Local zoning · Manteca

Manteca — Nonconforming Uses

Q: What happens if my nonconforming building is damaged by fire?

If damage is involuntary and repair costs are less than or equal to 50% of the assessed value just prior to the damage, the structure may be rebuilt and reoccupied in the same form under a ministerial building permit, with time and diligence limits; if the rebuild expands beyond the original state, a Conditional Use Permit is required and up to 10% expansion may be considered. See § 17.12.070 .

Q: Who makes the decision on expanding a nonconforming use?

The Planning Commission is the designated approving authority for Conditional Use Permits, including those required for nonconforming expansions; the CUP findings specific to nonconforming uses must be met. See § 17.10.130 .

Nonconforming Uses under the Manteca local zoning and planning code, with the controlling citations.

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Last reviewed: July 2, 2026

Overview

This page explains how the City of Manteca’s Zoning Ordinance (Title 17) treats nonconforming uses, structures, and lots — i.e., uses or buildings lawfully established before the current code (or an amendment) but now inconsistent with it. It focuses only on Manteca rules (Chapter 17.12) and how they interact with district rules, development standards, and site approvals (for example, parking or design review). The rules allow continued operation in limited ways but restrict enlargement, rebuilding, and subdivision; specific procedures like a Conditional Use Permit are required for many changes. See the City’s Zoning overview for context at Manteca zoning & planning overview. § 17.12.010

What the Manteca code actually requires (quick legal points)

Continuation in perpetuity is allowed unless limited elsewhere, but the nonconforming use may not be enlarged or intensified beyond the area it lawfully occupied prior to the code change. § 17.12.030
Ordinary maintenance and safety-related structural repairs are allowed; replacement of an entire structure is not treated as routine maintenance. § 17.12.040
Modifications or expansions that would alter or increase the nonconforming aspect require a Conditional Use Permit (CUP), with findings specific to nonconforming expansions. § 17.12.050 and § 17.10.130
If a nonconforming structure is involuntarily damaged or destroyed, it may be reconstructed without Council action if repair costs are ≤ 50% of assessed value just before damage, subject to timing and permit rules; larger reconstructions/expansions require a CUP and the City will consider up to a 10% square-foot expansion. § 17.12.070
A nonconforming use that is abandoned or discontinued for six months or more loses its nonconforming status. § 17.12.080
Nonconforming lots can still be considered legal building sites if they meet specific historic-creation or approval criteria; subdivisions that would increase nonconformity are prohibited. § 17.12.020

District-by-district breakdown (Manteca-specific)

Note: the Manteca Zoning Title identifies base districts and overlays. For numeric setbacks, lot-area, lot coverage, and exact dimensional figures see Table 17.26.020-1 / § 17.26.020 (the Zoning District development standards table). Where the nonconforming rules below refer to actions (repair, expansion, CUP), those are governed by Chapter 17.12 and permitting rules such as § 17.10.130.

AG (Agricultural Zoning District)

Purpose & typical uses: agricultural production, accessory farm buildings, limited farm-related commercial uses. § 17.26.020
Nonconforming considerations: longstanding farm operations that conflict with new parcel sizes or use lists may continue but cannot be expanded to occupy more area than historically used; any enlargement or new permanent improvements likely require a CUP under § 17.12.050. § 17.12.030–.050

R‑E (Residential Estate)

Purpose & typical uses: large‑lot single‑family, estate residential; accessory structures incidental to residences. § 17.26.020
Nonconforming considerations: small pre-existing accessory structures or lot-dimension shortfalls are treated as nonconforming lots; building on such lots is allowed only when the lot meets one of the legal-building-site tests in § 17.12.020.C. § 17.12.020.C

R‑1 (One‑Family Dwelling)

Purpose & typical uses: single-family homes, typical neighborhood services as allowed. § 17.26.020
Nonconforming considerations: an existing use that becomes nonconforming (for example, an accessory commercial activity) may continue but cannot be enlarged; normal maintenance is permitted; conversion to a conforming residential use is allowed subject to applicable permit requirements. § 17.12.030–.040

R‑2 / R‑3 (Limited and Multiple‑Family)

Purpose & typical uses: duplexes, small apartments (R‑2) to larger multifamily developments (R‑3). § 17.26.020
Nonconforming considerations: multifamily properties with nonconforming elements follow the same Chapter 17.12 rules; where lot area or setbacks differ from today’s standard, the nonconforming-lot provisions can validate buildability if historical criteria are met. § 17.12.020.D–C

CN (Neighborhood Commercial) and CG / CM (Commercial)

Purpose & typical uses: neighborhood retail and services (CN), general retail and regional commercial (CG), and commercial/manufacturing mix (CM). § 17.26.020; § 17.20
Nonconforming considerations: in commercial districts the code explicitly allows certain on-site expansions that do not involve installation of permanent improvements without triggering full conformance; permanent improvements (building additions, new structures) will be subject to site plan and design review and may require a CUP for expansions of nonconforming aspects. § 17.12.020.F; § 17.12.050

BIP / M‑1 / M‑2 (Industrial / Business Park / Light & Heavy Industrial)

Purpose & typical uses: light manufacturing, warehouses, industrial parks (M‑1/BIP) to heavy manufacturing and distribution (M‑2). § 17.26.020; § 17.20
Nonconforming considerations: industrial sites with existing nonconformities (e.g., building location, parking) are allowed modernization for utilities and operations where there is no change of use or increase in area; changes that increase nonconformity or add permanent improvements typically trigger CUP/site review. § 17.12.020.E–G

OS / A / P / PQP (Open Space / Park / Public‑Quasi‑Public)

Purpose & typical uses: parks, open space, schools, government facilities. § 17.26.020
Nonconforming considerations: publicly‑owned facilities have limited exemption only to the extent they cannot be lawfully regulated; otherwise Chapter 17.12 applies. § 17.02.030; § 17.12.020.E

Overlay / Special Purpose Districts (e.g., CBD, PD, MP, SP)

Purpose & typical uses: overlay/special districts modify underlying standards. Overlay districts can impose separate rules that may be controlling; where the Master Plan or Specific Plan is more restrictive, it governs nonconforming rules for properties within that plan. Verify which set of rules applies to the parcel. § 17.26.020; § 17.12.020

Key Manteca rules — decision table

Issue / Action	Manteca rule	Code Reference
Continue an existing nonconforming use	Allowed to continue, transfer, or be sold; may not be enlarged or intensified beyond pre‑existing area	§ 17.12.030
Routine maintenance & safety repairs	Permitted; includes seismic retrofitting; replacement of a structure is not routine maintenance	§ 17.12.040
Modify or expand nonconforming structure/use	Requires approval per list in Chapter 17.12; structural modifications cannot create new nonconforming conditions; expansion typically requires a Conditional Use Permit	§ 17.12.050 and § 17.10.130
Repair/reconstruct after involuntary damage	Ministerial rebuild allowed if cost ≤ 50% of assessed value; larger repairs/expansions need CUP; City may allow up to 10% size increase	§ 17.12.070
Abandonment / loss of status	Continuous discontinuance for 6 months or more terminates nonconforming rights	§ 17.12.080
Nonconforming lot buildability	A nonconforming parcel can be a legal building site if it was: recorded subdivision, deeded before the zoning change, approved by Variance/lot-line adj, or government‑acquired partial takings meeting limits	§ 17.12.020.C
Parking/Loading shortfall	Not deemed by itself to create nonconforming use; existing off‑street parking cannot be reduced below original capacity	§ 17.12.020.F
Commercial site operational expansions	May add accessory uses without permanent improvements; permanent improvements subject to site plan/design review	§ 17.12.020.G

Checklist — what an applicant must generally satisfy (practical)

Document the historical lawful existence of the prior use or structure (proof required if claiming legal nonconforming status). § 17.12.030.D
Determine whether proposed work is maintenance (allowed), reconstruction after damage (see 50% rule), or an enlargement/change (CUP likely required). § 17.12.040; § 17.12.070; § 17.12.050
If an expansion or structural modification: prepare a Conditional Use Permit application and respond to CUP findings specific to nonconforming expansions. § 17.10.130
For reconstruction after involuntary damage: assemble building‑permit cost estimates and assessor value documentation to confirm the ≤50% standard or plan for a CUP if above. § 17.12.070
If the site is a small/nonconforming lot, assemble legal documents showing it meets one of the legal-building-site tests in § 17.12.020.C. § 17.12.020.C
Verify whether any Overlay or Master Plan covers the parcel; where a Master Plan is more restrictive it controls. § 17.26.020; § 17.12.020

Risks & Ambiguities

Issue	Why it matters	What to verify
Establishing "legal nonconforming" status	City requires evidence that the use/structure was lawful before the code changed — without it, no nonconforming protections	Collect deeds, permits, dated photos, business records; see § 17.12.030.D
Is a proposed action an enlargement vs maintenance?	Enlargement triggers CUP and stricter review; maintenance is allowed	Compare work scope to Chapter 17.12 definitions; when structural change or added area occurs, plan for CUP. § 17.12.040–.050
Damage threshold (≤50% of assessed value)	Over/under the threshold changes whether reconstruction is ministerial or requires discretionary review; cost valuation disputes are common	Obtain assessor value and prepare construction cost estimates to show whether ≤50% applies. § 17.12.070
Whether a change creates a “new nonconforming condition”	Adding a feature that creates a separate nonconformance can be prohibited	Confirm proposed work conforms to all applicable provisions where possible; Chapter 17.12 forbids creating new nonconformities. § 17.12.050.A
Subdivision and lot-line changes	Subdividing to increase nonconformity is prohibited and may revoke protections	Verify that any lot-line adjustment or subdivision does not increase nonconformity; see § 17.12.020.B
ADUs and nonconforming zoning interactions	State ADU law can limit how nonconforming zoning conditions are treated; Manteca’s Title 17 does not fully resolve that interplay	Not found in retrieved materials for a Manteca-specific ADU/nonconforming provision — verify with the Community Development Department and applicable state ADU law. Verify with jurisdiction. Not found in retrieved materials

Plain‑English summary

If a business or building in Manteca was legal before the current zoning changed, you can usually keep operating it — but you can't make it bigger or change it in ways that increase the rule-breaking without city approval. Routine fixes and safety work are okay; rebuilding after damage is allowed up to a cost threshold (≤ 50% of assessed value) without discretionary review, but larger reconstructions or enlargements need a Conditional Use Permit and the City must make specific findings. See Chapter 17.12 for the rules and check the underlying district standards in Table 17.26.020‑1. § 17.12.010–.080; § 17.26.020

Source References

City of Manteca Zoning Ordinance (Title 17) — Chapter 17.12, NONCONFORMING USES AND STRUCTURES: § 17.12.010 – § 17.12.080.
City of Manteca Zoning Ordinance — Conditional Use Permit procedures and findings: § 17.10.130.
City of Manteca Zoning Ordinance — Reconstruction/repair after damage: § 17.12.070.
City of Manteca Zoning Ordinance — Continuation, maintenance, and modification: § 17.12.030; § 17.12.040; § 17.12.050.
Manteca Zoning Districts and development standards (Table 17.26.020‑1 / § 17.26.020) — list of base districts: AG, R‑E, R‑1, R‑2, R‑3, CMU, DMU, BIP, CN, CG, CM, M‑1, M‑2, OS, A, PQP.
Definitions relevant to nonconforming uses (Nonconforming Lot / Nonconforming Use): Manteca Zoning definitions. (Definitions section).
Additional Manteca code sections referenced in text: nonconforming lot rules/exemptions § 17.12.020; parking/loading exemption § 17.12.020.F.

Other helpful materials (state-level context; NOT a substitute for Title 17 analysis):

California ADU guidance (state law context — consult for ADU/nonconformance conflicts): California ADU law and ADU handbook (uploaded).
California Building Standards reference for building‑permit and code compliance matters (technical building-code issues live in California Building Standards Code). (Note: building-code compliance is separate from Title 17 zoning rules.)

Sources

Retrieved passages

Manteca Zoning Code (§ 1) High relevance
CBC § 1 (Chapter may) High relevance
Manteca Zoning Code (Chapter apply) High relevance
Manteca Zoning Code (§ 1) High relevance
Manteca Zoning Code (Title was) High relevance
Manteca Zoning Code (§ 1) High relevance
CBC § 1 (Chapter shall) High relevance
Manteca Zoning Code (Title but) High relevance
Manteca Zoning Code (Title shall) High relevance
Manteca Zoning Code Medium relevance
Manteca Zoning Code (§ 66333) Medium relevance
CBC § 66321 (§ 66321) Medium relevance
Manteca Zoning Code (§ 66314) Medium relevance

Cited sections

Official Manteca code library

Frequently asked questions

How long can a nonconforming use continue in Manteca?

A lawful nonconforming use may continue in perpetuity unless otherwise restricted, but it cannot be enlarged or intensified beyond the area it lawfully occupied before the zoning change. This is established in § 17.12.030.

What happens if my nonconforming building is damaged by fire?

If damage is involuntary and repair costs are less than or equal to 50% of the assessed value just prior to the damage, the structure may be rebuilt and reoccupied in the same form under a ministerial building permit, with time and diligence limits; if the rebuild expands beyond the original state, a Conditional Use Permit is required and up to 10% expansion may be considered. See § 17.12.070.

If I stop using my nonconforming business for a while, do I lose rights?

Yes. A continuous discontinuance or abandonment of a nonconforming use for six months or more terminates the nonconforming status — the City treats subsequent uses as required to conform to current zoning. Refer to § 17.12.080.

Can I add a small addition to a nonconforming structure?

Small repairs and maintenance are allowed, and some structural alterations for safety are permitted, but any addition or enlargement that increases the extent of the nonconforming condition is restricted and typically requires a Conditional Use Permit per § 17.12.050 and CUP findings in § 17.10.130.

Are nonconforming parking shortfalls treated the same as other nonconformities?

No — failure to meet current parking requirements alone does not by itself create a nonconforming use; however, existing off‑street parking that was in use at the time of adoption cannot be reduced below the original capacity. See § 17.12.020.F.

Is a small lot that doesn’t meet today’s area rules still buildable?

Possibly. A lot that was lawful prior to the code change may be considered a legal building site if it meets one of the historic criteria (recorded subdivision, deed before the amendment, variance/lot line adjustment, limited public acquisition). See § 17.12.020.C.

Does Manteca allow commercial sites to expand on nonconforming lots?

Commercial sites can expand certain activities provided no permanent improvements are installed; installation of permanent improvements (building additions, new structures) will be subject to site plan/design review and likely discretionary review. See § 17.12.020.G.

If I want to change a nonconforming use to another nonconforming use, is that allowed?

A nonconforming use may not be changed to another nonconforming use without Planning Commission approval, and then only to a use that is of the same or more restricted classification. See § 17.12.060.

Who makes the decision on expanding a nonconforming use?

The Planning Commission is the designated approving authority for Conditional Use Permits, including those required for nonconforming expansions; the CUP findings specific to nonconforming uses must be met. See § 17.10.130.

Does Manteca’s zoning table tell me setback and height numbers for each district?

Yes — the numeric setbacks, heights, lot area, and coverage figures are in Table 17.26.020‑1 and the supporting text in § 17.26.020; use that table to determine the underlying district standards that a nonconforming structure would otherwise conflict with. § 17.26.020

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