ADU Construction Cost Calculator for Reno

The figures published on this site put a garage conversion at $60,000 to $130,000, a small detached unit under 500 square feet at $120,000 to $220,000, a one-bedroom detached of 500 to 750 square feet at $180,000 to $320,000, a larger detached unit of 750 square feet and up at $250,000 to $450,000 and beyond, an attached ADU at $150,000 to $300,000, and a higher-end custom ADU at $400,000 and up. This calculator builds a number up from your own lot and specification and then tells you which of those tiers it lands in.

Usually: a service upgrade, the required off-street parking space, separate utility meters, landscape restoration after the trench, appliances, window coverings and light fittings, furniture, and the interest on whatever you borrowed. Some builders include some of these. The only way to know is to ask for an explicit exclusions list — and if a proposal does not have one, that is itself informative. The second section of this calculator exists to put numbers against exactly those lines.

Yes, and the reason is simple: the foundation, the walls and the roof already exist. This site publishes conversions at $60,000 to $130,000 against $120,000 to $220,000 for even a small detached unit. What you are giving up is control of the footprint, the ceiling height and the window placement — the unit will always be the shape of the garage — and you are giving up the garage. Two things routinely break the budget: a slab that was never poured to be lived on, and a panel that cannot carry a second dwelling.

Yes for any ADU. Independent northern Nevada sources put ADU permit timelines at roughly three to six months before construction starts. Reno adopted its ADU ordinance on 8 October 2025 with a minimum lot size of 5,000 square feet, at least one off-street parking space, and a requirement that the ADU be both smaller and shorter than the main house. Confirm the current requirements with the City of Reno or Washoe County — and confirm which of the two covers your parcel, because plenty of Reno addresses are unincorporated county.

Not reliably, and anyone who promises otherwise is guessing. What an ADU adds is a second dwelling with its own income or its own occupant, and its value depends on rents in your specific area, on whether the unit is legal and permitted, and on what a future buyer wants. The honest framing is that a permitted ADU is an income-producing asset that also happens to sit on your land, not a home improvement with a predictable return multiple. A licensed appraiser familiar with Washoe County is the person to ask.

That is when the ADU provisions of Nevada's AB 396, approved 6 June 2025, take effect. It covers counties over 100,000 — Washoe included — and cities over 60,000, so Reno and Sparks. From that date a local ordinance may not ban a separate kitchen, require more than one parking space, impose side or rear setbacks stricter than the primary residence, or prohibit long-term rental. It sets no statewide size cap and no fee limits. Properties inside the Tahoe Regional Planning Agency area, which includes Incline Village, are excluded, and private HOA covenants are untouched.