Local zoning · Clearlake

Clearlake — Nonconforming Uses

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

Last reviewed: July 6, 2026

Overview

Clearlake regulates nonconformities in three buckets: nonconforming uses, nonconforming lots, and nonconforming structures within Chapter XVIII, Zoning Regulations. The code lets many lawful pre‑existing situations continue, but it narrows expansions, sets abandonment rules, and charts pathways to bring sites closer to current standards over time. For a big‑picture context on how your base zone and uses interact, see the Clearlake zoning & planning overview and the base-zone matrix at Clearlake Zoning.

Key rule in plain English: if a nonconforming use stops for a continuous six months, the City treats it as abandoned and the site must thereafter meet current zoning for that district (§ 18-23.020(e)(1)). Abandonment includes a stop “for any reason, regardless of intent to resume” (§ 18-23.020(e)(2)).

What counts as “Nonconforming” in Clearlake

Definitions:
- A nonconforming use is a legal use established before the current zoning that no longer conforms to today’s district regulations (§ 18-45.010).
- A nonconforming structure is a legal building that no longer meets standards like setbacks, height, or area in its district (§ 18-45.010).
- A nonconforming lot is a legal lot with less area/dimensions/frontage than what the current district requires (§ 18-45.010).

Nonconforming Uses — Citywide Rules (Article 18-23)

Continued operation:
- A use that became nonconforming due to a zoning change may continue if it was legal when established and is not a nuisance (§ 18-23.020(a)).
When a “permitted” use becomes a “conditional use”:
- If the code change makes your formerly permitted use now require a conditional use permit (CUP), it is a nonconforming use unless and until you secure a CUP under Article 18-28 (§ 18-23.020(b)).
Enlargement or alteration:
- Except for dwellings, a building devoted to a nonconforming use may not be enlarged, extended, reconstructed, substituted, or structurally altered unless converted to a conforming use, or as allowed by the substitution/alteration path below (§ 18-23.020(c)).
“Substitution or alteration” path (CUP required):
- The Planning Commission may approve changing or substantially altering a nonconforming use if it reduces discrepancies with district requirements, using these criteria (§ 18-23.020(d)):
  - New use directly relates or is complementary to the site’s permitted uses.
  - New use reduces parking/traffic/congestion.
  - Not detrimental to habitability of adjacent properties.
  - Appearance won’t detract from neighborhood character.
One‑time expansion for legally nonconforming industrial uses (Director approval):
- The Director may approve a single expansion for an industrial use legally nonconforming due to zoning, subject to:
  - Consistency with the City’s Design Review Manual (Article 18-33),
  - Full screening of outdoor storage/operations, and
  - Bringing the site into compliance with performance standards in Article 18-22 (§ 18-23.020(d)).
- Expect this to implicate Clearlake Design Review and citywide Clearlake Development Standards.
Cessation/abandonment:
- Six months of continuous cessation = abandonment; after that, only conforming uses are allowed (§ 18-23.020(e)(1)–(2)).
- Safety repairs to unsafe buildings are allowed (§ 18-23.020(e)(3)).
- Note: another code passage references a Director’s ability to extend a “one-year limit” for cessation upon written request, which conflicts with the six‑month standard shown above (§ 18-23.020(e), cross‑reference). Verify with the City.

Nonconforming Structures — Citywide Rules (Article 18-25)

Rebuilding after damage:
- If damage is more than 60% of appraised value (exclusive of foundation), the structure cannot be reconstructed for the nonconforming use/condition (§ 18-25.020(a)(1)). If damage is less than 60% above the foundation, rebuilding to prior use/condition is allowed if substantially completed within six months (§ 18-25.020(a)(2)).
- Increasing square footage of a nonconforming residential structure does not count as an enlargement for this damage‑rebuild rule if no new dwelling unit is created and all other development standards are met (§ 18-25.020(a)(3)).
Repairs and alterations:
- Normal repairs to keep the structure sound are allowed (§ 18-25.020(b)(1)).
- Alterations are allowed only if consistent with all applicable district standards (§ 18-25.020(b)(2)(a)).
- Legally built single‑family and duplex structures may be altered (§ 18-25.020(b)(2)(b)).
- Accessory structures/garages legally built before they became nonconforming may be altered/expanded, provided parking requirements remain compliant; they cannot be expanded/converted to habitable space (§ 18-25.020(b)(2)(c)).
- An ADU or JADU that conforms with this chapter will not be required to correct a nonconforming zoning condition (§ 18-25.020(b)(2)(d)). See Clearlake ADUs.
Relocation:
- A nonconforming structure cannot be moved unless it meets all applicable standards at the new location (§ 18-25.020(c)).
Separate residential rebuild exception:
- Independently, Clearlake allows residences in RR, LDR, MDR, HDR, DC, GC, and MUX zones involuntarily damaged/destroyed by more than 50% to be rebuilt to the same density and up to the same size if certain timing and safety findings are met (§ 18-20.020(e)).

Nonconforming Lots — Citywide Rules (Article 18-24)

Merger expectation:
- If a nonconforming lot has been in common ownership with a contiguous property at any time since November 16, 1987 and it otherwise meets Government Code § 66451.11 merger criteria, it may not be developed individually—development may proceed only after merger or resubdivision to create one or more conforming parcels or one that “more nearly conforms” (§ 18-24.020(a)).
Administrative exception:
- The Director may approve an administrative use permit to retain existing lot lines if neighborhood character is maintained and convenient, conforming access and parking are available (§ 18-24.020(a)). This is a discretionary finding—coordinate early.
LDR/MDR leniency:
- In LDR and MDR, the merger/resubdivision rule does not apply when each commonly owned parcel meets at least 80% of minimum area, width, depth, and frontage (§ 18-24.020(b)).

How your base zone shapes “nonconforming” status

Whether a use is “nonconforming” depends on today’s use tables and development standards for your district (Tables 4–6; Article 18-20). For development standards like yards, height, and coverage, see Clearlake Development Standards; parking standards appear in § 18‑20.090 and Clearlake Parking. Overlay designations can also matter; check Clearlake Overlay Districts.

Rural Residential (RR)

Purpose: Not found in retrieved materials.
Typical permitted uses: Single‑family dwellings and agricultural/rural support uses appear allowed in RR under Table 4 (e.g., agriculture support) (§ 18-18.020; Table 4).
Key dimensional standards:
- Yards (other yards): Rear 10 ft; side 5 ft (Table 14; § 18-20.040).
- Height: 35 ft; up to 45 ft by administrative use permit (§ 18-20.060, Table 19).
Where it applies: Not found in retrieved materials.

Low Density Residential (LDR)

Purpose: Not found in retrieved materials.
Typical permitted uses: Single‑family dwellings, ADUs/JADUs; some agricultural support uses per Table 4 (§ 18-18.020).
Key dimensional standards:
- Yards (other yards): Rear 10 ft; side 5 ft (Table 14; § 18-20.040). Street yard cases for corners apply (Table 17) (§ 18-20.040).
- Height: 35 ft; up to 45 ft by administrative use permit (§ 18-20.060, Table 19).
Where it applies: Not found in retrieved materials.

Medium Density Residential (MDR)

Purpose: Not found in retrieved materials.
Typical permitted uses: Single‑family; multifamily by administrative permit; ADUs/JADUs per Table 4 (§ 18-18.020).
Key dimensional standards:
- Density: 15 units/acre (§ 18-5.020(a)).
- Yards: See § 18-20.040 (other yards rear 10 ft/side 5 ft; Table 14).
- Coverage: 60% (§ 18-5.020(c)). Height: 45 ft (§ 18-5.020(d)). Lot area: 5,000 sf (§ 18-5.020(e)).
Where it applies: Not found in retrieved materials.

High Density Residential (HDR)

Purpose: Provide higher‑density housing for smaller households/group housing, near employment/college areas (§ 18-6.010).
Typical permitted uses: Multifamily, ADUs/JADUs per Table 4 (§ 18-18.020).
Key dimensional standards:
- Density: 25 units/acre (§ 18-6.020(a)). Coverage: 60% (§ 18-6.020(d)). Height: 45 ft (§ 18-6.020(c)). Lot area: 5,000 sf (§ 18-6.020(e)). Yards: § 18‑20.040.
Where it applies: Areas designated “High Density Residential” on the General Plan Zoning Map (§ 18-6.010).

Mixed‑Use (MUX)

Purpose: Enable mixed residential/nonresidential projects and live‑work in appropriate areas, strengthen street life and reduce auto trips (§ 18-7.010).
Typical permitted uses: Mixed-use housing, residential, compatible commercial (Tables 4–5).
Key dimensional standards:
- Density: Up to 25 density units/acre, subject to General Plan designation (§ 18-7.020(a)). Height: 35 ft; up to 65 ft in cases meeting stated performance standards (§ 18-7.020(c)). Yards: § 18‑20.040.
Where it applies: “Appropriate areas” per code purpose; Verify precise mapped locations.

Downtown Commercial Mixed‑Use (DC)

Purpose: Not found in retrieved materials.
Typical permitted uses: General retail, restaurants, offices (Table 5); residential encouraged in DC (§ 18‑8.020(e)).
Key dimensional standards:
- Height: 35 ft, but 25 ft maximum on the lake side of Lakeshore Drive (§ 18‑20.060, Table 19); additional height up to 65 ft may be allowed if all listed performance standards are met (§ 18‑8.020(c)). Yards: § 18‑20.040. Driveway approaches require an administrative use permit to preserve pedestrian orientation (§ 18‑8.020(e)). Parking: § 18‑20.090.
Where it applies: Verify with the City’s Zoning Map.

General Commercial (GC)

Purpose: Provide sites for diverse, visitor‑serving and resident‑serving commercial uses that are visually pleasing and accessible (§ 18-9.010).
Typical permitted uses: General retail, offices, hotels/motels, restaurants (Table 5) (§ 18‑18.030).
Key dimensional standards:
- Height: 35 ft; up to 50 ft with a CUP; 35 ft max on lake side of Lakeshore Drive (§ 18‑9.020(c); § 18‑20.060). Yards: § 18‑20.040. No maximum coverage (§ 18‑9.020(d)). Min lot: 3,000 sf (§ 18‑9.020(e)). Parking: § 18‑20.090.
Where it applies: Verify with the City’s Zoning Map.

Industrial (IN)

Purpose: Provide locations for wholesale/heavy commercial/industrial activities conducted within buildings, with performance standards to protect residents and the environment (§ 18‑10.010).
Typical permitted uses: Light industry; storage/trucking by permit; industrial communications/transportation uses (Table 6) (§ 18‑18.040).
Key dimensional standards:
- Height: 35 ft (higher by CUP) (§ 18‑10.020(b); § 18‑20.060). No max coverage (§ 18‑10.020(c)). Min lot: 3,000 sf (§ 18‑10.020(d)). Yards/Parking: §§ 18‑20.040, 18‑20.090.
Where it applies: Verify with the City’s Zoning Map.

Open Space (O)

Purpose: Permanently apply to lands suitable for open space due to natural features/hazards; prevent subdivision and protect resources (§ 18‑11.010). Applied to General Plan “open space” or “park” lands (§ 18‑11.010(c)).
Typical permitted uses: Open space and related public uses; commercial/industrial uses generally not listed. See Tables 4–6 for limited allowances and permits.
Key dimensional standards:
- Yards: Front 35 ft; side 15 ft (30 ft street side on corners); rear 20 ft; special lake/creek rear yard note (§ 18‑11.020(b)). Minimum lot area varies by ownership (up to 40 acres for State/Federal; 5,000 sf for City/other agencies; private = existing size when reclassified) (§ 18‑11.020(c)).

Quick decisions for nonconformities (selected)

Topic	What the code allows or restricts	How to proceed	Code Reference
Keep operating a nonconforming use	Allowed if it was lawful and is not a nuisance	Maintain use; avoid cessation; confirm no nuisance	§ 18-23.020(a)
Formerly permitted use now needs CUP	Becomes a nonconforming use until CUP is issued	Apply for CUP under Article 18‑28	§ 18-23.020(b)
Expand/alter nonconforming use (non‑dwellings)	Prohibited unless converted to a permitted use or approved as a substitution/alteration	Consider use change, or apply for CUP to reduce discrepancy	§ 18-23.020(c)–(d)
One‑time expansion of legal nonconforming industrial use	Possible at Director level with screening and design/performance upgrades	Prepare plans addressing Design Review Manual and performance standards	§ 18-23.020(d)
Pause in operations	Six consecutive months = abandonment regardless of intent	Avoid continuous cessation; document operations	§ 18-23.020(e)(1)–(2)
Rebuild after damage (nonconforming structure)	>60% damage: cannot rebuild to same nonconformity; ≤60%: rebuild allowed within 6 months	Verify valuation; schedule rebuild	§ 18-25.020(a)
Residential rebuild after involuntary loss	May rebuild at same density/size if timing and safety findings are met	Use this as an alternative pathway	§ 18-20.020(e)
ADU/JADU on a nonconforming site	ADU/JADU approval cannot be conditioned on correcting a zoning nonconformity	Pursue ADU under local ADU standards	§ 18-25.020(b)(2)(d)
Nonconforming lots	Merger may be required; exceptions possible; LDR/MDR 80% leniency	Title check; consider AUP for exception	§ 18-24.020(a)–(b)

Checklist

Confirm the use/structure/lot was lawful when established and identify today’s base zone on the City map (see Clearlake Zoning).
For nonconforming uses, document continuous operation to avoid “abandonment” under 6‑month cessation rule (§ 18‑23.020(e)(1)).
If your use shifted from permitted to conditional, prepare a CUP application per Article 18‑28 (§ 18‑23.020(b)).
For any proposed alteration/expansion, check if it’s prohibited, allowed with CUP (substitution/alteration), or allowed for dwellings under Article 18‑25 (§ 18‑23.020(c)–(d); § 18‑25.020).
If industrial and legally nonconforming, consider the one‑time Director expansion path; align with the Design Review Manual and Article 18‑22 performance standards (§ 18‑23.020(d)). Coordinate Clearlake Design Review.
For structures damaged/destroyed, evaluate both Article 18‑25’s 60% rule and the residential rebuild exception at § 18‑20.020(e).
For nonconforming lots, order a title report (common ownership since 1987); assess merger triggers and potential AUP exception (§ 18‑24.020).
Factor in yards, height, coverage, and parking in your district (Article 18‑20; Clearlake Development Standards; Clearlake Parking).
If your site is in a combining/overlay district, check additional constraints (e.g., Scenic Corridor SC) (Clearlake Overlay Districts).
Coordinate building safety work with the California Building Standards Code (repairs to correct unsafe conditions are allowed under § 18‑23.020(e)(3)).

Risks & Ambiguities

Issue	Why it matters	What to verify
Abandonment period conflict	One place says 6 months; another references a Director extension of a “one‑year limit”	Ask Community Development which standard is controlling and whether extensions are available (§ 18‑23.020(e)).
“Except for dwellings” in expansion ban	Could be read to allow dwelling alterations where other uses are barred	Coordinate dwelling changes under Article 18‑25 and district standards (§ 18‑23.020(c); § 18‑25.020).
60% damage valuation	Threshold uses “appraised value for tax purposes”	Confirm valuation basis/timing with the Assessor and City (§ 18‑25.020(a)).
Residential rebuild exception vs. 60% rule	§ 18‑20.020(e) can allow same density/size after >50% loss	Which path applies to your case; timing windows and findings (§ 18‑20.020(e); § 18‑25.020).
Industrial one‑time expansion	Scope of “one time,” required upgrades, and screening	Pre‑application with Director; consistency with Design Review Manual and Article 18‑22 (§ 18‑23.020(d)).
Nonconforming lot “common ownership” since 1987	Title history can force merger or preclude standalone development	Title report; AUP exception feasibility; 80% rule in LDR/MDR (§ 18‑24.020).
Accessory structures and parking	Garage alterations must keep parking compliant; no habitable conversions	Check parking counts/layout with Planning/Engineering (§ 18‑25.020(b)(2)(c); § 18‑20.090).

Plain-English Summary

If your use, building, or lot doesn’t meet today’s rules but was legal when created, Clearlake generally lets it stay—so long as you don’t expand it in ways the code disallows, cause a nuisance, or let it sit idle too long. There are targeted off‑ramps: you can seek a CUP to swap in a less impactful use, some residential rebuilds can match prior size/density after disasters, ADUs don’t have to fix old zoning quirks, and one‑time industrial expansions can be approved if you upgrade the site. When in doubt, verify your base zone and talk to the City before changing anything.

Source References

Nonconforming Uses: §§ 18-23.010–18-23.020 (intent, continuation, CUP shift, enlargement limits, substitution criteria, industrial one‑time expansion, cessation/abandonment).
Nonconforming Lots: §§ 18-24.010–18-24.020 (merger; AUP exception; LDR/MDR 80% rule).
Nonconforming Structures: §§ 18-25.010–18-25.020 (60% damage rule; alterations; accessory structures; ADU/JADU clause; relocation).
Definitions: § 18-45.010 (nonconforming lot/structure/use).
Development Standards: § 18-20.040 Yards; § 18‑20.050 Coverage; § 18‑20.060 Height (Table 19); § 18‑20.090 Parking.
Use Tables: Article 18‑18 (Tables 4–6) for permitted/conditional uses by zone.
Zone Purposes/Standards cited: GC (§§ 18‑9.010–.020), IN (§§ 18‑10.010–.020), HDR (§ 18‑6.010–.020), MUX (§§ 18‑7.010–.020), O (§§ 18‑11.010–.020), DC property standards (§ 18‑8.020).

Sources

Retrieved passages

Clearlake Zoning Code (article to) High relevance
Clearlake Zoning Code (Article 18-33) High relevance
Clearlake Zoning Code (Section 66451.11) High relevance
Clearlake Zoning Code (Article 18-22.) High relevance
Clearlake Zoning Code (chapter will) High relevance
Clearlake Zoning Code (article to) High relevance
CBC § 66321 (§ 66321) Medium relevance
Clearlake Zoning Code (Section 18-19.353) Medium relevance
CBC § 286 Medium relevance
CBC § 66314 (§ 66314) Medium relevance
Clearlake Zoning Code (section is) Medium relevance
Clearlake Zoning Code Medium relevance
Clearlake Zoning Code (Article Standards) Medium relevance
Clearlake Zoning Code (§ 66333) Medium relevance
Clearlake Zoning Code Medium relevance
Clearlake Zoning Code (Article 18-28) Medium relevance
CBC § 65915 (Article 18-15.) Medium relevance
Clearlake Zoning Code Medium relevance
Clearlake Zoning Code (Article 18-20) Medium relevance
Clearlake Zoning Code Medium relevance
Clearlake Zoning Code (Article 18-20) Medium relevance
Clearlake Zoning Code Medium relevance
CBC § 271 Medium relevance
CBC § 286 (Section B) Medium relevance
Clearlake Zoning Code (Section 18-19.110) Medium relevance
Clearlake Zoning Code Medium relevance
CBC § 18 (Section 18-28.030.) Medium relevance
Clearlake Zoning Code Medium relevance

Cited sections

Nonconforming Uses: §§ 18-23.010–18-23.020 (intent, continuation, CUP shift, enlargement limits, substitution criteria, industrial one‑time expansion, cessation/abandonment). (§ 18-23.010)
Nonconforming Lots: §§ 18-24.010–18-24.020 (merger; AUP exception; LDR/MDR 80% rule). (§ 18-24.010)
Nonconforming Structures: §§ 18-25.010–18-25.020 (60% damage rule; alterations; accessory structures; ADU/JADU clause; relocation). (§ 18-25.010)
Definitions: § 18-45.010 (nonconforming lot/structure/use). (§ 18-45.010)
Development Standards: § 18-20.040 Yards; § 18‑20.050 Coverage; § 18‑20.060 Height (Table 19); § 18‑20.090 Parking. (§ 18-20.040)
Use Tables: Article 18‑18 (Tables 4–6) for permitted/conditional uses by zone. (Article 18)
Zone Purposes/Standards cited: GC (§§ 18‑9.010–.020), IN (§§ 18‑10.010–.020), HDR (§ 18‑6.010–.020), MUX (§§ 18‑7.010–.020), O (§§ 18‑11.010–.020), DC property standards (§ 18‑8.020). (§ 18)
Clearlake_ZoningCode.md

Frequently asked questions

Can I keep running my business if zoning changed and now requires a CUP?

Usually yes, but it becomes a nonconforming use until you secure a conditional use permit under Article 18‑28. The code allows continued operation if the use was lawful and is not a nuisance, and it explicitly treats formerly permitted uses that now need a CUP as nonconforming until a CUP is obtained (§ 18‑23.020(a)–(b)).

How long can I pause a nonconforming use before I lose it in Clearlake?

Six months of continuous cessation is considered abandonment regardless of intent to resume; the site then must conform to the current district’s uses (§ 18‑23.020(e)(1)–(2)). Another passage references a Director’s ability to extend a “one‑year limit,” which conflicts—verify the City’s current practice before relying on any extension.

I own a nonconforming industrial use. Can I expand?

Possibly once. The Director may approve a one‑time expansion if you screen all outdoor operations, meet the Design Review Manual, and bring the site into compliance with Article 18‑22 performance standards (§ 18‑23.020(d)). Expect coordination with Clearlake Design Review.

My nonconforming house was damaged by a fire. Can I rebuild?

If damage above the foundation is less than 60% of appraised value, you may restore and reuse it if you substantially complete work within six months (§ 18‑25.020(a)(2)). Also, a separate residential exception may allow rebuilding to prior density/size after involuntary destruction in listed zones if timing and safety findings are met (§ 18‑20.020(e)).

Can I add an ADU if my home has old setback or height nonconformities?

Yes. The code says an ADU or JADU that conforms to ADU standards will not be required to correct a nonconforming zoning condition (§ 18‑25.020(b)(2)(d)). See local steps at Clearlake ADUs.

What happens with small, older platted lots that don’t meet today’s size?

They may be subject to merger if held in common ownership with a neighbor since 1987 and otherwise meet State merger criteria (§ 18‑24.020(a)). In LDR/MDR, parcels at least 80% of required dimensions are exempt from the merger/resubdivision rule, and the Director can consider an administrative use permit to keep lot lines where neighborhood character/access/parking are maintained (§ 18‑24.020(a)–(b)).

I want to swap my nonconforming use for something milder. Is there a path?

Yes—through a CUP. The Planning Commission can approve a substitution/alteration if the new use is complementary to permitted uses, reduces parking/traffic issues, isn’t detrimental to neighbors, and the appearance won’t detract from neighborhood character (§ 18‑23.020(d)).

Do downtown (DC) height rules affect nonconforming status?

They can. DC has a 35 ft cap and a stricter 25 ft cap on the lake side of Lakeshore Drive (§ 18‑20.060, Table 19). A use or structure that exceeded today’s height when built can be nonconforming; expansions must then follow the Article 18‑23 and 18‑25 limits.

Are garage conversions allowed on nonconforming lots?

Not as habitable space if the garage is a nonconforming accessory structure. Nonconforming garages and storage buildings may not be expanded/converted to habitable space; any alteration must keep parking compliant (§ 18‑25.020(b)(2)(c)).

Do I need design review to alter a nonconforming site?

It depends on what you’re doing. For the one‑time expansion of a legally nonconforming industrial use, the Director must find the expansion consistent with the Design Review Manual and performance standards (§ 18‑23.020(d)). Other projects may trigger design review as provided elsewhere in the code; verify case‑by‑case.

Ask about any Clearlake property

Get a cited, plain-English answer on Clearlake zoning, setbacks, FAR, ADUs and permits — for any address.

Start Free Trial