Napa County, CA Home Business: Zoning & Home Occupation Permits (2026)
Key Facts
- Code Section
- NCC 18.104.090
- Max Floor Area Used
- 25% of dwelling gross floor area
- Employees
- Residents of the dwelling only
- Accessory Buildings
- Prohibited as the home-occupation location
- External Appearance
- No change permitted; no visible business evidence
- Off-Lot Impacts
- No detectable noise, vibration, glare, fumes, odors, or interference
- Sales Allowed
- Only goods produced on premises or services-related
- Wine Production
- Under 200 gal/yr, within 500 ft of residence, no on-site sales
Summary
Napa County Code 18.104.090 limits home occupations to the dwelling itself (no accessory buildings), confines them to 25% or less of the dwelling's gross floor area, restricts work to resident-occupants only, and prohibits any off-lot detectable noise, vibration, glare, fumes, odors, or electrical interference.
18.104.090 - Home occupations. The following rules and standards shall apply to each home occupation: A. No person other than those persons who are regular residents on the premises shall be engaged in such occupations. B. The use of the dwelling for the home occupation shall be clearly incidental and subordinate to its use for residential purposes by its occupants, and not more than twenty-five percent of the gross floor area of the dwelling unit shall be used in the conduct of the home occupation. C. There shall be no change in the outside appearance of the building or premises, or other visible evidence of the conduct of such home occupation. D. No home occupation shall be conducted in any accessory building. E. There shall be no sales in connection with such home occupation other than sales of merchandise produced on the premises or directly related to the services offered. F. No traffic shall be generated by such home occupation in greater volumes than would normally be expected in a residential neighborhood, and any need for parking generated by the conduct of such home occupation shall be met off the street and other than in a required front yard. G. No equipment or process shall be used in such home occupation which creates noise, vibration, glare, fumes, odors or electrical interference detectable off the lot to the normal senses. In the case of electrical interference, no equipment or process shall be used which creates visual or audible interference in any radio or television receivers off the premises, or causes fluctuations in line voltage off the premises. H. The nature or type of occupation for which a home occupation permit may be granted shall be a material part of such permit. I. Storage, warehousing or manufacturing of wine for sale on the premises is allowed only if the annual wine production, manufacturing and storage on the premises or within an accessory structure that is located within five hundred feet of the residence on the premises is less than two hundred gallons. The property owner shall submit a copy of their U.S. Department of the Treasury, Alcohol and Tobacco Tax and Trade Bureau (TTB) form annually to the department and on-site sales shall not be allowed. J. (Reserved). K. No home occupation shall be allowed unless an administrative permit has first been issued for such use pursuant to Chapter 18.126. (Ord. 1275 § 3, 2006: Ord. 1206 § 26, 2002: Ord. 1101 § 7, 1996; Ord. 759 § 12, 1983: Ord. 511 § 1 (part), 1976: prior code § 12404)
Full Breakdown
090, the home occupation must be 'clearly incidental and subordinate' to the residential use, and not more than 25% of the gross floor area of the dwelling unit may be used for it. Only persons who are regular residents on the premises may be engaged in the occupation - non-resident employees are not allowed. The home occupation may not be conducted in any accessory building. There must be no change in the outside appearance of the building or premises, and no visible evidence of the conduct of the home occupation.
Sales are limited to merchandise produced on the premises or directly related to the services offered. Traffic generated by the home occupation may not exceed what is normal for a residential neighborhood, and parking generated by the home occupation must be off-street and outside any required front yard. No equipment or process may be used that creates noise, vibration, glare, fumes, odors or electrical interference detectable off the lot to the normal senses; electrical equipment may not cause visual or audible interference in any off-premises radio or television receivers or cause off-premises line-voltage fluctuations.
The nature or type of occupation is a material part of the permit, meaning a change of business activity requires a new or modified permit. S. TTB form is submitted annually, and no on-site sales occur.
Violations & Fines
Exceeding the 25% floor-area cap, employing non-residents, operating in an accessory building, generating off-lot noise/odor/vibration/glare, or changing the type of occupation without amending the permit are all zoning violations under Title 18 enforceable through PBES Code Compliance. Remedies include notices of violation, administrative citations under the County Code, abatement, and revocation of the Home Occupation Permit.
Frequently Asked Questions
Can I run my business out of the detached garage or a shop building?
Can I hire an employee to work from my house?
Can a home occupation include a small winery?
Can customers tell from the street that a business operates here?
Sources & Official References
Other rules in Napa County
How Napa County compares: Easiest Cities to Run a Home Business·California rules heatmap·Compare Napa County to another location·View the California home business overview
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