Local zoning · Solano County

Solano County — Overlay Districts

Q: What is a Policy Plan Overlay (PP) in Solano County and when is it used?

A Policy Plan Overlay (PP) is a County overlay used to create parcel‑ or project‑specific zoning rules for large or mixed‑use developments; it combines zoning, master/precise plan functions, design standards and infrastructure planning in one process. A PP is added to the zoning map with the suffix “-PP” and is adopted only after the Board makes the findings listed in § 28.68(d) .

Q: What can I build on land inside the Travis Reserve Area (TRA) overlay?

Within the TRA , agrarian activities like crop production and grazing are allowed, and agricultural accessory structures under 2,500 ft² and 25 ft high are permitted; no new residential uses are allowed and other non‑agricultural uses generally require a Minor Use Permit or Use Permit. See § 28.65(B) .

Q: How do I know if my parcel is in an overlay (TRA or -PP)?

The County’s official zoning map shows overlays: a PP appears as the base district plus “-PP” and a serial number referencing the rezoning petition file; TRA is mapped as the Travis Reserve Area overlay. The ordinance requires checking the official map and rezoning petition file to see exact boundaries — verify with the County’s planning/GIS staff . See § 28.68(b) .

Q: Will a Policy Plan Overlay change setback, height, or parking rules?

Yes — a PP is expressly intended to set project‑specific height, building coverage, yard setbacks , and other development standards as part of the required development plan. Applicants must include these standards in their PP application per § 28.68(c) and should refer to the County’s Development Standards and Parking rules when preparing maps and calculations. /us/california/solano-county/development-standards /us/california/solano-county/parking

Q: If my property is within a PP application under review, can I start new uses?

No — during PP review the ordinance limits property uses to those that were permitted under the zoning in effect at the time the PP application was filed (the “interim applicable zoning” rule). See § 28.68(e) .

Q: Are accessory residential units (ADUs) allowed inside the TRA?

The TRA states “No new residential uses are permitted.” Because ADUs are a form of residential development, ADU treatment inside the TRA is not clearly authorized by the overlay text in the materials retrieved; applicants should verify with the County and reconcile the overlay language with state ADU law. /us/california/california-adu-laws

Q: Who approves PP overlays and what findings must the Board make?

A PP overlay is adopted by the Planning Commission and the Board of Supervisors by ordinance; the Board must find the PP is consistent with the General Plan, produces a stable and desirable character, meets development requirements and provides adequate mitigation for adverse impacts — see § 28.68(d) for the required findings.

Q: Can the Director of Resource Management change an approved PP?

The Director may approve minor design, site, sign, and building alterations that are substantially in accord with an approved PP, provided the request is submitted in writing and explains why the change still conforms with the approved PP; see § 28.68(f) . For anything beyond minor alterations, a formal amendment is required.

Q: How are conflicts between overlay regulations and other County code sections resolved?

Where a conflict occurs between an overlay’s regulations and other provisions of the Zoning Ordinance, the overlay regulations specified in the PP chapter will prevail for development and uses within the overlay where the overlay expressly prescribes contrary regulations. See § 28.68(g) .

Q: Who enforces the TRA restriction on new residential uses?

The County enforces overlay rules through the permit/entitlement process; applicants seeking to construct or change uses in the TRA must obtain permits consistent with § 28.65 , and existing nonconforming residences are handled under the County’s nonconforming rules ( § 28.114 ). Contact the Department of Resource Management for parcel‑specific enforcement guidance.

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

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Last reviewed: July 3, 2026

Overview

This page explains the overlay districts that apply in the unincorporated areas of Solano County under the County Zoning Ordinance (Chapter 28). For a high‑level primer on County land use programs see the Solano County zoning & planning overview. Overlay districts in Solano County are special zoning tools that sit on top of a base district to add area‑specific restrictions, flexibility, or an alternative development procedure; the ordinance’s primary overlay provisions are the Travis Reserve Area (TRA) Zoning Overlay and the Policy Plan Overlay (PP). The rules and process language below are drawn from the County Zoning Ordinance (Chapter 28) and are applicable only to unincorporated areas. See the Code citations after each point for verification.

What the ordinance actually establishes about overlays (summary of controlling sections)

The County collects overlay and special‑district rules under Chapter 28, Article VI — Special and Overlay Districts (see § 28.60 and following) of the Solano County Zoning Ordinance.
The ordinance identifies specific overlay/special districts by name: Park (P) (special district), Travis Reserve Area (TRA) Zoning Overlay, and Policy Plan Overlay (PP) Districts. The TRA and PP are the main overlays used to control land use outcomes in targeted areas.
Policy Plan Overlay (PP) districts require a written development plan and are shown on the official zoning map with the suffix “-PP” added to the base district; the ordinance lists the minimum application contents, the required findings for approval, interim zoning rules during review, and administrative/modification processes (§ 28.68).
Travis Reserve Area (TRA) Zoning Overlay is a named overlay implementing the General Plan’s Travis Reserve Area; it limits new residential uses, preserves agricultural uses, and requires discretionary review for most non‑agricultural changes (§ 28.65).

(Throughout the rest of this page every district name and numeric standard is in bold. For the County’s baseline dimensional rules that an overlay may alter, consult the County’s Development Standards.)

Policy Plan Overlay (PP) — § 28.68

Purpose

The Policy Plan Overlay (PP) is intended to encourage comprehensive, large‑scale or mixed‑use planning and to allow parcel‑ or project‑specific standards and land use allocations that may differ from the underlying base district where consistent with the General Plan. § 28.68(a) sets this purpose.

Where it applies / map ID

The overlay may be combined with any General Plan area or zoning district. Each adopted PP district is shown on the official zoning map by adding the suffix “-PP” to the base district and a serial number referencing the rezoning petition file. § 28.68(b).

What must an application contain (selected highlights)

The ordinance requires a development plan and a written statement of standards that at minimum include: statement of purpose; permitted, accessory, conditional and prohibited uses; architectural and sign standards; height, building coverage and yard setbacks; landscaping; parking and loading; additional development and performance standards; and site‑specific policies. A fee, legal description, narrative of existing uses, and findings of General Plan consistency are also required. See § 28.68(c) for the full list.

Decision criteria / required findings

The Board of Supervisors may only adopt a PP overlay after making findings that the proposal: (1) is consistent with the General Plan and any applicable specific plan; (2) produces a stable and desirable character consistent with applicable goals; (3) meets development requirements and shows creativity/innovation; and (4) provides adequate mitigation of objectionable or hazardous impacts. These findings are listed in § 28.68(d).

Interim zoning and administration

While a PP overlay application is under review, uses on the subject property are limited to those allowed under the zoning that existed at the time the application was filed (interim applicable zoning). § 28.68(e). The Director of Resource Management is authorized to approve building construction and minor design/site alterations if they are substantially in accord with an approved PP; minor alterations must be requested in writing and explained. § 28.68(f). Conflicts between overlay regulations and other code provisions are resolved in favor of the overlay where the overlay specifically prescribes contrary regulations. § 28.68(g).

Practical guidance

Expect site‑specific dimensional standards and a package that bundles zoning, design review, and capital improvements (the PP functions like a combined master/precise plan). For required application content and the findings checklist, follow the items listed in § 28.68(c)–(d) and consult the County’s Development Standards, parking rules, and design review procedures when preparing detailed drawings. For parking specifics see the County’s Parking guidance. See also the County’s Design Review page for architectural approval expectations. /us/california/solano-county/development-standards /us/california/solano-county/parking /us/california/solano-county/design-review

Travis Reserve Area (TRA) Zoning Overlay — § 28.65

Purpose

The Travis Reserve Area (TRA) Zoning Overlay "implements the Travis Reserve Area, as described and shown in the General Plan," protecting land for continued crop production and grazing and restricting new development until a military use or other use supporting Travis Air Force Base is proposed. § 28.65(A).

Typical permitted uses and permit requirements (selected)

Allowed by right: crop production, grazing, and agricultural accessory structures that are less than 2,500 square feet gross floor area and less than 25 feet in height. § 28.65(B).
Prohibited/new restrictions: No new residential uses are permitted in the TRA; existing legal nonconforming residential uses are governed by the County’s nonconforming‑uses rules (see § 28.114) and special handling applies. § 28.65(B).
Other uses allowed in the underlying base zoning are generally subject to a Minor Use Permit prior to development, enlargement, intensification, or change of use, unless the use requires a Use Permit. § 28.65(B).

Where it applies / practical effect

The overlay implements General Plan policy to reserve certain lands near Travis AFB — landowners within the overlay should assume limited development rights for new housing and stronger discretionary review for non‑ag uses. Confirm whether a parcel is mapped in the TRA on the official zoning map. Verify parcel status with the County. For questions about whether an accessory dwelling or ADU is allowed, note the TRA’s explicit bar on new residential uses and consult California ADU law and County ADU practice—however, the overlay text itself states “No new residential uses are permitted”, so ADU eligibility is unclear without County verification; Verify with the jurisdiction. /us/california/california-adu-laws

Comparison table — decision‑relevant overlay rules

Topic	Travis Reserve Area (TRA)	Policy Plan Overlay (PP)	Code Reference
Primary purpose	Protect land for crop/grazing and reserve for possible Travis AFB‑related uses	Allow comprehensive, project‑specific zoning and standards for large/mixed developments	§ 28.65; § 28.68
New residential	Not permitted (existing legal nonconforming residences governed by § 28.114)	Site‑specific — PP may allow/modify residential depending on findings	§ 28.65(B); § 28.68(d)
Allowed agricultural uses	Crop production, grazing, accessory structures < 2,500 ft² & < 25 ft	PP can set its own permitted uses and accessory standards per application	§ 28.65(B); § 28.68(c)(6)
Review level for non‑ag uses	Minor Use Permit or Use Permit (as required)	Adoption by Planning Commission and Board via ordinance after required findings; detailed development plan required	§ 28.65(B); § 28.68(d)
Interim zoning during review	N/A (TRA is an adopted overlay)	During PP review only uses allowed under existing zoning at time of application may proceed (interim applicable zoning)	§ 28.68(e)
Administrative modification	N/A (discretionary for permits)	Director may approve minor alterations substantially in accord with the approved PP; formal process described in § 28.68(f)	§ 28.68(f)

Checklist — what an applicant must satisfy (PP or TRA context)

Confirm parcel is in an overlay by checking the official Solano County zoning map and the County’s zoning files (verify TRA or any -PP designation). Verify with the jurisdiction.
For PP: Prepare a development plan and written standards that include: statement of purpose; permitted/accessory/conditional/prohibited uses; architectural/sign standards; height, building coverage, and yard setbacks; landscaping; parking and loading; performance standards; and site‑specific policies per § 28.68(c). Consult the County’s Development Standards and Parking requirements for technical dimensions. /us/california/solano-county/development-standards /us/california/solano-county/parking
For TRA: Demonstrate the project conforms to TRA limits — no new residential uses; agricultural accessory buildings under 2,500 ft² and 25 ft are permitted; other base‑zone uses need a Minor Use Permit or Use Permit as required. § 28.65(B).
Pay applicable fees and provide legal description and narrative of existing/adjoining uses. § 28.68(c)(1–3).
Prepare representative design details: building elevations, streetscape, grading/drainage/utility plans, schedule of improvements and funding strategy (PP minimum requirements). § 28.68(c)(6–m).
For projects requiring architectural approval or design review, follow the County’s design review procedures and be prepared for conditions requiring revisions. /us/california/solano-county/design-review

Risks & Ambiguities

Issue	Why it matters	What to verify
Site‑specific PP standards	The PP is expressly intended to create unique standards for the subject area — you cannot assume standard base‑zone setbacks or uses will apply.	Confirm the adopted PP language and map for the parcel. See § 28.68(c) and § 28.68(b).
TRA and residential prohibition	The TRA text bars new residential uses, which may block ADUs or other housing unless an exemption applies.	Verify whether an ADU or ministerial residential entitlement is treated as a “new residential use” under the overlay; consult County staff and the nonconforming uses rules § 28.114. Verify with the jurisdiction.
Interim zoning during PP review	Uses permitted at application time are protected during review; applicants may be constrained if they wait to apply.	Confirm the baseline zoning in effect on the filing date and the interim rule in § 28.68(e).
Director discretion over “minor” alterations	What the Director considers “substantially in accord” may vary and affect permitted changes.	Ask for a written interpretation from the Director or request an official determination before committing funds; see § 28.68(f).
Mapping / record keeping	The PP requires a serial number referencing the rezoning petition file — locating the file is essential for understanding standards and any conditions.	Obtain the Department of Resource Management’s rezoning petition file (serial number on zoning map per § 28.68(b)).

Plain‑English summary

In unincorporated Solano County two overlay tools matter: the Travis Reserve Area (TRA) overlay protects specific lands for continued agriculture and explicitly blocks new residential development, and the Policy Plan (PP) overlay lets the County adopt parcel‑specific, project‑level zoning and standards (shown as “‑PP” on the zoning map) after a detailed review and findings. For both overlays, you must check the official zoning map and read the adopted overlay language for your parcel; the ordinance requires a detailed development plan and specific findings for PP adoption and imposes discretionary review for many non‑agricultural changes in the TRA. §§ 28.65, 28.68.

Information Gaps

The ordinance text in the provided materials describes overlay types and application/approval rules but does not list a machine‑readable map of which parcels are currently mapped TRA or PP. Map look‑ups and parcel‑specific determinations must be done with County GIS/zoning staff. Not found in retrieved materials.
A definitive treatment of accessory dwelling units (ADUs) within TRA is not spelled out in the overlay text; because the overlay states “No new residential uses are permitted”, whether ministerial ADUs qualify as an allowed accessory use is unclear from the text alone. Verify with the jurisdiction.
The PP overlay authorizes the County to craft site‑specific dimensional standards; therefore, any particular PP’s exact setbacks, height limits, or parking modifications are contained in its adopted ordinance/resolution — those specific numeric standards are not in the general PP section. Not found in retrieved materials.

Source References

Solano County Zoning Ordinance (Chapter 28), Special and Overlay Districts (Article VI) — see § 28.60 and the Park/TRA/PP subsections.
Travis Reserve Area (TRA) Zoning Overlay, rules and permitted uses — § 28.65.
Policy Plan Overlay (PP) Districts, purpose, application contents, findings, interim zoning, administration — § 28.68 (subsections (a)–(g)).
Nonconforming uses rules referenced for TRA (legal nonconforming residential uses) — § 28.114 (see TRA text referencing § 28.114).
Development standards tables and district‑by‑district dimensional examples (used for context where overlays defer to or modify base district standards) — Tables and development standards across Chapter 28 (see Tables 28.22B, 28.42B, etc.).

(For technical development standards, parking counts, design review triggers and architectural approval procedures, consult the County’s Development Standards, Parking, and Design Review pages.) /us/california/solano-county/development-standards /us/california/solano-county/parking /us/california/solano-county/design-review

Sources

Retrieved passages

Solano County Zoning Code (Chapter 28) High relevance
Solano County Zoning Code (Section 28-111) High relevance
Solano County Zoning Code (Section 11-111) High relevance
Solano County Zoning Code (Chapter 28) Medium relevance
Solano County Zoning Code (Section shall) Medium relevance
Solano County Zoning Code (Chapter 28) Medium relevance
Solano County Zoning Code (Section 28-99) Medium relevance
Solano County Zoning Code (Section and) Medium relevance

Cited sections

Solano County Zoning Ordinance (Chapter 28), **Special and Overlay Districts (Article VI)** — see **§ 28.60** and the Park/TRA/PP subsections. (Chapter 28)
**Travis Reserve Area (TRA) Zoning Overlay**, rules and permitted uses — **§ 28.65**. (§ 28.65)
**Policy Plan Overlay (PP) Districts**, purpose, application contents, findings, interim zoning, administration — **§ 28.68** (subsections (a)–(g)). (§ 28.68)
Nonconforming uses rules referenced for TRA (legal nonconforming residential uses) — **§ 28.114** (see TRA text referencing § 28.114). (§ 28.114)
Development standards tables and district‑by‑district dimensional examples (used for context where overlays defer to or modify base district standards) — Tables and development standards across Chapter 28 (see Tables 28.22B, 28.42B, etc.). (Chapter 28)
SolanoCounty_ZoningCode.md

Frequently asked questions

What is a Policy Plan Overlay (PP) in Solano County and when is it used?

A Policy Plan Overlay (PP) is a County overlay used to create parcel‑ or project‑specific zoning rules for large or mixed‑use developments; it combines zoning, master/precise plan functions, design standards and infrastructure planning in one process. A PP is added to the zoning map with the suffix “-PP” and is adopted only after the Board makes the findings listed in § 28.68(d).

What can I build on land inside the Travis Reserve Area (TRA) overlay?

Within the TRA, agrarian activities like crop production and grazing are allowed, and agricultural accessory structures under 2,500 ft² and 25 ft high are permitted; no new residential uses are allowed and other non‑agricultural uses generally require a Minor Use Permit or Use Permit. See § 28.65(B).

How do I know if my parcel is in an overlay (TRA or -PP)?

The County’s official zoning map shows overlays: a PP appears as the base district plus “-PP” and a serial number referencing the rezoning petition file; TRA is mapped as the Travis Reserve Area overlay. The ordinance requires checking the official map and rezoning petition file to see exact boundaries — verify with the County’s planning/GIS staff. See § 28.68(b).

Will a Policy Plan Overlay change setback, height, or parking rules?

Yes — a PP is expressly intended to set project‑specific height, building coverage, yard setbacks, and other development standards as part of the required development plan. Applicants must include these standards in their PP application per § 28.68(c) and should refer to the County’s Development Standards and Parking rules when preparing maps and calculations. /us/california/solano-county/development-standards /us/california/solano-county/parking

If my property is within a PP application under review, can I start new uses?

No — during PP review the ordinance limits property uses to those that were permitted under the zoning in effect at the time the PP application was filed (the “interim applicable zoning” rule). See § 28.68(e).

Are accessory residential units (ADUs) allowed inside the TRA?

The TRA states “No new residential uses are permitted.” Because ADUs are a form of residential development, ADU treatment inside the TRA is not clearly authorized by the overlay text in the materials retrieved; applicants should verify with the County and reconcile the overlay language with state ADU law. /us/california/california-adu-laws

Who approves PP overlays and what findings must the Board make?

A PP overlay is adopted by the Planning Commission and the Board of Supervisors by ordinance; the Board must find the PP is consistent with the General Plan, produces a stable and desirable character, meets development requirements and provides adequate mitigation for adverse impacts — see § 28.68(d) for the required findings.

Can the Director of Resource Management change an approved PP?

The Director may approve minor design, site, sign, and building alterations that are substantially in accord with an approved PP, provided the request is submitted in writing and explains why the change still conforms with the approved PP; see § 28.68(f). For anything beyond minor alterations, a formal amendment is required.

How are conflicts between overlay regulations and other County code sections resolved?

Where a conflict occurs between an overlay’s regulations and other provisions of the Zoning Ordinance, the overlay regulations specified in the PP chapter will prevail for development and uses within the overlay where the overlay expressly prescribes contrary regulations. See § 28.68(g).

Who enforces the TRA restriction on new residential uses?

The County enforces overlay rules through the permit/entitlement process; applicants seeking to construct or change uses in the TRA must obtain permits consistent with § 28.65, and existing nonconforming residences are handled under the County’s nonconforming rules (§ 28.114). Contact the Department of Resource Management for parcel‑specific enforcement guidance.

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