A cottage in the backyard, a suite joined to the house or a converted garage, each with its own kitchen, bath and door, planned around zoning and run by one lead.
Think of an ADU as a second, smaller house sharing your lot, with a door, kitchen, bath and sleeping space all its own. It can sit apart in the yard, share a wall with your home or fill an old garage.
Zoning comes first. How large it can be, how near the property line and whether a tenant can live there all vary by county and city, so that gets confirmed before any pricing.
Freestanding units need a new slab or crawlspace and fresh framing. A garage conversion keeps its shell but usually needs reinforcing and new interior walls.
Lines trenched out from the main house and tied in. How far they have to travel is one of the biggest cost factors in the whole build.
Cabinets, a full bathroom, a sleeping area, lighting and heat and air, finished to the level you'd expect in your own house.
A parent, a grown child or a long-term tenant each point to a different layout, a different level of privacy and a different finish budget.
A garage conversion reuses an existing slab and walls, which can trim cost, at the price of your parking. A detached cottage costs more but keeps both.
Whether you can rent the unit, and to whom, is set by zoning. Confirm it before counting on the income in your plans.
Plan on several months for a freestanding unit after approvals come through; converting a garage is usually quicker. Size, foundation work and how far the utility trench runs move both the calendar and the cost.
That's a zoning question first. Lot size, setbacks and the local rules on secondary units decide it, and we'd confirm those before talking layout or price.
Start with the basics: lot size, where the house sits on it and what you picture the unit being used for. From there we can sort out what to check first.
