Local zoning · Sunnyvale

Sunnyvale — Overlay Districts

Q: If I want to build a mixed-use project, what does the MU overlay require?

Mixed-use developments in an MU overlay (applied to R‑3/R‑4/R‑5 ) generally require a special development permit (SDP) and must follow MU siting and design guidance (vertical mixing encouraged, commercial component where required) — § 19.26.220(e–g)

Overlay Districts under the Sunnyvale local zoning and planning code, with the controlling citations.

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Last reviewed: July 2, 2026

Overview

Sunnyvale implements overlay rules as combining districts within the Uniform Planning and Zoning Code (commonly called "Title 19"). Combining districts are overlays that modify, add to, or limit the base zoning rules where special circumstances exist; they do not generally remove base-district obligations unless the combining district expressly says so. See the combining districts general purpose at § 19.26.010 . For how overlays sit with the rest of city planning and zoning, consult Sunnyvale's zoning & planning overview and the city zoning map.

Below is a Sunnyvale-specific, ordinance-grounded reference for the combining/overlay districts established in Chapter 19.26 (the overlay/combining district chapter), plus practical guidance for applicants and property owners.

How to read this page

Bolded district names are the actual Sunnyvale combining-district symbols and names (for example PD, ITR, S).
Every substantive requirement is tied to the controlling code section (shown as § 19.XX.XXX) and the municipal-code file citation.
This page covers only the overlay/combining district rules located in the Sunnyvale Municipal Code; for related site rules see the city's development standards, and for how overlays affect parking see parking. Design-review interactions are discussed with a pointer to design review. For construction questions (Title 24) consult the California Building Standards Code.

District-by-district breakdown (Chapter 19.26)

Note: the combining/overlay districts are codified in Chapter 19.26 of the Sunnyvale code. All cross-references below point to the exact controlling § in that chapter.

PD — Planned Development Combining District

Purpose: Provide a flexible overlay that allows modifications to base zoning for sites with special conditions or where creative/site-specific standards are needed (e.g., irregular lot patterns, significant intersections, or projects needing limited deviations) — § 19.26.020 .
Typical permitted uses: Uses permitted by the underlying district remain allowed; any use that is not listed as permitted in the base district requires an approval before establishment. The PD overlay does not independently add a long list of uses; it modifies how the site can be developed under a permit — § 19.26.030 .
Key approvals/standards: Where the PD is combined with any base district, establishing new uses or constructing/altering structures (beyond what the base zoning already allows) requires either a miscellaneous plan permit (MPP) or a special development permit (SDP) following Chapters 19.82 and 19.90 — § 19.26.030 .
Where it applies: May be combined with any zoning district listed in Chapter 19.16; verify the zoning map and the precise zoning plan to know whether your parcel bears a PD overlay — § 19.26.020 .

O — Office Combining District

Purpose: Permit office uses in residential zones subject to a use permit so that pockets of residential land may allow limited administrative/professional office activity — § 19.26.040 .
Typical permitted uses: Office uses listed in Chapter 19.24 (the O zone use-table) may be allowed but only with a use permit where required — § 19.26.050 .
Dimensional/standards interaction: Dimensional requirements (setbacks, height, lot coverage, minimum lot area) of the underlying residential district continue to apply; floor area ratio (FAR) may apply to residential uses if an FAR exists in the base district — § 19.26.040(c) .
Where it applies: Only where the O symbol is shown on the precise zoning map — verify by map lookup and underlying Chapter 19.24 for office-use definitions.

HH — Heritage Housing Combining District

Purpose: Preserve the character of historic residential neighborhoods designated as heritage-resource districts — § 19.26.060 .
Typical permitted uses: Underlying residential uses remain; the overlay mainly affects demolition and replacement rules rather than introducing new commercial uses.
Key standards: Demolition of residential structures within an HH district requires approval by the heritage preservation commission under Chapter 19.96, with specific findings required before demolition is allowed; replacement structures must be consistent with the district's policy statement — § 19.26.080 .
Where it applies: In residential zones formally designated as heritage-resource districts; check the zoning map and Chapter 19.96 (heritage preservation) for precise boundaries.

ITR — Industrial to Residential Combining District

Purpose: Allow a managed transition of industrial/commercial/office lands to residential uses over time; allow a mixture of industrial, office, commercial and residential uses within the overlay — § 19.26.090 .
Typical permitted uses: When in ITR, industrial/commercial/office uses remain allowed per the commercial/industrial chapters (Chapters 19.20, 19.22, 19.24) and residential uses are allowed in accordance with Chapter 19.18 once approved and shown on the precise zoning plan — §§ 19.26.120–130 .
Key standards and rules:
- Boundaries are shown on the precise zoning map; where boundaries are uncertain, the code gives tie-breaking rules (follow existing lot/streets) — § 19.26.100 .
- If an ITR-site has been "transitioned to residential use" (defined as either completion of foundation/walls or commencement of residential use), the site cannot revert to non-residential uses; the zoning map will be amended to remove the ITR overlay and reflect the residential zone — § 19.26.120 .
- Rebuilding after damage is allowed subject to FAR limits for non-residential buildings (e.g., 35% FAR cap cited for industrial/commercial/office in an ITR unless altered by permit) — § 19.26.110 .
Where it applies: Only in areas shown as ITR on the precise zoning plan/zoning map — confirm via the map.

S — Residential Single-Story Combining District

Purpose: Preserve single-story character in areas overlaying R-0, R-1 and R-2 residential districts; the overlay substitutes its site-development rules for the underlying rules where it applies — § 19.26.200(a)–(b) .
Typical permitted uses: Underlying residential uses remain; the S district is about height and unit configuration, not new commercial uses.
Key dimensional standards (applied in lieu of base rules where S is in effect):
- Maximum height: 17 ft (as defined by the code) — § 19.26.200(f)(1) .
- One habitable floor only (lofts/mezzanines counted; basements excluded) — § 19.26.200(f)(2) .
- Maximum FAR: 45% — § 19.26.200(f)(3) .
Special procedures to create/repeal S: Applications must be initiated by property owners, demonstrate support from at least 55% of property owners in the proposed district, the proposed area must include at least 20 homes, and 75% of homes in the proposed district must be one-story (pre-2005 districts had different expiration rules) — § 19.26.200(d) .
Where it applies: Only where the symbol S appears on the zoning map; existing S districts created before Oct 1, 2005 may have automatic expiration rules (see the code) — § 19.26.200(c)–(e) .

POA — Places of Assembly Combining District

Purpose: Allows certain education, recreation and "place of assembly" uses in M‑S industrial districts that otherwise would not be permitted — § 19.26.210(a–b) .
Noticing and process: For any use-permit application for an educational, recreational or place-of-assembly use in a POA district, the noticing radius is expanded; the applicant must mail notice to 1,000 ft in addition to the normal public-notice requirements — § 19.26.210(c) .
Where it applies: Only where POA appears on the zoning map overlaying M‑S (industrial) zones.

MU — Mixed Use Combining District

Purpose: Encourage coordinated residential + commercial/office projects in higher-density residential zones (R-3, R-4, R-5) near major expressways or transit, and to require commercial/office components where appropriate — § 19.26.220(a–c) .
Typical permitted uses: Mixed-use developments must comply with the MU permit and usually require a special development permit before changing uses or constructing buildings — § 19.26.220(e–f) .
Site-design guidance: Encourages vertical mixed-use (residential over commercial), pedestrian-friendly design, and underground parking where feasible — § 19.26.220(g) .
Where it applies: Only when the MU overlay is adopted by council and shown on the precise zoning map; MU is intended near transit corridors and major roads.

Quick reference table — most decision-relevant standards and permitting triggers

Overlay (Combining District)	Decision-relevant standard / trigger	Code reference
PD	Non-base permitted uses or structural changes require MPP or SDP	§ 19.26.030
O	Office uses in residential zones require a use permit; base residential dimensional rules still apply	§ 19.26.040–050
HH	Demolition requires heritage-preservation commission approval and findings (Chapter 19.96)	§ 19.26.060–080
ITR	Boundaries on zoning map; residential conversion is permanent once transitioned; non-residential FAR limits apply	§ 19.26.100–130
S	Max height 17 ft, one habitable floor, FAR 45%; creation needs 55% owner support, ≥20 homes, ≥75% one-story	§ 19.26.200(d–f)
POA	Expanded public-notice: 1,000 ft mailing radius for certain uses in POA	§ 19.26.210(c)
MU	Mixed-use projects require SDP; commercial component required for certain sites; siting near transit favored	§ 19.26.220(e–g)

Checklist — what an applicant must satisfy (parcel-level verification required)

Confirm whether your parcel has a combining/overlay symbol (PD, O, HH, ITR, S, POA, MU) on the precise zoning plan / zoning map — § 19.16.010 and § 19.26.100 .
Identify the underlying base zoning district and its permitted uses and development rules; overlays generally supplement/defer to the base district — § 19.26.010(b) .
Determine the required discretionary approval: Use Permit, Miscellaneous Plan Permit (MPP), or Special Development Permit (SDP) as specified for the overlay — see § 19.26.030, § 19.26.050, § 19.26.220(e) .
For any new construction or exterior alteration, confirm whether design review is required under Chapter 19.80 and submit accordingly; see design review and § 19.18.030 for triggers — § 19.18.030 .
If your plan affects required parking, consult the city's parking rules and any overlay-specific parking modifications — see parking and Chapters 19.46/19.90 where deviations are authorized — § 19.90.030(a)(8) .
For S district creation or repeal: collect signatures and demonstrate 55% owner support; ensure a proposed district covers at least 20 homes and 75% are one-story — § 19.26.200(d) .
For HH areas, consult heritage preservation procedures in Chapter 19.96 before proposing demolition or substantial alterations — § 19.26.080 .
For ITR sites, if conversion to residential is intended, be prepared to show the physical transition triggers (foundation/walls or commencement of residential use) and that conversion will be permanent — § 19.26.120 .
Always verify whether the overlay expressly modifies setbacks, FAR, height, or lot coverage; where it does, use the overlay standard (e.g., S height and FAR) — § 19.26.200(f) .

Risks & Ambiguities

Issue	Why it matters	What to verify
Whether overlay applies to a particular parcel	Overlays are map-based; misreading the map can cause failure to obtain required permits	Confirm parcel overlay on the city's precise zoning plan / zoning map — § 19.16.010; Verify with Planning staff
Whether combining district reduces base-district requirements	The code generally prohibits reducing base requirements unless expressly stated; misreading could lead to illegal reductions	Check § 19.26.010(b) which says combining districts do not reduce base requirements unless expressly provided; confirm special provisions in the overlay section
S-district petition thresholds and expiration	Older S districts may have different expiration rules — confusing for property-owner petitions	Verify 55% owner support, 20‑home minimum, 75% one-story rule, and expiration/renewal rules in § 19.26.200(d–c)
Subjective demolition findings in HH districts	Heritage findings can be discretionary and fact-heavy; rejection risk is real for demolition plans	Review § 19.26.080 and Chapter 19.96 procedures; get early guidance from Heritage Preservation Commission staff
ITR conversion permanence	Once "transitioned to residential" the site is removed from ITR and cannot revert — this materially affects redevelopment strategy	Confirm the definition of "transitioned to residential" and map amendment process in § 19.26.120
Interactions with design review and site standards	Overlays may change dimensional standards, but design-review thresholds still apply	Check design-review triggers in § 19.18.030 and Chapter 19.80; coordinate with planning staff early

Plain-English Summary

In Sunnyvale, overlays are called combining districts (Chapter 19.26) and they sit on top of the base zoning for parcels shown on the precise zoning map; overlays like PD, ITR, S, MU, O, HH and POA add or change rules (height, FAR, use-permit triggers, noticing, demolition controls) and usually require discretionary permits (use permits, miscellaneous plan permits, or special development permits) before you can change uses or buildings — see the specific code sections cited above for each overlay. Always confirm the overlay on the zoning map and the exact §s that apply for your parcel, and get pre-application advice from the city before you invest in design work.

Source References

Sunnyvale Municipal Code, Chapter 19.26, "Combining Districts" (general purpose and district definitions) — § 19.26.010, § 19.26.020 (PD), § 19.26.030 (permits) . Source downloaded from the city code hosting: https://ecode360.com/SU5020
Office combining district and permits — § 19.26.040–050 .
Heritage housing combining district and demolition review — § 19.26.060–080; Chapter 19.96 (heritage preservation referenced) .
Industrial-to-Residential (ITR) combining district — § 19.26.090–130 (boundaries, transition rules, allowed uses) .
Single-story (S) combining district — § 19.26.200(d–f) (eligibility, petition rules, 17 ft height, one habitable floor, 45% FAR) .
Places of Assembly (POA) combining district — § 19.26.210(c) (expanded 1,000 ft notice) .
Mixed Use (MU) combining district — § 19.26.220 (purpose, SDP requirement, design guidance) .
Design-review triggers and discretionary-permit cross-references — § 19.18.030 and Chapter 19.80 (Design Review) .
Permit procedures and deviation allowances (special development permits, variances) — § 19.90.030, Chapter 19.90 (Special Development Permits) .
Zoning districts list and precise zoning plan references — § 19.16.010–020 .

Sources

Retrieved passages

Sunnyvale Zoning Code (CHAPTER 19.26) High relevance
Sunnyvale Zoning Code (§ 1) High relevance
Sunnyvale Zoning Code (§ 19.24.020.) High relevance
Sunnyvale Zoning Code (§ 19.37.100.) High relevance
Sunnyvale Zoning Code (§ 19.44.160) High relevance
Sunnyvale Zoning Code (§ 19.98.190.) Medium relevance
Sunnyvale Zoning Code (§ 19.22.030) Medium relevance
Sunnyvale Zoning Code (§ 19.36.020.) Medium relevance
Sunnyvale Zoning Code (Chapter 19.16.) High relevance
Sunnyvale Zoning Code (§ 19.26.090.) High relevance
Sunnyvale Zoning Code (§ 1) High relevance
Sunnyvale Zoning Code (§ 19.26.200) High relevance
Sunnyvale Zoning Code (§ 19.30.020) High relevance

Cited sections

Official Sunnyvale code library

Frequently asked questions

What does “combining district” mean in Sunnyvale?

A combining district is Sunnyvale’s term for an overlay that is added to a base zoning designation to address special site conditions or policy goals; combining districts are codified in Chapter 19.26. Overlays typically add permit requirements or substitute limited development standards (for example, S sets height and FAR limits) — § 19.26.010, § 19.26.200

What can I build on a lot that shows the ITR overlay?

Uses follow the ITR rules: industrial/commercial/office uses allowed per Chapters 19.20–19.24, and residential uses are allowed per Chapter 19.18 once the city and map show residential conversion; conversion is permanent once transitioned — see § 19.26.120–130

Do overlays change setbacks and parking requirements?

Sometimes. Most overlays defer to the base district for dimensional standards unless the overlay expressly replaces them (for example, S replaces height/FAR); deviations to parking or setbacks often require discretionary approval such as an SDP — check § 19.26.010(b) and the overlay’s specific § (e.g., § 19.26.200(f) for S) and consult the city’s development standards and parking rules — § 19.26.010

If my lot has the O (office) combining district, do I need a permit to operate an office?

Yes. The O combining district allows office uses where the base residential district otherwise restricts them, but most office uses in an O overlay require a use permit under § 19.26.050; base residential dimensional rules still apply — § 19.26.040–050

How do I create or repeal an S (single-story) combining district?

An S district application must be initiated by property owners and be supported by at least 55% of property owners in the proposed district; the proposed area must include at least 20 homes and 75% of them must be one-story. Repeal also requires similar owner support where specified — § 19.26.200(d–e)

Are demolition controls different in heritage (HH) overlay areas?

Yes. Demolition of residential structures in an HH district requires approval by the heritage preservation commission and specific findings under Chapter 19.96; replacement construction must be consistent with the policy statement for the district — § 19.26.080

Does the POA overlay change public-notice rules?

Yes. For educational, recreational, or place-of-assembly uses in a POA overlay, the noticing radius is expanded: applicants must mail notice to 1,000 ft in addition to the normal public-notice requirements — § 19.26.210(c)

If I want to build a mixed-use project, what does the MU overlay require?

Mixed-use developments in an MU overlay (applied to R‑3/R‑4/R‑5) generally require a special development permit (SDP) and must follow MU siting and design guidance (vertical mixing encouraged, commercial component where required) — § 19.26.220(e–g)

Can combining districts reduce base zoning obligations like minimum lot area?

No — combining districts do not operate to reduce or eliminate base-district requirements or other title requirements except where the combining district expressly provides such a reduction; check § 19.26.010(b) to confirm whether any reduction is expressly allowed — § 19.26.010(b)

Where do I confirm whether my parcel is in a combining district?

Confirm against the city's precise zoning plan / zoning district map on file with the city clerk and consult the Sunnyvale planning counter; the code explicitly ties ITR and other overlay boundaries to the precise zoning map — § 19.16.010 and § 19.26.100

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