Local zoning · Walnut

Walnut — Historic Preservation

Historic Preservation under the Walnut local zoning and planning code, with the controlling citations.

Last reviewed: July 3, 2026

Overview

Walnut’s historic preservation rules are codified in Chapter 6.104 — Historical Preservation of the Walnut Municipal Code; the chapter establishes designation criteria, a Historic Resources Register, a review process and incentives for owners of designated resources (see § 6.104.010–§ 6.104.140) . Exterior changes to designated resources require site plan and architectural review under the City’s planning rules and objective standards; see the City’s design review process and the broader development standards that apply to each zone (§ 6.104.080) . The Historical Preservation program is administered by a historical preservation ad‑hoc advisory committee appointed by the City Council (§ 6.104.040–§ 6.104.050) .

How the Historic Preservation Chapter works, district‑by‑district

Note: Chapter 6.104 applies to designated historical resources citywide; the following district entries show the local zone names used in Walnut and the chapters that set base uses and development rules that will interact with historic‑resource reviews. For exact permit standards consult the cited § and verify with staff for parcel‑specific rulings.

R-1 (One‑Family Residential)

Purpose: Provide for one‑family dwellings and limited accessory/agricultural uses (see § 6.12.010) .
Typical permitted uses: one‑family dwelling, limited agriculture, home day care and accessory buildings — see § 6.12.020 and § 6.12.030 for accessory use rules and guest‑house provisions .
Where historic rules bind: Any designated historic house in R‑1 is subject to the Chapter 6.104 plan review requirement for exterior changes (§ 6.104.080) and must be listed in the Historical Resources Register (§ 6.104.090) before incentives are available .
Key dimensional standards: Base zoning rules and yard/height provisions are in Chapter 6.12 and Chapter 6.08 (Yard/height rules; see § 6.12.010 and general yard rules in § 6.08.080) — plan reviewers will check compatibility of any addition with these standards as part of historic plan review .

R-2 (Limited Multiple‑Family Residential)

Purpose & permitted uses: Intended for two‑family and limited multi‑family uses; see § 6.28.010 and § 6.28.020 for intent and permitted uses .
How historic rules apply: Exterior alterations to an identified historic resource in an R‑2 zone require the Chapter 6.104 site plan and architectural review and recommendation by the historical preservation ad‑hoc advisory committee (§ 6.104.080; § 6.104.050) .
Key dimensional standards: Lot coverage limits and yard requirements are in Chapter 6.28 (e.g., § 6.28.080 sets maximum lot coverage for R‑2) and will be evaluated for compatibility in the historic plan review stage .

R-3 (Multiple‑Family Residential)

Purpose & uses: For apartments/multiple dwellings — see § 6.32.010 and § 6.32.020 for intent and permitted uses .
Dimensional standards relevant to preservation: The R‑3 maximum height and floor area rules used as compatibility benchmarks appear in § 6.32.050 (maximum building or structural height: two stories or 35 feet for main buildings) and yard rules in § 6.32.060; these are referenced during Chapter 6.104 plan review when resources are within R‑3 areas .

RPD (Residential Planned Development)

Purpose: RPD allows planned projects with tailored design guidelines; the City specifically requires preservation of natural and landmark features in RPD review guidelines (§ 6.24.040) .
Historic interplay: Because RPD projects are reviewed under precise plans and conditional use permits, the historical preservation committee will advise on nominations and any alteration that affects designated resources and will recommend conditions to the Planning Commission or City Council (§ 6.104.050; § 6.104.070) .

MU/HOO (Mixed‑Use / Housing Opportunity Overlay Zones)

Purpose and where it applies: MU/HOO zones are overlaid on base zones to encourage higher density/mixed‑use; see § 6.20.010–§ 6.20.020 for purpose and mapped areas .
Historic rules: New construction or land‑use changes in MU/HOO that affect a designated historical resource must go through site plan and architectural review; the review will evaluate compatibility with the resource under § 6.104.080 and the overlay’s specific plan standards (§ 6.20.050–§ 6.20.070) .

(Remember: Chapter 6.104 applies to designated resources citywide — check the Historical Resources Register to confirm designation status before planning work, per § 6.104.090) .

Quick reference table — most decision‑relevant historic‑preservation rules

Topic / standard	What it means in practice	Code Reference
What qualifies as a historic resource	Uses National/State criteria or local criteria (elements of city history, association with significant persons/events, architectural significance, etc.) — the committee uses these in nominations	§ 6.104.060
How to nominate or remove a resource	Anyone (with owner consent) can submit a nomination or removal request to Community Development; review by the committee and public hearing before City Council	§ 6.104.070
Plan review required for alterations	Exterior work (restoration, rehab, additions, demolition, relocation) requires site plan & architectural review and committee recommendation	§ 6.104.080
Historical Resources Register	Designated resources are kept on a register maintained by the advisory committee; copy on file with City Clerk	§ 6.104.090
Preservation incentives	City may use SHBC, façade easements, fee reductions, awards, Mills Act contracts and other incentives (subject to Council approval)	§ 6.104.100
Maintenance & repair	Owners must keep designated resources in good repair; ordinary maintenance allowed, but changes that alter design trigger review; public‑safety removals must be certified	§ 6.104.120
Enforcement & remedies	Unauthorized demolition/alteration can require restoration to the pre‑violation appearance; civil/criminal penalties also possible	§ 6.104.130
Recordation for incentives	To qualify for incentives, owners must record a disclosure instrument about the designation	§ 6.104.140

Practical guidance / synthesis

Designation is a local process that uses national/state criteria but is implemented locally: prepare nomination material that maps the resource, documents historic significance against § 6.104.060 criteria and secures the owner’s consent before filing (see § 6.104.070) .
Once a property is nominated or designated, no ministerial or discretionary permit that would affect the resource may be issued while the designation/removal is pending (§ 6.104.070(D)) — plan early and expect a pause while the City conducts its review .
All exterior alterations are judged for compatibility with the resource’s character — reviewers will consider style, materials, proportions and setting under § 6.104.080; therefore submit elevations, material samples and a written compatibility statement with applications .
The City supports financial incentives (including pursuit of Mills Act contracts) but these require Council review and separate approvals — don’t assume tax relief is automatic; follow § 6.104.100 for possible incentives and § 6.104.140 for recordation requirements to qualify .
Because plan review for historic resources is handled via the City’s site plan/architectural review, you’ll interact with the same application channels used for design review and will need to follow the City’s objective standards for the underlying zone and any overlay districts that apply; parking and other development concessions may be governed separately (see parking and overlay rules) .

Additional practical note: the Chapter explicitly references use of the State Historic Building Code (SHBC) as a preservation incentive and as a way to address public‑safety alterations; consult the California Building Standards Code and the City Building Division early for code/permit coordination (§ 6.104.100(A)) .

Checklist

Confirm whether the property is already listed on the Historical Resources Register (§ 6.104.090)
If designating: prepare a written nomination with owner consent and documentation against criteria in § 6.104.060 and submit to Community Development (§ 6.104.070(A))
If proposing exterior work: prepare site plans, elevations, materials, and a compatibility analysis for the Chapter 6.104 plan review (§ 6.104.080)
Expect review by the historical preservation ad‑hoc advisory committee and a City Council public hearing for designations/removals (§ 6.104.040; § 6.104.070(C))
If seeking incentives (fee reductions, Mills Act, SHBC use), prepare any required recordation instruments and Council authorization per § 6.104.100 and § 6.104.140
Understand appeals timeline and process (appeals per § 6.104.110 and the broader appeals procedures in § 6.80.170)

Risks & Ambiguities

Issue	Why it matters	What to verify
Is the structure already designated?	Designated status triggers plan review, recordation obligations and possible restrictions/incentives.	Check the City’s Historical Resources Register on file with the City Clerk (Historical Resources Register) and confirm with Community Development (§ 6.104.090)
Scope of "alteration" that triggers review	Minor maintenance is allowed, but alterations that change design/materials trigger plan review and committee recommendation (§ 6.104.120; § 6.104.080)	Verify with the Community Development Director whether proposed work is "ordinary maintenance" or requires plan review (see § 6.104.120)
Mills Act / tax incentive eligibility	Mills Act requires Council approval and has legal/recordation consequences (§ 6.104.100(F))	Confirm eligibility, required preservation covenants, and recordation steps with City Clerk and City Attorney; verify local Mills Act policy
Relationship between SHBC and local permits	SHBC can alter building‑code paths for historic rehabilitation but does not replace local planning review (§ 6.104.100(A))	Coordinate with Building Division on use of SHBC and confirm which inspections/plan checks remain under Title 24/City jurisdiction; see California Building Standards Code
ADUs and designated properties	The historical chapter does not expressly state special ADU rules for designated resources.	Not found in retrieved materials — Verify ADU compatibility and required historic review with Community Development and review ADU rules as applicable.
Parcel‑specific conflicts between overlay rules and preservation	Overlays (MU/HOO, Specific Plans) may allow deviations; their standards may conflict or require reconciliation with historic‑resource compatibility review	Verify which overlay or specific plan applies to the parcel (see overlay districts) and ask staff whether specific plan standards or Chapter 6.104 controls; see § 6.20.050 and § 6.104.080

Plain‑English summary

Walnut’s local code (Chapter 6.104) creates a local historic‑resource register, says how buildings/sites are nominated and removed, requires that most exterior work on designated resources get architectural/site‑plan review with input from an ad‑hoc preservation committee, and offers incentives (like Mills Act and use of the State Historic Building Code) subject to Council approval; read § 6.104.060–§ 6.104.140 and check the register before starting work .

Source References

Walnut Municipal Code — Chapter 6.104, Historical Preservation: § 6.104.010 (intent/purpose) through § 6.104.140 (recordation) .
Nomination and plan‑review procedures: § 6.104.070 (designation/removal procedures) and § 6.104.080 (plan review) .
Criteria for designation: § 6.104.060 (National/State/local criteria) .
Incentives and Mills Act reference: § 6.104.100 (preservation incentives, including SHBC and Mills Act) .
Maintenance, enforcement and recordation: § 6.104.120; § 6.104.130; § 6.104.140 .
Zoning chapters referenced for district context: § 6.12.010–§ 6.12.030 (R‑1); § 6.28.010–§ 6.28.080 (R‑2); § 6.32.010–§ 6.32.060 (R‑3); § 6.24.040 (RPD guidelines); § 6.20.010–§ 6.20.070 (MU/HOO overlay) .
Appeals procedure cross‑reference: § 6.104.110 referencing § 6.80.170 (Appeals) .
For building‑code coordination and the SHBC incentive, consult the California Building Standards Code and coordinate with the City Building Division (§ 6.104.100(A)) .
City register and inventory note: Historical Resources Register kept on file with the City Clerk; committee maintains inventory (§ 6.104.090) .

Sources

Retrieved passages

CBC § 6.104.090 (§ 6.104.090.) High relevance
Walnut Zoning Code (§ 6.104.030.) High relevance
Walnut Zoning Code (§ 6.104.070.) High relevance
Walnut Zoning Code (§ 6.104.060.) High relevance
Walnut Zoning Code (§ 6.100.140.) High relevance
Walnut Zoning Code (§ 6.104.020.) High relevance
Walnut Zoning Code (§ 6.100.120.) Medium relevance
Walnut Zoning Code (article may) Medium relevance
Walnut Zoning Code (§ 6.24.040.) Medium relevance
Walnut Zoning Code Medium relevance
Walnut Zoning Code (Chapter 6.08.) Medium relevance
Walnut Zoning Code (§ 6.32.040.) Medium relevance
Walnut Zoning Code (§ 6.20.040.) Medium relevance
Walnut Zoning Code Medium relevance
Walnut Zoning Code Medium relevance
Walnut Zoning Code Medium relevance

Cited sections

Official Walnut code library

Frequently asked questions

What criteria does Walnut use to decide if a building is historic?

Walnut’s advisory committee recommends designations using National Register and California Register criteria and local criteria in § 6.104.060 (e.g., association with events/people, architectural significance, unique location) — the committee’s findings guide City Council action on nominations (§ 6.104.060; § 6.104.070) .

How do I nominate my house for the Walnut Historical Resources Register?

Submit a written nomination with the owner’s consent and supporting documentation to the Community Development Department; the historical preservation ad‑hoc advisory committee reviews and recommends to the City Council, which holds the public hearing per § 6.104.070 .

If my building is listed, what permits require extra review?

Exterior alterations (restoration, rehab, additions, demolition, relocation, subdivision) of a designated historic resource require site plan and architectural review under § 6.104.080, including committee recommendation and City Council consideration when applicable .

Can I use the State Historic Building Code for a rehabilitation project in Walnut?

Yes — the City explicitly lists the State Historic Building Code (SHBC) as an incentive/alternative compliance path for rehabilitation of historic structures in § 6.104.100(A); coordinate early with the City Building Division and Community Development .

Are there tax incentives or property‑tax contracts for historic properties?

Walnut may support Mills Act/historic preservation contracts and other incentives, but they require review and approval by the City Council per § 6.104.100(F); owners must record required instruments to qualify as noted in § 6.104.140 .

What happens if someone illegally demolishes a designated historic resource?

The City can require restoration to the pre‑violation appearance and pursue civil and criminal remedies; enforcement and restoration obligations are set out in § 6.104.130 .

Do historic‑resource rules change setback or parking requirements?

Historic plan review evaluates compatibility with the resource, but the base zone’s setback, lot coverage and parking rules still apply; reviewers will consider those standards during review (refer to the applicable zoning chapter and § 6.104.080). Check the City’s parking rules and your zone’s development standards early; specifics depend on zone/overlay and project scope .

If a property is being considered for designation, can I get permits while that is pending?

No. No ministerial or discretionary permit that may affect a resource under consideration may be issued while designation or removal is pending (§ 6.104.070(D)) — plan accordingly and file early to avoid delays .

Will adding an ADU to my historic house be treated differently?

The historical chapter does not specify separate ADU rules for designated properties in the retrieved materials. Verify with Community Development whether an ADU proposal on a designated resource must meet additional historic compatibility conditions beyond general ADU standards; see ADUs and Chapter 6.104 for review triggers (Not found in retrieved materials for special ADU rules) .

Who makes the final decision on designations and major changes to historic resources?

The historical preservation ad‑hoc advisory committee advises and recommends, but the City Council makes the final decision on designation/removal following the hearing procedures in § 6.104.070(C); appeals follow the appeal provisions cited in § 6.104.110 and § 6.80.170 .

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