Local zoning · Mammoth Lakes

Mammoth Lakes — Historic Preservation

Q: Where in the code does the Town say it wants to preserve historic areas?

The Public and Quasi‑Public (P‑QP) district purpose includes “identify and preserve areas of historic and community significance for the enjoyment of future generations.” § 17.32.090 .

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

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Last reviewed: July 2, 2026

Overview

Mammoth Lakes Title 17 (Zoning) does not establish a standalone historic-preservation chapter; instead, historic considerations are folded into specific zoning rules, design review, and special project standards. Key controls that affect historic resources appear in the Public and Quasi‑Public (P‑QP) district purpose, the Town's design review procedures, and objective rules for urban lot splits / two‑unit projects and ADUs that explicitly exclude or protect historic resources. See the zoning map and district list for where those rules apply.

Notes up front:

Where the code treats “historic” it does so by excluding historic properties or districts from streamlined ministerial processes (e.g., two‑unit projects, urban lot splits).
There is no found local procedure in Title 17 for creating local “landmark” designations or an in‑code historic overlay in the retrieved materials; verify with the Town for separate historic‑preservation ordinances or inventories. Not found in retrieved materials.

Important linked resources referenced below: the Town zoning and planning overview, the local Zoning and Land Use pages; the code’s Development Standards; Design Review; Parking; Overlay Districts; ADUs; and the California Building Standards Code.

How Title 17 treats historic resources (top takeaways)

The Town’s zoning map and district purposes reference preserving “areas of historic and community significance” but do not create a Town historic‑landmark process inside Title 17. See the Public and Quasi‑Public (P‑QP) district purpose. § 17.32.090.
Design review applies to changes to exteriors and therefore is the primary local control that can shape outcomes for historic buildings; design review rules apply generally to exterior work and renovations. § 17.88.010–.020.
The ministerial two‑unit project and urban lot split rules expressly exclude lots that “are a historic property or within a historic district included on the State Historic Resources Inventory” or that “are designated by ordinance as a Town or County landmark.” See § 17.52.260 (urban lot splits / two‑unit projects).
ADUs appear as permitted accessory uses across residential zones and the ADU provisions defer to state law for protection of historic resources; Title 17 references the ADU section and allows objective standards that avoid adverse impacts to listed historic resources. See § 17.52.055 and the ADU provisions.

District‑by‑district breakdown (where historic rules matter)

Note: the Town zoning map and district symbols are adopted in § 17.16.030; use the Zoning Map to verify whether a parcel falls inside the named district.

P‑QP (Public and Quasi‑Public)

Purpose: expressly includes “to identify and preserve areas of historic and community significance for the enjoyment of future generations.” § 17.32.090.
Typical permitted uses: parks, schools, government offices, public assembly uses — see Table 17.32.100 for full use list. P‑QP is tied to institutional/public land‑use designations. § 17.32.090.
Key dimensional / procedural features: uses are set in Table 17.32.100 and many require use permits; design review and other standard development controls (setbacks, parking) apply. § 17.32.090 and Tables.
Where it applies: publicly owned or institutionally used land on the Town Zoning Map; consult § 17.16.030 for the Zoning Map symbols.

Downtown (D)

Purpose: core mixed commercial/residential district centered on Main Street; Town aims to concentrate pedestrian‑oriented development and maintain a “shop‑front” character — these design objectives are relevant when work affects historic façades and street character. § 17.24.010 (Downtown).
Typical permitted uses: ground‑floor commercial, multifamily above, lodging, and active frontages per Table 17.24.020. § 17.24.020.
Key dimensional standards: maximum FAR 2.0 (subject to design, height, snow storage and stepback rules). § 17.24.010.
Where it applies: parcels designated D on the Zoning Map. § 17.16.030.

Old Mammoth Road (OMR)

Purpose: an arts & culture / medium‑scale commercial district oriented to Old Mammoth Road with pedestrian scale; design and façade treatment goals matter for historic resources. § 17.24.010 (OMR).
Typical uses: community retail, galleries, office, some residential/multi‑family per Table 17.24.020. § 17.24.020.
Key dimensional standards: maximum FAR 2.0; design review triggers apply. § 17.24.010–.020.

RSF (Residential Single‑Family) and RR (Rural Residential)

Purpose: RSF for neighborhood single‑family; RR for lower density rural single‑family. § 17.20.010–.020.
Typical permitted uses: single‑family homes, ADUs (Accessory Dwelling Units) as permitted uses (see § 17.52.055). Table 17.20.020 shows ADUs are permitted in RSF and RR.
Key dimensional standards: district development standards/ setbacks/ heights referenced in Table 17.20.030 and Section 17.20.030; two‑unit projects and urban lot splits have special objective standards and historic exclusions in § 17.52.260.
Where it applies: parcels labeled RSF or RR on the Zoning Map. § 17.16.030.

RMF‑2 (Residential Multifamily 2) and MLR (Mixed Lodging/Residential)

Why it matters: denser zones where rehabilitation vs. demolition decisions have bigger housing and policy implications; certain housing conversions and design treatments are subject to use permits and design review. See Table 17.20.020 and § 17.24.020.

PRD (Planned Residential Development) and Resort (R)

These zones require master plans and Commission/Council approvals; design and preservation of character (including historic character) are evaluated as part of the project/master‑plan findings and design review. § 17.32.080 and § 17.32.110.

Most decision‑relevant standards at a glance

Topic	What matters to historic resources	Code reference
Design review applicability	Exterior work, new construction and alterations are generally subject to design review; design review shapes materials, color, massing and landscaping that affect historic character.	§ 17.88.010–.020
Public/Quasi‑Public district purpose	P‑QP explicitly includes preserving areas of historic/community significance — useful when public owners propose changes.	§ 17.32.090
Two‑unit projects / urban lot splits — historic exclusion	Lots that are a historic property, within a State Historic Resources Inventory district, or “designated by ordinance as a Town or County landmark” are excluded from streamlined two‑unit/lot‑split ministerial processing.	§ 17.52.260 (c)(3)(d)
ADUs and historic resources	ADUs are permitted across residential districts; the ADU provisions reference state law protections and allow objective design standards to prevent adverse impacts to resources listed in the California Register. See ADU rules.	§ 17.52.055 and ADU provisions.
Zoning district list (where rules apply)	The Town’s zoning districts (e.g., D, OMR, MLR, RSF, RR, PRD, P‑QP) are adopted in the Zoning Map — consult § 17.16.030 to locate parcels subject to the above rules.	§ 17.16.030

Practical guidance / interpretation (plain‑English synthesis)

If your property is in P‑QP, Downtown (D), OMR, or another district with high design/heritage value, expect design review (Chapter 17.88) to control exterior appearance and site treatments; plan to document historic materials and propose preservation‑sensitive repairs. § 17.88.020.
If you plan an urban lot split or a ministerial two‑unit project, check the “Not historic” exclusion: if the lot is on the State Historic Resources Inventory or is locally designated by ordinance, the ministerial pathway is not available — that will require discretionary review. § 17.52.260(c)(3)(d).
ADUs are allowed on lots with historic buildings, but local objective standards that prevent “adverse impacts” on listed resources can apply; consult the ADU rules and the Director early to confirm what objective standards apply. § 17.52.055.
Where Title 17 is silent (for example, no in‑code local landmark designation procedure was found in the retrieved Title 17 files), ask the Town — there may be a separate historic preservation ordinance, inventory, or design guideline outside of Title 17. Not found in retrieved materials.

Also remember to coordinate with building code requirements for historic structures (California Historical Building Code / Title 24) for life‑safety compliance on alterations; link to Title 24 for code guidance.

Checklist (what an applicant must satisfy for exterior work on a potentially historic property)

Confirm zoning district and whether parcel is on the Town Zoning Map (§ 17.16.030).
Verify whether the property is listed on the State Historic Resources Inventory or is designated by any local/county ordinance (if listed, ministerial two‑unit/lot‑split routes are not available) § 17.52.260(c)(3)(d).
Determine whether the project is subject to design review (exterior work normally is) and prepare materials/photographs, design drawings and a materials palette for Commission/Director review § 17.88.010–.020.
For ADUs, follow § 17.52.055 objective ADU standards and identify any provisions preventing adverse impacts to listed resources § 17.52.055.
If pursuing an urban lot split or two‑unit project, assemble required forms, deed restrictions and affidavits and confirm the parcel is not excluded by the “Not historic” rule § 17.52.260.
Prepare any zoning‑required studies (e.g., site plan, landscaping, parking plan) and follow relevant development standards and parking rules.

Risks & Ambiguities

Issue	Why it matters	What to verify
No dedicated local “historic preservation” chapter found	If the Town has a separate landmark designation ordinance or inventory, it may sit outside Title 17; missing it changes entitlement route and noticing.	Confirm with the Town whether a separate historic‑preservation ordinance, list, or commission exists. Not found in retrieved materials.
“Not historic” exclusion for ministerial projects	Being listed on the State inventory or as a local landmark removes access to streamlined ministerial approvals (two‑unit/urban lot split). § 17.52.260	Verify whether the parcel appears on the State Historic Resources Inventory and whether the Town has a local designation by ordinance.
Design review threshold ambiguity	Design review applies broadly to exterior work but exemptions exist (e.g., small additions, routine maintenance). Mis‑classification can delay approvals. § 17.88.020	Confirm with the Director whether the proposed scope triggers design review; review design‑review exemptions.
ADU objective standards vs. historic protections	State ADU law and local ADU rules both apply; local objective rules must not unreasonably restrict ADUs but may prevent adverse impacts to registered historic resources.	Ask the Planning Director how objective ADU standards will be applied to the specific historic resource; consult the ADU section § 17.52.055.
Parcel‑specific constraints (e.g., flood, fault, fire)	Separate site hazards can preclude ministerial lot splits or trigger discretionary review even absent historic issues. § 17.52.260(c)	Check FEMA maps, state fault maps, and MLFPD fire zone designations early.

Plain‑English summary

Mammoth Lakes does not have a discrete historic‑preservation chapter inside Title 17; instead, historic resources are protected through the Public and Quasi‑Public district purpose, the Town’s design review rules, and explicit exclusions from ministerial housing/lot split pathways — if a property is on the State inventory or locally designated as historic, streamlined two‑unit and urban‑lot‑split approvals are not available and you should expect discretionary review.

Source References

Title 17 — ZONING (Town print export). See Title, applicability and administration. § 17.04.001–.060.
Zoning Districts table and map (district symbols including D, OMR, MLR, RSF, RR, PRD, P‑QP). § 17.16.030.
Residential uses and ADU cross‑references: Table 17.20.020 and § 17.20.030 (development standards).
Commercial district descriptions (Downtown, Old Mammoth Road, MLR). § 17.24.010, Table 17.24.020.
Public & Quasi‑Public zone purpose (historic preservation language). § 17.32.090.
Urban lot splits / two‑unit projects (objective ministerial rules and the “Not historic” exclusion). § 17.52.260 (see c. and d.).
Design review chapter (applicability and exemptions). § 17.88.010–.020.
ADU rules referenced in use tables and state‑law conformity (see Table 17.20.020, § 17.52.055).
California Historical Building Code and related historic building references (State code guidance referenced in local review contexts). Noted in State codes included in the materials.

Sources

Retrieved passages

Mammoth Lakes Zoning Code High relevance
CBC § 65913.4 (§ 65913.4) High relevance
Mammoth Lakes Zoning Code (Section 17.48.090) High relevance
Mammoth Lakes Zoning Code (§ 17.96.020) High relevance
CBC § 7060 (§ 7060) Medium relevance
Mammoth Lakes Zoning Code (Chapter 3.12.) Medium relevance
Mammoth Lakes Zoning Code (§ 65915) Medium relevance
Mammoth Lakes Zoning Code Medium relevance
Mammoth Lakes Zoning Code (§ 17.04.040) Medium relevance
Mammoth Lakes Zoning Code (§ 17.84.050) Medium relevance
Mammoth Lakes Zoning Code (§ 17.36.090) Medium relevance
CBC § 65913.4 (§ 65913.4) Medium relevance
Mammoth Lakes Zoning Code Medium relevance
CBC § 18955 (Section 18955) Medium relevance
Mammoth Lakes Zoning Code (§ 65589.5) Medium relevance
Mammoth Lakes Zoning Code (title individually) Medium relevance
Mammoth Lakes Zoning Code (§ 65589.5) Medium relevance
Mammoth Lakes Zoning Code (Chapter 17.116.) Medium relevance
Mammoth Lakes Zoning Code (Chapter 17.60) Medium relevance
CFC § 66427.4 (§ 66427.4.) Medium relevance
CBC § G106 (SECTION G106) Medium relevance
CBC § 2025 Medium relevance
Mammoth Lakes Zoning Code (Title 17) Medium relevance
Mammoth Lakes Zoning Code (chapter or) Medium relevance
Mammoth Lakes Zoning Code Medium relevance
Mammoth Lakes Zoning Code (chapter is) Medium relevance
Mammoth Lakes Zoning Code (§ 17.20.030) Medium relevance
Mammoth Lakes Zoning Code (§ 17.20.010) Medium relevance
Mammoth Lakes Zoning Code (Chapter 17.56) Medium relevance

Cited sections

Official Mammoth Lakes code library

Frequently asked questions

What does Mammoth Lakes code say about design review for historic buildings?

Design review is the primary local process for exterior changes: Title 17 requires design review for new construction, reconstruction, rehabilitation, alteration, or improvements to exteriors unless a specific exemption applies; that review is where preservation‑sensitive materials, massing and façade treatments are decided. § 17.88.010–.020.

Can I build an ADU on a historic property in Mammoth Lakes?

Yes — ADUs are permitted in the residential zones, and Title 17 references ADU provisions while allowing objective design standards that prevent adverse impacts to historic resources; consult the ADU rules and the Director early for objective standards that will apply. § 17.52.055.

Does the Town have a local landmark designation with legal protections in Title 17?

No dedicated local landmark designation process or historic‑preservation chapter was found in the retrieved Title 17 materials; Title 17 references historic resources in places (e.g., exclusions from ministerial routes), but a separate local ordinance or inventory may exist outside Title 17 — verify with the Town. Not found in retrieved materials.

Will an urban lot split or two‑unit project be blocked by a local historic listing?

Yes — Title 17 expressly excludes parcels that “are a historic property or within a historic district that is included on the State Historic Resources Inventory” or that are “designated by ordinance as a Town or County landmark” from ministerial urban lot split / two‑unit project processing. § 17.52.260(c)(3)(d).

Where in the code does the Town say it wants to preserve historic areas?

The Public and Quasi‑Public (P‑QP) district purpose includes “identify and preserve areas of historic and community significance for the enjoyment of future generations.” § 17.32.090.

If I own a building in Downtown (D), what historic‑related controls should I expect?

Downtown (D) is a pedestrian‑oriented, shop‑front district with a design emphasis; exterior alterations will generally be evaluated through design review and must meet Downtown development standards (including FAR, stepbacks, frontage rules) set out in § 17.24.010–.020 and Chapter 17.88.

Do two‑unit projects have height, setback, or demolition limits if a structure is historic?

Two‑unit and urban‑lot rules set objective limits (e.g., maximum height for new primary units 24 feet, minimum separation and setback rules, and a 25% demolition cap for exterior walls in some cases); but if the lot is historic (per State inventory or local designation) the streamlined ministerial path is not available — discretionary review will control. § 17.52.260.

Who makes design and landmark decisions in Mammoth Lakes?

Title 17 assigns administration to the Town Council, the Planning and Economic Development Commission, and the Community and Economic Development Director; design review decisions are handled under Chapter 17.88 with Director or Commission roles defined in Chapter 17.92. § 17.04.050, § 17.88, § 17.92.

If my property is listed on the State Historic Resources Inventory, can I get a ministerial two‑unit approval?

No — the code specifically says a lot that is a historic property or within a State‑listed historic district is excluded from the ministerial two‑unit / urban lot split process. Expect discretionary review instead. § 17.52.260(c)(3)(d).

What should I do first if I own a potentially historic building and want to renovate?

First, confirm zoning and whether the parcel appears on any historic lists; then meet with the Community & Economic Development Director to determine whether your project triggers design review and whether ministerial routes (e.g., ADU, two‑unit) are available — early pre‑application consultation is strongly advised. § 17.16.030, § 17.88, § 17.52.260. ---

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