San Dimas Zoning, Planning & Building Codes

Last reviewed: July 3, 2026

Overview

San Dimas’s land-use rules are codified primarily in Title 18 of the San Dimas Municipal Code (the city’s zoning title) and a set of adopted Specific Plans and overlays that replace or supplement the base zoning in targeted places. Title 18 organizes the city’s base zones, development standards, review rules and special plan chapters; Specific Plans (for example, downtown and several numbered plans) provide area‑specific land‑use and design rules that supersede the base code where they apply. For quick practitioner navigation, know that design review and discretionary procedures are handled in Chapter 18.12, parking requirements live in Chapter 18.156, and accessory dwelling units are governed by Chapter 18.38 (ADUs) — see the code excerpts cited below for each point.

How San Dimas’s code is organized

• The city uses a central zoning title (referred to throughout the Specific Plans as Title 18) as the baseline code; Specific Plans say they follow Title 18 unless they state otherwise (for example, Specific Plan No. 7 references Title 18 explicitly) — § 18.510.050.A.
• Procedural and cross‑cutting chapters you will use frequently:
  • Design review / review authority — referenced throughout and handled under Chapter 18.12 (e.g., site plan and elevation approval requirements in the MHP and specific plans reference Chapter 18.12) — see § 18.122.070.
  • Parking rules — centralized in Chapter 18.156; many zone chapters defer to Chapter 18.156 for off‑street parking — see § 18.532.330.
  • Signs — Chapter 18.152 is the sign code (frequently cross‑referenced in specific plans) — see § 18.544.240.
  • Accessory dwelling units (ADUs) — Chapter 18.38 contains the city’s ADU/JADU rules and timelines — see § 18.38.010 and § 18.38.050.
  • Development standard overlays — created and mapped under Chapter 18.26 (DS overlays such as DS‑1, DS‑2 appear in the code with site‑specific rules) — see § 18.26.020.
  • Specific Plans — each Specific Plan is codified as its own chapter (examples below) and contains its own land‑use map, sub‑areas, and development standards; where a Specific Plan and Title 18 conflict the Specific Plan governs within its area — see § 18.50.020 through § 18.50.040.

(First internal links: the city’s central zoning landing and related topic pages)

• San Dimas’s primary zoning menu: San Dimas Zoning.
• For the citywide technical rules like setbacks and lot‑coverage, see San Dimas Development Standards.
• Parking rules are centralized; see San Dimas Parking.
• Design and project review is organized under the review procedures; see San Dimas Design Review.
• Overlays and specific overlay rules are governed via Chapter 18.26 and other overlay chapters; see San Dimas Overlay Districts.
• ADUs are implemented locally in Chapter 18.38; see San Dimas ADUs.
• The code points developers to the California building code for construction standards; see California Building Standards Code.
• For state housing statutes that alter local authority (ADU law, density bonus, SB‑9, etc.), see California housing laws and California ADU law.

Zoning district families (city‑level orientation)

San Dimas uses a mix of base zones, special districts and specific plans. The code is organized by chapter for many individual zones and by Specific Plan chapters for large project areas.

Key base / named districts you can find in the code:

• SF‑DR (Single‑Family Downtown Residential): the downtown single‑family residential zone — purpose and permitted uses are in § 18.35.010 and follow the development standards in the chapter.
• OS (Open Space): the OS district preserves natural/open space and sets use and development limits — see § 18.124.010 and § 18.124.020.
• MHP (Mobile Home Park): a planned‑park district with site‑plan and development plan approval and special findings — see § 18.122.070 and related MHP provisions.
• Business / industrial park forms appear in specific plan chapters as dedicated districts (for example, the Business Park district rules in Specific Plan No. 21 are described in § 18.534.150 and following).

What to expect in each district chapter: permitted uses, conditional/permitted uses, property development standards (setbacks, building separation, coverage), parking cross‑references, landscaping, signage and any design/architectural requirements. Many chapters defer technical parking rules to Chapter 18.156 and sign rules to Chapter 18.152.

Note: several neighborhoods and large redevelopment areas are controlled by Specific Plans (Downtown Specific Plan, Specific Plan Nos. 7, 9, 15, 20, 21, 24, etc.) — those are explained next and carry their own sub‑areas and rules.

Citywide development standards (high‑level practical guide)

San Dimas’s approach is to keep many technical standards in base zone chapters and cross‑reference centralized technical chapters for uniformity.

• Setbacks: base zones and plan chapters set setbacks by context. Example single‑family setbacks: Front: 20 ft (15 ft with swing‑in driveway), Side: 10 ft, Rear: none (UBC controls) in one chapter — § 18.32.090. For single‑family side‑yard easement lots the code provides Front 20 ft / 15 ft, Side 5 ft / easement and Rear 10 ft in § 18.24.050.
• Height limits: many base and plan chapters set maximum heights; typical small‑scale limits are 35 ft or two stories (e.g., § 18.32.120 and several specific plan chapters reference 35 ft maxima, with higher heights allowed only through conditional review) — see § 18.32.120 and § 18.540.220.
• Lot coverage / FAR: the code often caps lot coverage for single‑family areas at 35% (with limited exceptions raising to 40% for small lots or one‑story restricted parcels) — see § 18.24.050.F and development‑overlay rules that allow adjusted coverage in exchange for design limitations (DS overlays) — see § 18.24.050 and § 18.26.030. FAR (floor‑area‑ratio) is not generally spelled out in every zone chapter; where specific plan chapters adopt floor‑area controls they appear inside that Specific Plan’s Article for development standards (see the specific‑plan citations below).
• Parking: off‑street parking standards are implemented via Chapter 18.156; most districts and Specific Plans defer to Chapter 18.156 for counting and layout rules and then add project‑level overrides where necessary (see § 18.532.330 and repeated references in specific plan chapters). See San Dimas Parking for the topical landing.
• Landscaping / screening: Specific Plans and base zones require percent landscape cover and buffer strips; typical project standards call for 10% minimum landscaped coverage and continuous buffers where industrial/commercial abut residences — see § 18.532.320 and § 18.534.220.

(First mention link for development standards and landscaping)

• For consolidated development‑standards guidance see San Dimas Development Standards and for landscaping rules see San Dimas Landscaping and Screening.

Important practical note: many Specific Plans supersede or tailor these citywide standards inside their plan boundaries; always check both the plan chapter and the underlying Title 18 provisions — Specific Plans explicitly state that the Specific Plan governs within its boundaries and that Title 18 applies where the plan is silent — § 18.50.020 and § 18.50.040.

Specific plans & overlays (where rules change)

San Dimas has numerous codified Specific Plans and mapped overlay zones. Specific Plans are implemented as chapters in the municipal code and contain their own sub‑areas, permitted uses and standards.

• Downtown Specific Plan: establishes six sub‑areas (Gateway Village West/East, Transit Village, Town Core, Public/Semi‑Public and Open Space) and includes overlays (Town Core Commercial Overlay; Housing Element Sites Overlay). The Downtown Specific Plan is explicitly made applicable within the plan boundaries — see § 18.50.030 and § 18.50.020.
• Specific Plan Nos. 7, 9, 15, 20, 21, 24 (examples): each plan chapter contains location, purpose, land‑use map, and property development standards (setbacks, building coverage, height limits, landscaping, signage and architecture). For example, Specific Plan No. 7 notes that development “shall comply with the provisions of Title 18” unless specified and lays out the project area and objectives (§ 18.510.050); Specific Plan No. 24 authorizes commercial/industrial uses and cross‑references the Uniform Building Code for construction standards (§ 18.540.020–§ 18.540.040).
• Development Standard Overlays (DS‑1, DS‑2, etc.): Chapter 18.26 creates DS overlays that are appended to base zones on the official zoning map; overlays impose area‑specific limits (e.g., one‑story parcel minimums, increased coverage tied to one‑story limits) — see § 18.26.020 and the DS‑2 text in § 18.26.030 and exhibit language in the DS chapters.
• Scenic Highway and other overlays: scenic highway overlay rules (Chapter 18.108) add setbacks, landscaping and utility burial requirements where applied — see § 18.108.040.

(First mention link for overlays and historic preservation)

• For mapped overlays and their rules see San Dimas Overlay Districts and for locally important cultural resources consult San Dimas Historic Preservation.

Building permits & review — the practical permit path

• Ministerial vs discretionary: many small projects (including properly‑sized ADUs under Chapter 18.38) are processed ministerially with specific plan/ADU timelines; larger projects that require site plan or design review, conditional use permits (CUPs), tentative subdivision maps, or variances go through discretionary review bodies (planning director, planning commission, city council) per the chapter cross‑references (see § 18.38.050 for ADU ministerial timelines and § 18.122.070 plus Chapter 18.12 for required design/review submission lists).
• Design review: projects requiring architecture/site plan approval are reviewed under Chapter 18.12; many zone and specific plan chapters explicitly direct applicants to Chapter 18.12 for the required submittals and findings (e.g., § 18.122.070, § 18.534.140).
• Conditional use permits, variances and map procedures: Specific Plan amendments and many discretionary actions are processed per the code’s procedural chapters; Specific Plan amendments reference Chapter 18.208 for amendment procedure and other chapters reference the Subdivision Map Act and Title 17 for tract and parcel maps (e.g., § 18.50.050 and references to Title 17 procedures).
• Building permit & construction standards: the local code relies on the state/accepted building codes for construction standards; Specific Plans reference the Uniform Building Code and other adopted codes (see § 18.540.050.D), and ADU solar/energy rules reference the California Energy Code (Title 24) — see § 18.38.040.O. For building inspections and code compliance the city enforces the California building standards (Title 24).

(First mention link for building code)

• See California Building Standards Code for the state construction rules the city enforces.

State housing law in San Dimas (ADUs, SB‑9, density bonus, rent rules)

San Dimas has updated text and procedures that explicitly implement state ADU law and references state planning law elsewhere, but comprehensive local rules for every state housing statute are not always included in a single chapter. Key, local code‑level interactions:

• ADUs / JADUs — Chapter 18.38 implements ADU/JADU rules consistent with state law:

  • ADUs are allowed in any zone permitting single‑ or multi‑family uses; one ADU + one JADU per lot is allowed in residentially zoned properties — § 18.38.020.A.
  • Size and setback standards align with state minima: detached ADU maxs (generally 850–1,000 sq ft depending on type), minimum 4‑ft side/rear setbacks for ADUs, height limits (16 ft base for detached ADUs, with certain exceptions up to 18 ft) and ministerial plan review timelines (city must act within 60 days on a completed ADU application) — see § 18.38.040, § 18.38.050, and related subsections.
  • The ADU chapter also addresses meters, utility fees and connection rules — § 18.38.040.P.

• SB 9 (lot splits / two‑unit approvals) and other lot‑split/duplex statutes — Not found in the retrieved municipal text: I did not find a discrete chapter implementing SB 9 (ministerial lot splits/urban lot split standards) in the extracted materials. If you need a definitive answer about SB 9 implementation or local objective design standards for SB 9 approvals, verify with the Community Development Department or check the most recent adopted ordinances. (Information gap — see the Information Gaps section below.)

• Density bonus, affordability incentives, and rent control:

  • I did not locate a local density‑bonus implementation chapter or local rent‑control ordinance in the retrieved extracts. Density bonus is often handled via general plan/land‑use and affordable‑housing implementing ordinances; Specific Plans sometimes include affordable housing requirements and unit counts (e.g., some Specific Plan land‑use exhibits fix maximum units) — see Specific Plan chapters for site‑level language such as the unit caps in Specific Plan No. 15 — § 18.524.050.J. For rent control nothing in the provided excerpts establishes local rent control. Verify with the city clerk/community development for up‑to‑date adoption.

(First mention link for California housing law)

• For the statewide legal context and updates see California housing laws and California ADU law.

Practical orientation / checklist for applicants

1. Confirm zoning and overlays for the parcel on the city’s official zoning map and note any Specific Plan or DS overlay that may govern (Specific Plans/DS overlays explicitly supersede or amend Title 18 inside their boundaries) — see § 18.50.020 and § 18.26.020.
2. Check district chapter for permitted uses and base development standards (setbacks, coverage, max height). If in a Specific Plan chapter, consult the plan’s property development standards (e.g., Specific Plans Nos. 7, 15, 21, 24) — see each plan’s Article(s) on development standards (for example, § 18.510.050 and § 18.540.210).
3. Confirm parking counts (Chapter 18.156) and sign/landscape requirements (Chapters 18.152 and 18.14 / plan chapters) — these are repeatedly cross‑referenced in zone and plan chapters (see § 18.532.330 and § 18.544.230).
4. Determine review path: ministerial building permit (e.g., ADU ministerial path § 18.38.050) vs design review/site plan/CUP/variances processed under Chapter 18.12 and procedural chapters — check § 18.38.050 and § 18.122.070.
5. Check CEQA/environmental requirements: Specific Plans call out environmental review (EIR/initial study) where adopted — see § 18.540.040.H for an example.

Information Gaps

• The extracts show many zone and specific‑plan chapters, but I did not find a single consolidated index of every base zone label (for example, an explicit enumerated table listing R‑1, R‑2, C‑1, C‑2, etc., with their chapter numbers) in the retrieved snippets. A parcel‑level check against the official zoning map or the city’s municipal‑code index is recommended to find the precise base chapter for a conventional zone label (if you need a specific R‑designation chapter citation). (Not found in retrieved materials.)
• I did not find a local SB‑9 implementation chapter in the materials you supplied. If you need how San Dimas handles ministerial lot splits or duplex approvals under SB‑9, please confirm with Community Development or provide the ordinance file for review. (Not found in retrieved materials.)
• I did not find a local density‑bonus ordinance or a rent‑control ordinance in the extracted materials; confirm with the City for adopted local implementations or recent ordinances. (Not found in retrieved materials.)

Source References

• San Dimas Municipal Code — Title 18, Specific Plan applicability and downtown plan language: § 18.50.020 / § 18.50.030 / § 18.50.040.
• Specific Plan No. 7 (authority, scope, and Title 18 cross‑reference): § 18.510.030 – § 18.510.050.
• Specific Plan No. 24 (commercial/industrial area; UBC reference): § 18.540.020 – § 18.540.040.
• Business Park / Specific Plan No. 21 property standards (business park district): § 18.534.150 – § 18.534.220.
• Development Standard Overlay rules (DS‑1 / DS‑2): § 18.26.020 – § 18.26.030.
• Scenic Highway Overlay: § 18.108.030 – § 18.108.040.
• Mobile Home Park (MHP) review & design review cross‑reference to Chapter 18.12: § 18.122.070.
• City ADU chapter (standards, ministerial review timeline, size, setbacks, meters): Chapter 18.38 (notably § 18.38.010, § 18.38.020, § 18.38.040, § 18.38.050).
• Central parking cross‑reference examples (zones deferring to Chapter 18.156): § 18.532.330 and multiple plan chapters.
• Signage cross‑references in specific plans: § 18.544.240 (refers to Chapter 18.152).