Building permits, zoning and septic rules in Nevada County, California

Yes: unincorporated Nevada County requires a building permit for construction, and the county has a dedicated permit path for limited density owner-built rural dwellings on qualifying parcels that became operative February 13, 2025¹. The owner must hold the property or dwelling when applying and when the permit is issued, identify the project as owner-built, and satisfy the ordinance's rural-area, zoning, sewage-disposal-setback and CC&R criteria¹. The county identifies the Town of Truckee, Grass Valley and Nevada City as separate agencies, so a parcel inside one of them may need permits from that jurisdiction rather than the county¹³; Truckee has adopted the 2025 California Building Code for construction inside town limits¹⁴. Statewide, California's 2025 Building Standards Code applies to permit applications filed on or after January 1, 2026, and no building or structure may be built, enlarged or altered anywhere in the state without a separate permit from the local building official^15,16. A permit issued under the county's rural-dwelling ordinance is valid for three years from issuance, with one-year extensions available¹. Some agricultural work has a narrower exception: bona fide agricultural grading may be exempt after Building Department verification and an Agricultural Commissioner recommendation, while qualifying nonhabitable agricultural accessory structures must meet the county policy's zoning, size, spacing, setback and utility conditions¹⁷. California's contractor-licensing exemption lets an owner who builds on his or her own property skip a contractor license if the improvements are not intended or offered for sale and the owner personally does the work or directly hires licensed trade contractors; the exemption does not waive the county building permit¹⁸.

The Nevada County Building Department, part of the Community Development Agency, processes applications at the Permit Processing Center at the County Administrative Center, 950 Maidu Avenue, Suite 170, Nevada City; call 530-265-1222¹⁹. A standard application needs three complete sets of construction plans, three site plans, plan-check fees paid at submittal, and, for a new dwelling, two sets of septic design with a site plan¹⁹. Nevada County publishes separate schedules for building, plan review and inspection, environmental health, planning, public works, surveyor and traffic-mitigation fees; its current schedule took effect September 1, 2026²⁰. Inspections, including foundation/setbacks, roof sheathing and shear, rough, and final, require the applicant to request them and provide access at least 48 hours in advance¹. Once work is complete and approved, the building official issues a Certificate of Occupancy; a temporary certificate is available before full completion if approved sanitary facilities exist and safety standards are met, for a $185.48 processing fee plus a bond of at least $1 per square foot up to $2,000¹.

Nevada County's Zoning Regulations apply to all land uses and development within the unincorporated county, and the county publishes maps showing property-specific zoning boundaries and codes^2,21. Inside city limits the county's zoning rules do not apply: Nevada City applies its own zoning code and Grass Valley administers zoning under its own Development Code, so confirm which government controls an address before using either set of rules^3,4,7. In the county's Residential Agriculture (RA) and Single-Family (R1) districts, minimum parcel size runs from 10,000 square feet with public water and sewer up to 3 acres with private water and sewer, minimum road frontage is 120 feet in RA and 60 feet in R1, maximum building height is 35 feet or three stories, and maximum impervious surface is capped at 30% in RA and 40% in R1¹². Front-yard setbacks in these districts are generally 20 feet from a road right-of-way at least 50 feet wide, with interior and rear yards at 30 feet, though setbacks may be reduced on parcels under three acres under the ordinance's exceptions section¹². We could not confirm a local minimum dwelling floor area for unincorporated Nevada County; California's statewide efficiency-unit standard is 190 square feet of living space, and a county ordinance may allow 150 square feet, which we could not confirm Nevada County has adopted²²; ask the Planning Department about the parcel's zoning and any project-specific standard before designing a home.

In unincorporated Nevada County, the Environmental Health Department issues onsite wastewater treatment system (OWTS) septic permits, separate from the building permit^5,8. An On-Site Soils Evaluation must be completed before applying for the septic permit, and the applicant works with a licensed professional⁵. The county lists a $743.50 fee for a standard gravity-flow system and $989.10 for treatment systems such as mound or drip, and a construction permit expires one year after issuance⁵. The department inspects construction, and no system may operate without a Certificate of Satisfactory Completion⁸. A new-residence building permit cannot move forward until the septic approval is in place⁸. For a parcel inside Truckee, Grass Valley or Nevada City, we could not confirm who handles septic; ask the city or town and Environmental Health. Statewide, California's OWTS Policy puts the State Water Board and regional water boards in charge of oversight while local agencies like Nevada County implement their own approved management programs²³. Soils here make septic a central planning question: USDA soil survey data rates only about 0.1% of Nevada County's soils as free of severe limits for a conventional drain field, consistent with a county where under 11% of the land sits at 15% slope or less and nearly 88% is forested, steep, shallow, granitic Sierra foothill terrain that is genuinely difficult for conventional leach fields almost everywhere²⁴. Where a parcel is within Sanitation District 1 and public sewer is available, county rules require connecting to it instead of issuing a septic permit, and even a sub-750-square-foot ADU that's exempt from impact fees under SB 13 still owes ordinary sewer connection charges²⁵. If you're subdividing, a site approval report for sewage disposal is generally required before the map records, unless the resulting parcels are 40 acres or larger²⁶.

Renting a room in a home, or a whole primary residence, is allowed in unincorporated Nevada County if the structure is permitted for residential use, the operator registers with the Treasurer-Tax Collector, holds a Transient Occupancy Tax Certificate and pays Transient Occupancy Tax; the county's FAQ says no Planning Department permit is needed for these rentals⁶. Residential guest quarters may be used for non-paying guests only, and the county's FAQ says the same for recreational vehicles and tiny houses on wheels, which may host non-paying guests for up to 90 days per calendar year on a developed property⁶. An accessory dwelling unit built after April 25, 2019 required a deed restriction against short-term rentals at building permit issuance, so check the parcel's recorded restrictions with the Nevada County Clerk-Recorder before counting on rental income from an existing ADU⁶.

An ordinary RV cannot be permanent housing outside a mobilehome or special occupancy park unless a local ordinance allows otherwise¹⁰. On an unincorporated Nevada County parcel with no permanent dwelling, the owner may stay in a currently licensed RV for up to 90 total days between April 15 and October 15 without a Temporary Residence Permit, provided vegetation-clearance, fire-agency notification and fire-extinguisher requirements are met¹¹. Non-paying guests may also stay in an RV for up to 90 total days per parcel each calendar year when the parcel has a legally established permanent dwelling and the same safety conditions are met; this does not create a right to permanent RV housing¹¹. Nevada County separately allows a state-labeled Tiny Home on Wheels as a dwelling or ADU if it is no larger than 400 square feet excluding a qualifying loft and obtains zoning compliance and a building permit⁹. A Tiny Home on Wheels also needs a site-specific Fire Protection Plan in a High or Very High Fire Severity Zone or beyond the county's dead-end-road limit⁹.

1. Confirm your parcel is in the unincorporated county, not inside the City of Nevada City or another incorporated city with its own zoning⁷.
2. Check the parcel's zoning district, minimum lot size, setbacks and impervious-surface limits with the Planning Department before you finalize a site plan^2,12.
3. Get a soils evaluation and septic (OWTS) approval from Environmental Health, since it's required before a new-residence building permit can be issued^5,8.
4. For an owner-built project, confirm that you own the property or dwelling and that the parcel and project qualify for the county's limited density rural-dwelling permit path; this pathway still requires a building permit¹.
5. Submit three sets of construction plans and three site plans to the Building Department, with plan-check fees paid at submittal¹⁹.
6. If drilling a well, apply through a licensed California well driller; well permits are valid for one year from issuance²⁷.
7. Schedule required inspections with at least 48 hours' notice, and complete final inspections before requesting your Certificate of Occupancy¹.

Nevada County is steep and heavily forested: only about 10.9% of the land sits at 15% slope or less, nearly 87.8% is wooded, and federal land makes up about 35.5% of the county²⁴. That terrain drives the septic picture directly, with only 0.1% of soils rated free of severe limits for a conventional drain field, so a soils evaluation should be one of your first calls, not a formality near closing²⁴. The county also sees severe drought in about 34.5% of years, which is worth factoring into water-supply and wildfire planning alongside the county's own fire-severity-zone rules for structures like Tiny Homes on Wheels^9,24. The nearest city of 100,000 or more people is about 32 miles away²⁴. Property taxes run a relatively low effective rate around 0.7%, but the median bill is still about $4,468 a year given a typical home value around $625,332; farmland runs about $8,650 an acre²⁴. If a floodplain touches the parcel, know that placing fill there needs a use permit and environmental review, and any disturbance within 100 feet of a floodplain needs a management plan²⁸. A driveway that connects to a county road needs a Nevada County encroachment permit for work in the county right-of-way, which requires a site plan, insurance certificate and a traffic control plan, while a driveway onto a state highway needs a Caltrans encroachment permit from the District Encroachment Permits Office^29,30.