San Dimas — Signage

Last reviewed: July 2, 2026

Overview

San Dimas regulates signs primarily through the municipal sign chapter (chapter on signs collected in the zoning code) and specific-plan chapters that call back to that sign chapter. The city requires permits for most permanent signs, defines permitted temporary and exempt signs, sets safety/illumination rules (including electronic message board limits), and treats nonconforming signs with amortization rules. Key rules live in § 18.152.030–§ 18.152.080, with zone- and specific-plan level refinements in multiple chapters (examples below) .

Note: This page covers only what the San Dimas zoning/planning ordinance says about signage (not Title 24 / building-code structural or electrical specifics). For building-code obligations see the California Building Standards Code linked below.

How the sign rules are organized (quick map)

• Citywide technical and procedural rules: § 18.152 (definitions, permits, design specs, prohibited locations, nonconforming signs) .
• Residential single‑family sign rules referenced through specific plans: Chapter 18.156 / single‑family references (see specific-plan cross-references) .
• Project and complex-level sign programs and monument/entry-sign rules appear inside specific‑plan chapters (for example, Specific Plan No. 26 and No. 5 chapters) and in site-specific standards such as § 18.544.240 and § 18.532.350 (master sign program / entry monument provisions) .

Before applying, confirm whether the property sits in a base zone, a specific plan, or an overlay — that determines whether the citywide sign chapter applies directly or is modified by plan provisions. For design review procedures that often apply to sign programs see the city's San Dimas Design Review.

District-by-district breakdown

I-P (Industrial Park)

• Purpose: supportive of research, fabrication and administrative uses in a landscaped campus-like setting .
• Typical permitted uses: corporate/industrial park uses listed in the I-P chapter; signs allowed for complex identification and individual businesses as limited below .
• Sign rules (local highlights):
  • Complex identification (entry) signs are allowed up to 150 sq ft per face and up to 6 ft overall height at major entrances § 18.508.120(F)(1)(a–b) .
  • Individual business wall signs: one flush wall sign allowed; area limited to 2 sq ft per lineal foot of building frontage, and absolute cap 150 sq ft; material preference: sandblasted wood‑type (local design standard) § 18.508.120(F)(2)(a–c) .
• Where it applies: the I‑P zone parcels (see the I‑P chapter) and is enforced alongside design review (Chapter 18.12) .

C‑H (Highway Commercial)

• Purpose: manage signs and visual quality along major thoroughfares (e.g., Foothill, Arrow) and buffer adjacent residential areas .
• Typical permitted uses: commercial and retail; sign regulation follows the citywide sign chapter § 18.152 with additional site setback and landscape yard rules § 18.92.050(G) .
• Key dimensional/context rules: signs may be placed in required yards where expressly allowed; yard landscaping and buffers may be required § 18.108.050(A) and sign provisions apply by cross‑reference to § 18.152 .

Specific Plan No. 26 (Commercial / Specific Plan area)

• Purpose: create a high‑quality commercial/residential project with coordinated design and signage controls § 18.544.040 .
• Sign rules: the specific plan defers to the citywide sign chapter and in addition requires a master sign program be approved by the review authority before any sign is installed § 18.544.240 .
• Practical effect: even if a sign type is allowed by § 18.152, a project inside Specific Plan No. 26 must get a coordinated sign program approved under the project's design review procedures (Chapter 18.12) first .

Specific Plan No. 5 / Area 2 (Single‑family residential / rural feel)

• Purpose: very low‑density single‑family community; sign allowances are conservative to preserve rural character § 18.506.020 .
• Sign rules: signs within this specific plan are governed by the single‑family sign rules in Chapter 18.156 as called out in § 18.504.360 (i.e., residential sign chapter is applied to the area) .
• Typical permitted signage: directional/informational signs, nameplates and limited temporary signs as set in the single‑family sign chapter (see Chapter 18.156) .

Mobile Home Parks

• Sign rules: Mobile home parks must comply with Chapter 18.152 and must provide a park directory sign adjacent to the park administration building; additional on‑site directional signage is allowed as accessory § 18.532.190 and related mobile‑home-park provisions .

Key citywide sign requirements (decision-focused table)

Practical guidance & comparisons (plain English)

• The city’s sign chapter is the master control for most properties; zone chapters either repeat, reference, or narrow the citywide rules. When a specific plan exists (Downtown, Specific Plan No. 26, No. 5, etc.), that plan will often require a master sign program and design review before any sign permits are issued — budget time for design review under Chapter 18.12 and for approval of a coordinated sign program (see § 18.544.240 and design review standards) .
• Electronic signage is allowed but tightly regulated for brightness and content — San Dimas treats electronic message boards as special signs that must dim automatically, include fail‑safe behavior, and not be used for off‑site advertising (public‑service content is favored) § 18.152.060 .
• Smaller commercial centers in I‑P and similar plan areas get two tracks: a permitted maximum for complex identity signs (e.g., 150 sq ft / 6 ft tall) and per‑tenant wall sign area tied to building frontage (e.g., 2 sq ft per lineal foot, cap 150 sq ft) § 18.508.120(F) .
• Single‑family and rural specific‑plan areas look to the single‑family sign chapter (Chapter 18.156) and are more restrictive; for those properties check the specific‑plan cross‑reference like § 18.504.360 before assuming commercial sign rules apply .

Include design‑level coordination with landscaping (sign base plantings) and with parking and landscaping and screening plans because many zones require landscaped setbacks or buffer areas where signs sit (e.g., setback/landscape minimums in C‑H and several specific plans) . Also expect design review per San Dimas Design Review and potential overlay controls via the San Dimas Overlay Districts (historic overlays will bring extra restrictions; see historic sign exceptions for plaques) .

Practical note: if your proposal includes an ADU sign or directional signs that might interact with housing rules, consult the city's ADU guidance San Dimas ADUs and statewide ADU law California ADU law — the zoning sign chapter does not replace ADU-specific signage allowances (verify with the jurisdiction) .

Checklist

• Confirm base zone and whether the parcel sits inside a specific plan or overlay (e.g., Specific Plan No. 26, Downtown Specific Plan) — signage rules may be modified there § 18.544.040; § 18.50.040 .
• Determine sign type (wall, monument, window, temporary, electronic) and match to definitions in § 18.152 .
• Prepare sign drawings and specifications; if in a specific plan or larger center prepare a master sign program for design review per § 18.544.240 and Chapter 18.12 (design review) .
• Check illumination and electronic message board standards (auto‑dimming, 0.3 fc limit at 100 ft, fail‑safe) § 18.152.060 .
• Confirm prohibited locations (roof signs, proximity to traffic signals, safety clearances) § 18.152.070 .
• Verify whether an existing sign is nonconforming and review amortization/maintenance rules § 18.152.080 .
• Submit permit application to planning department and building official; expect Chapter 18.12 (design review) if part of a development plan § 18.152.040 .

Risks & Ambiguities

Plain-English Summary

San Dimas requires permits for most signs, controls how big, bright, and where signs can be, treats electronic signs strictly (auto‑dimming and content limits), and often makes developments submit a master sign program and get design review — follow § 18.152 first, then check your zone or specific plan for extra rules (verify with the city) .

Source References

• San Dimas Zoning Code — Sign definitions, compliance and permits: § 18.152.030; § 18.152.040; § 18.152.060; § 18.152.070; § 18.152.080 .
• I‑P Industrial Park sign standards: § 18.508.120(F) (identification and tenant sign area limits) .
• C‑H zone development and sign cross‑reference: § 18.92.050(G) and scenic/setback references § 18.108.050(A) .
• Specific Plan No. 26—master sign program requirement: § 18.544.240 .
• Mobile home park signage requirement and directory sign: mobile home park chapter references to signage and Chapter 18.152 § 18.532.190 .
• Single‑family (Specific Plan No. 5 / Area 2) reference to single family sign rules: § 18.504.360 (calls to Chapter 18.156) .
• Design review and development plan review considerations (sign design as part of total graphic design): Chapter 18.12 findings and review standard references (design review covers signage) § 18.12.060 .
• For state building/electrical construction standards affecting sign construction (structural/electrical permits), consult the California Building Standards Code (Title 24) California Building Standards Code (building‑code review is outside this page’s scope).

Retrieved passages

• San Dimas Zoning Code (§ 1) High relevance show source text
• San Dimas Zoning Code Medium relevance show source text
• San Dimas Zoning Code (§ 1) Medium relevance show source text
• San Dimas Zoning Code (§ 1) Medium relevance show source text
• CBC § 1 (§ 1) Medium relevance show source text
• CBC § 152 Medium relevance show source text
• San Dimas Zoning Code (chapter shall) Medium relevance show source text
• San Dimas Zoning Code (Section 18.152.170) Medium relevance show source text
• CBC § 152 Medium relevance show source text
• San Dimas Zoning Code (§ 1B) Medium relevance show source text
• San Dimas Zoning Code (§ 3) Medium relevance show source text
• San Dimas Zoning Code (section shall) Medium relevance show source text
• San Dimas Zoning Code (§ 18.504.340.) Medium relevance show source text
• San Dimas Zoning Code (§ 1) Medium relevance show source text

Cited sections

• San Dimas Zoning Code — Sign definitions, compliance and permits: **§ 18.152.030; § 18.152.040; § 18.152.060; § 18.152.070; § 18.152.080** . (§ 18.152.030)
• I‑P Industrial Park sign standards: **§ 18.508.120(F)** (identification and tenant sign area limits) . (§ 18.508.120)
• C‑H zone development and sign cross‑reference: **§ 18.92.050(G)** and scenic/setback references **§ 18.108.050(A)** fileciteturn1file9 . (§ 18.92.050)
• Specific Plan No. 26—master sign program requirement: **§ 18.544.240** . (§ 18.544.240)
• Mobile home park signage requirement and directory sign: mobile home park chapter references to signage and Chapter **18.152** **§ 18.532.190** . (chapter references)
• Single‑family (Specific Plan No. 5 / Area 2) reference to single family sign rules: **§ 18.504.360** (calls to Chapter **18.156**) . (§ 18.504.360)
• Design review and development plan review considerations (sign design as part of total graphic design): Chapter **18.12** findings and review standard references (design review covers signage) **§ 18.12.060** . (§ 18.12.060)
• For state building/electrical construction standards affecting sign construction (structural/electrical permits), consult the California Building Standards Code (Title 24) California Building Standards Code (building‑code review is outside this page’s scope). (Title 24)
• SanDimas_ZoningCode.md

• Official San Dimas code library