Clark County permit staff outline ADU rules, fees and utility requirements at public learning lab

At a Clark County online ADU learning-lab presentation, county permit technicians Jess and Laurie explained the county's rules for accessory dwelling units and answered homeowner questions on zoning, utility connections and permitting.

The guidance matters because ADU rules differ sharply by zone and can trigger new utility work, recorded covenants and impact fees that affect costs and future property-division options. "An ADU is an accessory structure to the main residential structure," Laurie, a Clark County permit technician, said, defining the units the session covered.

County staff said urban ADUs may be detached or attached and generally may not exceed 1,000 square feet. For lots of at least 20,000 square feet, a single ADU may be up to 1,500 square feet and a property may have two ADUs so long as the combined area does not exceed 2,000 square feet. Rural ADUs must be attached to the primary residence either by a common wall or by a breezeway; the county said that attachment requirement stems from state law intended to limit unplanned density. "It is state law," April, a Clark County staff member, said when explaining why rural ADUs must be attached.

Speakers described other technical limits: urban ADU height is 24 feet (recently increased from 18 feet), and attached rural ADUs can reach 35 feet; setbacks follow zone-specific rules. A breezeway was defined as "a covered open-sided structure attached to both the primary residence and the ADU," with no length restriction so long as it meets building code requirements.

Impact fees and utilities were a frequent focus. Clark County assesses ADU impact fees for roads, parks and schools at 25% of the standard rate, staff said; guest houses and temporary hardship placements pay no impact fees. Every ADU requires approvals from water and sewer purveyors; for properties on septic, the Clark County Public Health Department must approve the septic system or require an upgrade. County staff warned that for properties inside the urban growth area, if a lot is within 300 feet of a sewer line the owner must extend sewer service to the furthest property line, a cost that can be significant.

Guest houses and temporary hardship placements follow different rules: guest houses cannot have stoves or standard kitchen hookups and have no square-footage limit but are restricted by zone and typically require a covenant preventing future split-off because they are not assessed impact fees. Hardship placements must be renewed every two years and are limited to qualifying family members, staff said.

Other practical details covered during the Q&A included addressing and parking: an ADU commonly receives a letter suffix (for example, "B") on the main address unless it has a separate driveway, in which case it may receive its own building number; permit applications must include a plot plan showing designated parking for the ADU. Converting an existing garage to an ADU is allowed if the structure is permanent, but building- and fire-code upgrades (including firewalling) may be required.

Staff said Clark County does not maintain a library of preapproved ADU plans; applicants may use permit-center videos, the county's Project Docs and LMS platforms, or schedule a free 30-minute Q&A appointment with a permit technician (available Tuesdays and Thursdays) for help with document naming and uploads. The Permit Center general line is staffed Monday–Friday, 8 a.m.–3 p.m., and the county recommended leaving contact details and the property parcel or address if callers reach voicemail.

Speakers repeatedly advised homeowners to consult the county's GIS to confirm zoning (urban zones typically begin with R-1 codes, while rural zones carry other designations) and to check with the land-use department when a proposed ADU would intersect other rules such as conditional-use permits for guest houses in agricultural or forest zones.

The session closed with reminders that some rules derive from state law (referencing the Growth Management Act) and that questions about rezoning or the comprehensive-plan update should be directed to community planning; staff said the county's comprehensive-plan update is ongoing and expected to conclude in December 2025.

For people considering ADUs, the presentation emphasized three next steps: verify zoning in the county GIS, contact the appropriate utility or the county health department for sewer/septic approval, and schedule a permit-center Q&A to review project documents before submitting a permit application.