the extra operating and notification rules; if temporarily ceasing operations, file required notices to avoid presumptive abandonment. § 19.82.060; SMC 19.50.120(B).
  • Check overlays and historic-designation rules (these may limit reconstruction or require design review). See Sonoma Overlay Districts and Sonoma Historic Preservation.
  • Confirm building-code upgrades and seismic retrofit requirements with the building division (Title 24). California Building Standards Code

Risks & Ambiguities

Issue Why it matters What to verify
Whether a use has been “discontinued” Abandonment removes nonconforming rights (general 1 year, special 60‑day rules). § 19.82.030; § 19.82.060. Verify continuous operation records, business licenses, tax records, utility/occupancy evidence; for wine/cannabis, check notice filings.
Whether repair/replacement counts as “new construction” Replacement > 50% of floor area or exterior wall length is treated as new—then current standards apply. § 19.82.020(B)(1)(c). Obtain a qualified appraiser/architect calculation of original floor area and exterior wall length; confirm assessed value thresholds.
Parcel legal status and pre-existing creation A parcel not legally created under Subdivision Map Act may not qualify as a legal building site. § 19.82.050(A). Produce recorded deed, subdivision map, or variance/lot-line adjustment record; confirm creation date relative to zoning amendment.
Interpretation of “occupy a greater floor area” Moving operations inside the building or reconfiguring may be considered enlargement. § 19.82.020(A). Clarify existing footprint from building records and plan sets; ask planning staff whether the proposed layout is enlargement.
Conflicts with overlay/historic controls Historic designation or overlays can impose stricter rebuilding or demolition limits. Check Chapter 19.42 and overlay district rules; consult Historic Preservation Commission if building is a local resource.
Site plan, architectural review applicability Work > 1,000 sq. ft. triggers review; omission can delay permits. § 19.82.020(B)(4). Confirm gross floor area addition and whether design review is required (SMC 19.54.080).

Plain-English Summary

If your use, building, or lot in Sonoma predates today’s zoning and doesn’t meet current rules, Sonoma’s Title 19 lets the use/structure continue under limits: you can’t enlarge the nonconforming use or rebuild beyond certain thresholds without discretionary approvals, a structure that sits too close or tall can be maintained but not extensively rebuilt (more than 50% replacement usually becomes “new construction”), and if the use stops for the legally prescribed period (commonly one year; some uses 60 days) you lose the nonconforming right and must comply with current zoning. § 19.82.020–050 summarize these rules.

Source References

  • SMC § 19.82.010 – Purpose of chapter (Nonconforming Structures, Uses, and Parcels).
  • SMC § 19.82.020 – Restrictions on nonconforming uses and structures (continuation, enlargement limits, maintenance/repair, seismic/code compliance, site plan review threshold).
  • SMC § 19.82.030 – Loss of nonconforming status (abandonment rules).
  • SMC § 19.82.040 – Nonconforming signs (see SMC Title 18 for sign rules).
  • SMC § 19.82.050 – Nonconforming parcels (criteria for legal building site and limitations).
  • SMC § 19.82.060 – Nonconforming commercial cannabis businesses (special continuation, 60-day abandonment, notice requirements).
  • District tables and dimensions: Table 2-1, Table 2-2, Table 2-3, and area-specific tables (e.g., Tables 3-3, 3-6, 3-9, 3-10) in Title 19 for permitted uses and area dimensional standards.
  • CUP, use permit, variance and review process references: SMC 19.54.040 (Use Permits), SMC 19.54.060 (Variances / Lot Line Adjustments), SMC 19.54.080 (Site Plan & Architectural Review) as referenced in the nonconforming rules.

For design review, parking, overlays, ADUs, and construction code interactions, consult:

Sources

Retrieved passages

  • Sonoma Zoning Code (§ 3) High relevance
  • CBC § 4 (Title 19) High relevance
  • Sonoma Zoning Code (§ 3) High relevance
  • Sonoma Zoning Code (Title 19) High relevance
  • Sonoma Zoning Code (Title 18) High relevance
  • Sonoma Zoning Code (§ 3) High relevance
  • Sonoma Zoning Code (Chapter 19.56) High relevance
  • Sonoma Zoning Code (Title 19) High relevance
  • Sonoma Zoning Code (Chapter 2.44) High relevance

Cited sections

Frequently asked questions

What happens if my nonconforming use stops operating for a long time?

If a nonconforming use is discontinued for a continuous period of one year, the code conclusively treats the use as abandoned and you lose nonconforming status; further use must comply with current zone rules (special shorter abandonment periods—60 days—apply for wine tasting and commercial cannabis). § 19.82.030; § 19.82.060.

Can I add a room or expand a building that is nonconforming only in setback or height?

Potentially — additions to a structure that is nonconforming only as to height and setback may be allowed, but only with a conditional use permit and only if the new work does not exceed height limits or encroach further into setbacks; also work cannot enable expansion of a nonconforming land use. § 19.82.020(B)(1).

If I repair fire damage, can I rebuild a nonconforming structure?

Yes in many cases: reconstruction after involuntary damage greater than 50% of appraised value may be permitted provided the reconstruction occurs within one year and has no greater floor area than the damaged structure; single-family dwellings have a specific one-year owner-only rebuilding exception. § 19.82.020(D).

Is there a dollar-value limit on repairs to a nonconforming building?

Normal maintenance and repairs are allowed provided the work does not exceed 50% of the assessed value of the structure in any one-year period; more extensive work may be allowed by the commission via CUP. § 19.82.020(B)(2).

My lot is smaller than current code requires—can I still build?

A parcel that doesn’t meet current access/area/width standards may still be a legal building site if it meets one of the tests listed in § 19.82.050 (approved subdivision, recorded deed before the zoning amendment, variance/lot-line adjustment, or partial government acquisition within limits). The applicant must provide evidence. § 19.82.050(A).

Does a nonconforming sign fall under Chapter 19.82?

No — nonconforming signs are handled by SMC Title 18, not Chapter 19.82; check Title 18 for sign amortization, repair, and replacement standards. § 19.82.040 points you to Title 18.

If I change tenants in a building with a nonconforming use, does that end nonconforming status?

Not automatically. A nonconforming use may be transferred or sold and continued (the use itself can remain), but you may not add additional uses on the site unless the nonconforming use is discontinued or brought into conformance; changes that enlarge occupied floor area are restricted. § 19.82.020(A).

Will historic district or overlay rules make it harder to rebuild a nonconforming structure?

Yes — overlay districts and historic preservation rules can impose additional restrictions; Chapter 19.42 and the Historic Preservation Commission’s procedures may apply. Verify whether the property is designated and consult the Historic Preservation Commission.

Are wine tasting rooms treated the same as other nonconforming commercial uses?

No — wine tasting facilities and wine bars have a separate special set of rules (WTUP requirements, operating-hour limits, a 60‑day abandonment rule, and an owner-notification requirement when operations cease). See SMC 19.50.120(B) and related nonconforming rules.

If my proposed alteration adds 1,200 sq. ft., what extra review is triggered?

Alterations that exceed 1,000 sq. ft. gross floor area require site plan and architectural review under SMC 19.54.080, in addition to any zoning/conditional use approvals that apply to the nonconforming status. § 19.82.020(B)(4).

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