Petaluma — Nonconforming Uses

Last reviewed: July 2, 2026

Overview

This page explains how the City of Petaluma regulates nonconforming uses, nonconforming structures, and nonconforming lots under the Petaluma Implementing Zoning Ordinance. The rules that control what you can change, rebuild, or resume for a use or structure that was legal when established but later became nonconforming are in Chapter 22 of the Ordinance — especially § 22.010 – § 22.050. See the citywide development and zone tables for the underlying district standards that determine when a use or structure is nonconforming (for example, setbacks, heights, and lot-size rules) — these are in Chapter 4 and related development tables.

Because many day-to-day questions about adding floor area, creating an ADU, or changing a business depend on the base zone standards, refer to the city zone tables and the Petaluma Development Standards and the Petaluma Zoning pages when you plan (links below used in-text: parking, design review, overlays, ADUs, building code). This page stays strictly to the local ordinance rules about nonconformities (Chapter 22) and ties them to the actual zone standards where relevant.

What the Ordinance says (core rules)

• Purpose: The city regulates nonconforming conditions to “control, reduce, or eliminate conflicts” and to provide an equitable removal process where public welfare is affected — § 22.010.

• Definitions:

  • Nonconforming Use — a use that was legal when established but no longer meets current district rules; uses that now require a use permit remain nonconforming until the permit is secured — § 22.020(A).
  • Nonconforming Structure — a structure legally built but not meeting current district rules (includes signs); structures that now require a use permit remain nonconforming until a permit is secured — § 22.020(B).

• General limitations: A nonconforming use or structure cannot be enlarged, extended, or moved to another part of the parcel except where limited reconstruction makes it conforming or where small alterations in residential districts would not increase the degree of nonconformity. Minimum allowable setbacks for certain rehabilitations are specified — § 22.030(A).

• Change of use: Switching from one nonconforming use to another nonconforming use requires Planning Commission approval and only to a use that is the same or more restricted in intensity — § 22.030(C).

• Abandonment / discontinuation:

  • A nonconforming use of a structure that is discontinued for 12 months or more cannot be re-established — § 22.030(D).
  • A nonconforming use of land (no structure except fences, signs, or buildings < 400 sq ft) that is discontinued for 3 months or more cannot be re-established — § 22.030(E).

• Damage and rebuilding: If a nonconforming structure is damaged by fire, flood, or “act of God” to an extent exceeding 50% of its value (as determined by a director‑approved methodology), it may not be restored except in a way that makes it conforming to the current district regulations — § 22.030(F).

• Maintenance: Ordinary maintenance and repairs are allowed; the Building Official may permit major structural work for public safety and must state reasons on any building permit issued — § 22.030(G).

• Fueling stations/gas stations: There is a tailored regime in § 22.035 that allows continued operation of lawful pre-existing fueling stations but restricts enlargements that increase fossil-fuel storage/dispensing; it also allows changes to improve environmental controls or to add electric/hydrogen charging without increasing fossil-fuel capacity. Some § 22.030 subsections still apply; others do not — § 22.035 (A–J).

• Performance standards / missing permits: Uses nonconforming because they violate performance standards must conform within 5 years of the ordinance adoption; uses nonconforming because they lack a use permit remain subject to § 22.030 until a permit is secured — § 22.040.

• Construction approved prior to the ordinance: Buildings with a valid building permit issued before the ordinance enactment may be completed and are then treated as nonconforming subject to the Chapter 22 restrictions — § 22.050.

District-by-district practical breakdown

Chapter 22 is citywide in application, but whether a specific structure or use is nonconforming depends on the base zone standards in Chapter 4. Below are the main Petaluma zones you will see most often, with the relevant typical permitted uses, key dimensional standards that commonly create nonconformities, and where the zone is applied. (For full allowed‑use lists and all numeric standards see the Chapter 4 tables cited after each district.)

Note: the nonconforming rules themselves are in Chapter 22 — see § 22.020 and § 22.030 for the controlling rules on whether and how you can alter, rebuild, or resume a use.

RR (Rural Residential)

• Purpose: Low‑density rural residential and agricultural edge lots.
• Typical permitted uses: Single‑family homes, accessory agriculture, limited agricultural structures.
• Key dimensional standards that create nonconformities: Minimum lot area 2 acres, minimum setbacks (see Table 4.7) — front/side/rear and height limits are in Table 4.7. Changes that increase nonconformity of setbacks are restricted under § 22.030(A).

R‑1 (Residential 1)

• Purpose: Typical single‑family neighborhoods.

• Typical permitted uses: Single‑family dwelling, accessory uses (home occupations, ADUs subject to Chapter 7).

• Key dimensional standards: Minimum lot area 20,000 sq ft; front setback 20 ft; side 5 ft; rear 20 ft (Table 4.7 / Table 4.8 references). If an existing house encroaches on these setbacks, it is a nonconforming structure and cannot be expanded in a way that increases the nonconformity (see § 22.030(A)); ADU conversions have special flexibility under § 22.030(B) and the ADU rules in Chapter 7.

• Practical ADU note: A nonconforming structure converted to an ADU may be reconstructed in place (same footprint and height); expansion (e.g., second story) triggers a minimum 4‑ft side/rear setback requirement — see § 22.030(B) and Petaluma ADU rules. Link to Petaluma ADUs for local ADU standards.

R‑2 / R‑3 (Residential 2 & 3)

• Purpose: Moderate‑density residential (duplexes, small multi‑family in R‑3).
• Typical permitted uses: Duplexes, small multi‑unit buildings (per Table 4.8).
• Key dimensional standards: R‑2 front setback 20 ft; side 5 ft; R‑3 front 15 ft; side 3 ft; rear 15 ft (Table 4.8). Nonconforming setbacks or lot sizes are common triggers for Chapter 22 restrictions; ADU rules potentially relax some nonconforming setback barriers when converting existing nonconforming structures — see § 22.030(B).

MU Zones (MU1A, MU1B, MU2, etc.) — Mixed Use

• Purpose: Ground‑floor retail and upper‑floor residential/office; encourage walkable urban form.
• Typical permitted uses: Restaurants, offices, small retail, upper‑floor housing (per Table 4.3).
• Key dimensional standards: Mixed‑use lot and height standards are in Table 4.3 and Table 4.x; permitted uses and when a CUP is required are shown in the MU tables. A commercial nonconforming use (for example, an existing retail operation in a transition area) remains subject to Chapter 22 rules on enlargement and change of use (§ 22.030(A, C)).

CF (Civic Facility)

• Purpose: Public buildings, institutional uses, community service facilities.
• Typical permitted uses: Libraries, community centers, schools (Table 4.13/4.5).
• Key dimensional standards: See Table 4.13 — e.g., principal building height 25 ft in some civic designations. Civic uses that predated a zoning change will be nonconforming uses subject to Chapter 22 limits on expansion/reconstruction (see § 22.030).

OSP / AG (Open Space & Agriculture)

• Purpose: Parks, open space, agricultural uses.
• Typical permitted uses: Parks, passive recreation, farm uses.
• Key dimensional standards: Table 4.6 sets modest setbacks (rear 5 ft shown) and heights (25 ft principal building example). An agricultural building legally constructed before a new zone change may be nonconforming and is governed by Chapter 22 restoration/repair and damage rules (§ 22.030(F–G)).

Fairgrounds Overlay Zone (FOZ) and other overlay districts

• Purpose: Special rules at the Fairgrounds and other overlay areas; overlays can restrict new uses and permit limited exceptions for existing uses. The Fairgrounds Overlay is referenced in Chapter 5 and conditions uses differently than base zones — check the overlay when assessing nonconforming status (Chapter 5 notes and Table citations). If a use is allowed in the base zone but banned by the overlay, that may create a nonconforming use — Chapter 22 still controls abandonment and changes — see Table notes and Chapter 5. Link to Petaluma Overlay Districts for local overlay guidance.

Quick decision table (what you can/can't do)

Checklist (what an applicant must satisfy)

• Verify whether the use or structure was legal when established and identify why it is nonconforming (use, structure, or lot) — § 22.020.
• Confirm the current base zone standards (Chapter 4 tables) that define the present nonconformity (setbacks, lot size, height) — see Table 4.x for your zone.
• For any proposed change, check whether the proposal enlarges/extents the nonconforming condition; if so, it is generally prohibited unless it conforms — § 22.030(A).
• If proposing an ADU conversion on a nonconforming structure, document whether the work is in‑kind (same footprint/height) or an expansion (expansion triggers 4‑ft setbacks) — § 22.030(B) and Chapter 7 ADU rules. Link to Petaluma ADUs.
• If proposing a change between nonconforming uses, prepare a Planning Commission application showing the new use is of the same or more restricted nature — § 22.030(C).
• If the structure was damaged, get a value determination per the director’s methodology before planning restoration; if damage >50%, the structure must be made conforming — § 22.030(F).
• For fueling stations, check § 22.035 for special allowances/limits (EV infrastructure allowed; increasing fossil‑fuel capacity prohibited) and whether § 22.030 subsections apply.
• Coordinate with Petaluma Parking and Petaluma Design Review early — nonconforming projects may still trigger parking or design review conditions.

Risks & Ambiguities

Plain-English Summary

If your house, sign, business, or lot used to meet the rules but no longer does because the zoning changed, it’s a “nonconforming” condition. Petaluma generally lets those conditions continue but stops owners from making them worse: you usually cannot expand or move the nonconforming part, long‑abandoned uses can’t restart, badly damaged buildings can’t be rebuilt unless they meet current rules, and special rules apply to fueling stations and to conversions to ADUs — see § 22.020–§ 22.050.

Source References

• Petaluma Implementing Zoning Ordinance — Chapter 22, Nonconforming Uses: § 22.010 Purpose; § 22.020 Definitions; § 22.030 Regulation of Nonconforming Uses and Structures; § 22.035 Fueling station rules; § 22.040 Performance‑standards and missing permits; § 22.050 Construction approved prior to ordinance.
• Petaluma Implementing Zoning Ordinance — Chapter 4 (Zone districts and development standards; Tables 4.6, 4.7, 4.8, 4.13, MU tables) for the base numeric standards that create nonconformity (setbacks, lot size, height).
• Petaluma Implementing Zoning Ordinance — Chapter 7 (Standards for Specific Land Uses), ADU provisions referenced re: setbacks and conversions (for interplay with § 22.030(B)).
• Petaluma Implementing Zoning Ordinance — Chapter 5 Fairgrounds Overlay Zone (overlay-specific restrictions that can create nonconforming uses relative to base zone).

Internal city topic pages linked above for planning steps and ancillary reviews: Petaluma Zoning, Petaluma Development Standards, Petaluma Parking, Petaluma Design Review, Petaluma Overlay Districts, Petaluma ADUs, Petaluma Land Use. Also see state references when ADUs interact with nonconformities and the California Building Standards Code where building permits and safety work are required.

Retrieved passages

• Petaluma Zoning Code (§ 3) High relevance show source text
• Petaluma Zoning Code (section shall) High relevance show source text
• Petaluma Zoning Code (Chapter 22) High relevance show source text
• Petaluma Zoning Code (Section 22.030) High relevance show source text
• Petaluma Zoning Code (section shall) High relevance show source text
• Petaluma Zoning Code (Section 10.100) High relevance show source text
• Petaluma Zoning Code (§ 4) High relevance show source text
• Petaluma Zoning Code (Section 22.030) High relevance show source text
• Petaluma Zoning Code (Chapter 10) Medium relevance show source text
• Petaluma Zoning Code Medium relevance show source text
• Petaluma Zoning Code (Chapter 1) Medium relevance show source text

Cited sections

• Petaluma Implementing Zoning Ordinance — Chapter 22, Nonconforming Uses: **§ 22.010** Purpose; **§ 22.020** Definitions; **§ 22.030** Regulation of Nonconforming Uses and Structures; **§ 22.035** Fueling station rules; **§ 22.040** Performance‑standards and missing permits; **§ 22.050** Construction approved prior to ordinance. (Chapter 22)
• Petaluma Implementing Zoning Ordinance — Chapter 4 (Zone districts and development standards; Tables 4.6, 4.7, 4.8, 4.13, MU tables) for the base numeric standards that create nonconformity (setbacks, lot size, height). (Chapter 4)
• Petaluma Implementing Zoning Ordinance — Chapter 7 (Standards for Specific Land Uses), ADU provisions referenced re: setbacks and conversions (for interplay with § 22.030(B)). (Chapter 7)
• Petaluma Implementing Zoning Ordinance — Chapter 5 Fairgrounds Overlay Zone (overlay-specific restrictions that can create nonconforming uses relative to base zone). (Chapter 5)
• Petaluma_ZoningCode.md
• 2025 California ADU handbook.md

• Official Petaluma code library