Local zoning · San Diego County

San Diego County — Land Use

Land Use under the San Diego County local zoning and planning code, with the controlling citations.

Last reviewed: July 6, 2026

Overview

In unincorporated areas of San Diego County, “what can go where” is governed by the San Diego County Zoning Ordinance (Ordinance No. 1402, New Series) and several countywide planning regulations that function like overlays, including the Resource Protection Ordinance and the Specific Plan Street Setback Ordinance. The base zoning districts and their permitted/conditional use lists are set in the Zoning Ordinance; however, sensitive-lands and subdivision standards often narrow or condition what’s actually developable on the ground. Throughout this page, references apply only in unincorporated San Diego County and should be read together with the County’s broader zoning overview, zoning districts, development standards, design review, overlay districts, parking, nonconforming uses, and variances and exceptions.

Key rule of thumb: even when a use is allowed by base zoning, it may be prohibited, limited, or need extra findings inside sensitive lands (wetlands, floodways, steep slopes) or along mapped Specific Plan streets. See § 86.604 and § 84.205.

How the County’s land-use framework works (plain-English)

Base zoning sets permitted and conditional uses; where details are missing in this page, consult the Zoning Ordinance directly (Not found in retrieved materials; verify with the jurisdiction).
“Sensitive lands” overlays control uses and encroachments in wetlands, floodways and floodplains, and steep slopes, with hard caps and exceptions in § 86.604 .
Subdivisions in rural designations must cluster and avoid sensitive resources at minimum percentages, per § 81.401(r) and Table 81.401.1 .
Along Specific Plan streets, you may not build into mapped setback areas; the stricter rule (this chapter or the Zoning Ordinance) controls under § 84.202–§ 84.205 .
For vesting tentative maps, proposed land uses to be vested must be shown on an accompanying site plan under § 81.1203; vested rights are conferred per § 81.1205 .
Parkland dedication/fees apply to residential subdivisions and can affect site planning under § 810.102–§ 810.107 .

Sensitive Lands and Subdivision-Linked Land Use Controls

Resource Protection Overlay — Wetlands (unincorporated areas)

Purpose: Protect biological functions; only low-impact uses allowed. § 86.604 .
Typical permitted uses: Aquaculture that does not harm the ecosystem; scientific/educational/recreational uses that do not harm resources; removal of invasive species; wetland creation/restoration; necessary crossings for access with strict “least-damaging” methods and mitigation at minimum 3:1 (including at least 1:1 creation). § 86.604 .
Key dimensional/criteria: Crossings must be minimized and designed to avoid barriers to wildlife movement; impacts must be mitigated to “no net loss” with 3:1 mitigation minimum. § 86.604 .
Where it applies: Any mapped wetland or wetland buffer in unincorporated areas.

Resource Protection Overlay — Wetland Buffer Areas

Purpose: Maintain buffer functions adjacent to wetlands. § 86.604 .
Typical permitted uses: Improvements necessary to protect adjacent wetlands; all uses allowed in wetlands, provided no overall decrease in functions/values. § 86.604 .
Key criteria: No net decrease in biological values/functions; applicability triggered by mapped buffers. § 86.604 .

Resource Protection Overlay — Floodways

Purpose: Keep floodways free of obstructions and incompatible uses. § 86.604 .
Typical permitted uses: Agricultural, recreational, other low-intensity uses; mineral resource extraction only with a Major Use Permit and Reclamation Plan. Permanent structures for habitation or as a place of work are prohibited. § 86.604 .
Key criteria: Modifications must avoid increased erosion/sedimentation; hard limits on concrete/rip-rap channels absent necessity to protect existing buildings. § 86.604 .

Resource Protection Overlay — Floodplain Fringe

Purpose: Allow uses otherwise permitted by zoning while managing flood risk. § 86.604 .
Typical permitted uses: All uses permitted by base zoning and floodway-allowable uses, if criteria are met. § 86.604 .
Key criteria: Fill limited to achieving elevation and minimal function; landscaping to naturalize banks; development below 100-year flood elevation must withstand periodic flooding. § 86.604 .

Resource Protection Overlay — Steep Slope Lands

Purpose: Reduce grading and habitat loss on steep terrain. § 86.604(e) .
Typical permitted uses: Base-zoned uses constrained by encroachment caps; explicit exceptions include public roads, necessary local access, certain utilities, required fire-clearing, passive trails, “reasonable use” area on older lots, and ongoing agriculture. § 86.604(e) .
Key dimensional standards: Maximum allowed encroachment into areas ≥25% slope follows a sliding scale (see table below). Open-space easements typically required where ≥10% of a lot contains steep slope lands, with limited allowances for access and clearing. § 86.604(e) .

Steep slope encroachment allowances (≥25% slope)

75% or less of lot in steep slopes: 10% encroachment allowed
80%: 12%
85%: 14%
90%: 16%
95%: 18%
100%: 20% Code reference: § 86.604(e) .

Conservation Subdivision Designations — SR-10

Purpose: Cluster lots and avoid mapped sensitive resources in Semi-Rural designations. § 81.401(r) and Table 81.401.1 .
Typical permitted uses: Base-zoned residential and allowed rural uses; avoided/open-space areas limited to passive recreation, non-motorized trails, native landscaping, resource preservation, certain utilities/infrastructure; leach fields/brush clearing allowed only in SR-10 and RL-20 avoided areas. § 81.401(r) .
Key dimensional standards: Minimum 75% of mapped “avoided resources” must remain in open space. Table 81.401.1 (SR-10) .
Where it applies: Subdivisions in SR-10 areas in unincorporated County.

Conservation Subdivision Designations — RL-20

Purpose and allowed uses: Same framework as SR-10, with higher avoidance thresholds. § 81.401(r) .
Key dimensional standards: Minimum 80% of “avoided resources” in open space. Table 81.401.1 (RL-20) .

Conservation Subdivision Designations — RL-40

Purpose and allowed uses: Same; stricter avoidance. § 81.401(r) .
Key dimensional standards: Minimum 85% of “avoided resources” in open space. Table 81.401.1 (RL-40) .

Conservation Subdivision Designations — RL-80

Purpose and allowed uses: Same; highest avoidance. § 81.401(r) .
Key dimensional standards: Minimum 90% of “avoided resources” in open space. Table 81.401.1 (RL-80) .

Specific Plan Street Setback Overlay

Purpose: Safeguard mapped rights-of-way for planned major streets and maintain compatible setbacks. § 84.200–§ 84.206 .
Typical permitted uses: Base-zoned uses outside the mapped specific plan area and special setback area. Encroachment into these mapped areas is prohibited unless otherwise permitted by this chapter. § 84.205 .
Key standards:
- If this chapter’s setback rules conflict with zoning, the stricter setback prevails. § 84.202 .
- All structures must conform to this chapter in unincorporated areas. § 84.203 .

Decision-Relevant Land Use Tables

Sensitive lands — allowed uses and key criteria (unincorporated areas)

Sensitive Lands Category	What’s typically allowed	Key criteria that can block/limit use	Code Reference
Wetlands	Low-impact uses (aquaculture; scientific/educational/recreation), invasive removal, habitat restoration; access crossings if strictly necessary	No net loss; crossings minimized; “least-damaging” construction methods; 3:1 mitigation (≥1:1 creation)	§ 86.604
Wetland Buffers	Improvements to protect wetlands; uses allowed in wetlands	No overall decrease in biological values/functions	§ 86.604
Floodways	Agricultural/recreation; mineral extraction only with Major Use Permit + Reclamation Plan; no habitable/work structures	Channelization tightly limited; no increased erosion/sedimentation	§ 86.604
Floodplain Fringe	Uses allowed by base zoning and floodway, if criteria met	Fill limited to minimum; flood-resistant design below 100‑yr flood	§ 86.604

Conservation subdivision — minimum resource avoidance

General Plan Designation	Minimum percent of mapped “avoided resources” to remain open space	Code Reference
SR‑10	75%	§ 81.401(r), Table 81.401.1
RL‑20	80%	§ 81.401(r), Table 81.401.1
RL‑40	85%	§ 81.401(r), Table 81.401.1
RL‑80	90%	§ 81.401(r), Table 81.401.1

Subdivision-linked land use checkpoints

Major subdivisions must provide compliant access; roads/easements vary by area and ADT; public vs. private road decisions can reshape lot yield and feasible uses. § 81.402(b)-(i) .
Residential subdivisions must dedicate parkland, pay in-lieu fees, or both; this affects net developable acreage and layout. § 810.102–§ 810.107 .
Vesting tentative maps must include a site plan that shows the specific land uses you want vested; only depicted and approved features vest. § 81.1203–§ 81.1205 .

Checklist

Confirm base zoning and allowed uses on the parcel from the Zoning Ordinance use regulations (Not found in retrieved materials; verify with the jurisdiction and see zoning).
Screen the site for sensitive lands (wetlands, floodways/floodplains, steep slopes) and apply the stricter use/encroachment limits under the Resource Protection Ordinance. Cite constraints in your submittal. § 86.604 .
If subdividing in SR‑10 or RL‑20/40/80, design as a conservation subdivision and meet the minimum avoided-resource percentages. § 81.401(r) .
Check if a Specific Plan Street or special setback affects your frontage; avoid encroachments into mapped areas. § 84.202–§ 84.205 .
For a vesting tentative map, include the detailed site plan with proposed land uses to be vested. § 81.1203 .
If residential lots are proposed, account for parkland dedication or in‑lieu fee obligations early in site planning. § 810.102–§ 810.107 .
Coordinate any planned mineral extraction or borrow operations with Major Use Permit requirements. § 86.604 (floodway limits) ; grading/borrow linkage to Use Permits referencing Zoning Ordinance § 7374 .
Ensure any grading/open-space easements plan complies (no grading/clearing contrary to easement terms). § 87.112 .
Separate building code compliance lives under the California Building Standards Code; do not mix land-use approvals with building approvals.

Risks & Ambiguities

Issue	Why it matters	What to verify
Missing base-district use lists	Determines “by-right” vs. permit-required uses	Zoning Ordinance use regulations and any community plan overlays (Not found in retrieved materials)
Wetland/watercourse mapping uncertainty	Triggers strict use and mitigation standards	Field delineation and County acceptance for § 86.604 wetlands/buffers; confirm required mitigation ratios
Floodway vs. floodplain fringe linework	Habitable/work structures banned in floodway	Current FEMA/County flood maps; apply § 86.604 criteria for any proposed modifications
Steep slope percentage and encroachment math	Drives how much of a site can be graded/used	Slope analysis per County submittal standards; apply the encroachment table in § 86.604(e)
Conservation subdivision thresholds	Determines unavoidable open-space set‑asides	Applicability (SR‑10, RL‑20/40/80) and Table 81.401.1 percentages under § 81.401(r)
Specific Plan Street alignment	May force increased setbacks/limit site yield	Check adopted Specific Plan maps and apply § 84.202–§ 84.205
Park dedication vs. in‑lieu fees	Affects lot yield and financing	Whether land or fees are required and timing under § 810.102–§ 810.107

Plain-English Summary

In unincorporated San Diego County, land use starts with base zoning but is often narrowed by sensitive-lands overlays and subdivision rules. Expect tight limits in wetlands, floodways, floodplains, and on steep slopes, and—if you’re subdividing in rural designations—plan on clustering and preserving most mapped resources. If a Specific Plan Street touches your frontage, your effective buildable envelope can shrink. Before you design, confirm your base-district uses, sensitive‑land constraints, and whether parkland dedication or fees apply.

Information Gaps

County Zoning Ordinance district-by-district permitted and conditional use lists (e.g., RS, RM, A70/A72, C30–C36, M50–M54): Not found in retrieved materials.
Any countywide “use matrix” summarizing permitted/conditional uses by zone: Not found in retrieved materials.
Community plan-specific land use qualifiers (if any) on top of base zoning: Not found in retrieved materials.

Source References

Resource Protection Ordinance — permitted uses/criteria in wetlands, buffers, floodways, floodplain fringe, and steep slopes: § 86.604 .
Conservation Subdivisions — rural designations and avoidance thresholds: § 81.401(r) and Table 81.401.1 .
Specific Plan Street Setback Ordinance — applicability, conflicts, encroachment prohibitions: § 84.200–§ 84.206 .
Vesting tentative maps — filing with land-use site plan and vesting: § 81.1203–§ 81.1205 .
Parkland dedication and in‑lieu fees (subdivisions); fee timing: § 810.102–§ 810.107 .
Grading within open space easements (land‑use constraint): § 87.112 .

Sources

Retrieved passages

San Diego County Zoning Code Medium relevance
San Diego County Zoning Code Medium relevance
San Diego County Zoning Code Medium relevance
CBC § 810.105 (Section 810.105) Medium relevance
San Diego County Zoning Code (title constraints.) Medium relevance
San Diego County Zoning Code (Chapter shall) Medium relevance
San Diego County Zoning Code (Section 7374) Medium relevance
San Diego County Zoning Code (Section 4120) Medium relevance
CFC § 100 Medium relevance
San Diego County Zoning Code (Article for) Medium relevance
CBC § 810.105 (ARTICLE 4.) Medium relevance

Cited sections

Official San Diego County code library

Frequently asked questions

What land uses are allowed in wetlands in unincorporated San Diego County?

Very few. Low‑impact uses (like scientific/educational activities) and habitat restoration are allowed, and strictly necessary crossings may be permitted if impacts are minimized and mitigated at least 3:1 (with at least 1:1 creation). Most other development is prohibited. See § 86.604 for permitted uses and criteria .

Can I build a home or workplace in a mapped floodway?

No. Permanent structures for human habitation or as a place of work are not permitted in floodways. Only low‑intensity uses (agriculture/recreation) may occur; mineral extraction needs a Major Use Permit and a Reclamation Plan. See § 86.604 .

Are uses in the floodplain fringe the same as in the floodway?

The fringe is more flexible: uses otherwise allowed by zoning may occur if flood criteria are met (e.g., limited fill, flood‑resistant design). The floodway is much stricter. Details are in § 86.604 (floodplain fringe criteria) .

How much can I encroach into steep slopes?

There’s a sliding cap based on how much of the lot is ≥25% slope. For example, if 75% or less of your lot is steep slopes, up to 10% of that steep area may be encroached; at 100% steep slopes, up to 20% may be encroached. Exceptions exist for access roads, utilities, and fire‑clearing. See § 86.604(e) .

I’m subdividing rural land — how much open space must I preserve?

In conservation subdivisions, the County requires you to avoid and permanently protect a minimum share of mapped “avoided resources”: 75% (SR‑10), 80% (RL‑20), 85% (RL‑40), and 90% (RL‑80). See § 81.401(r) and Table 81.401.1 .

Do Specific Plan Street maps change my setbacks?

Yes. If a Specific Plan Street or its special setback area crosses your site, you may not build into those areas, and the stricter standard (this chapter or the Zoning Ordinance) applies. See § 84.202–§ 84.205 .

What must I submit to “vest” specific land uses with a vesting tentative map?

A complete site plan showing the proposed land uses to be vested. The County only vests what’s sufficiently detailed and approved with the vesting map. See § 81.1203–§ 81.1205 .

Will a residential subdivision trigger parkland dedication or fees?

Yes. Subdivisions must dedicate parkland, pay in‑lieu fees, or both; the timing and form are set in § 810.102–§ 810.107. Factor this into your site planning early .

Where can I find the list of permitted and conditional uses for my zone (e.g., RS, RM, A70)?

Those base‑district use lists live in the County Zoning Ordinance’s use regulations. They were not in the retrieved materials for this page. Verify with the County (Not found in retrieved materials).

Does grading inside a recorded open space easement affect land use?

Yes. Grading or clearing contrary to the easement terms is unlawful; plan your site and access accordingly. See § 87.112 .

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