Detached ADU: What It Is & Cost in California

A detached ADU is a standalone backyard home—perfect for family living or rental income in Sacramento

Hey, so you’re looking at that backyard space and thinking a detached ADU might be the way to go — maybe for your parents to have their own little place but still be close enough for help, or for your grown kids to have independence without leaving the property, or even to turn it into a rental that brings in some extra cash and bumps up your home's value over time. It’s one of the most common things people ask me about around Sacramento.

A detached ADU is exactly what it sounds like: a standalone secondary home built in your backyard (or side yard), completely separate from your main house. It has its own entrance, kitchen, bathroom, bedroom(s), and living area — basically a full little house on your lot. People also call them backyard ADUs, standalone ADUs, or sometimes just “backyard cottages” because they usually look like small, cozy homes.

In California, the state law (Government Code § 65852.2) and the HCD rules treat detached ADUs the same, no matter what you call them. Sacramento County and the City of Sacramento follow the state guidelines with only small local differences, so if your property qualifies (and most single-family lots do), you can build one without too much drama.

I’ve seen a lot of these go up around here — some families in Elk Grove or Roseville wanted privacy for parents, others in Natomas or Rancho Cordova needed space for kids, and a few in Fair Oaks or Carmichael did it for rental income. The detached style is popular because it feels like a real separate home, not just an add-on.

What Makes a Detached ADU Different from Other Types

People get confused between detached, attached, and garage conversions — here’s the simple breakdown:

• Detached ADU (backyard/standalone unit) — Built separately from the main house. Full independence, own utilities, own entrance. Usually the most expensive because it’s a completely new structure.

• Attached ADU — Connected to your main house (shared wall). Easier access, lower cost, but less privacy.

• Garage Conversion — Turn your existing garage into a living space. Cheapest and fastest, but you lose garage parking.

If you want that true “separate home” feel for family or renters, detached is usually the way to go.

For real examples of detached layouts that fit Sacramento yards, take a look at our ADU models — a lot of them are standalone designs people love.

Get Detached ADU Quote

Curious what a standalone/backyard ADU would cost on your lot? Call us, we’ll give you a straight, realistic number based on your yard and needs, no pressure.

Typical Detached ADU Cost in Sacramento (2026)

Real numbers families are paying right now for a detached ADU in the Sacramento area:

• Small detached (400–600 sq ft) — $250,000 to $325,000 One bedroom, basic kitchen/bath — great for parents or starter rental.

• Mid-size detached (600–900 sq ft) — $300,000 to $375,000. One or two bedrooms, open living space — popular for multigenerational setups.

• Larger detached (900–1,200 sq ft) — $350,000 to $400,000+ Two bedrooms + office/guest — best for longer-term rentals or bigger families.

Most detached ADUs in Sacramento are built with practical mid-range finishes to stay within budget.

These are mid-range finishes — nothing fancy, but solid quality. The state max is 1,200 sq ft for detached units on most lots, and going bigger usually isn’t allowed.

A friend of mine in Roseville built a 700 sq ft detached unit for his mom — he kept it simple with standard cabinets and flooring, and it came in around $320k. Now she’s happy, and he’s got a rental option when she doesn’t need it.

For a quick sense of your own numbers, Result Construction has a custom ADU Calculator on their site — just put in square feet and your city, and it gives a realistic range.

Start My Detached ADU Project

If a standalone backyard unit sounds like what you need, call us & we’ll help you figure out what fits your yard and get a plan going.

What Drives the Cost of a Detached ADU

Here’s what actually moves the price up or down:

• Size — Every extra 100 sq ft adds roughly $25k–$40k.

• Site Prep & Utilities — Flat, easy-access lots save money; sloped yards or long utility runs (common in Woodland or Lincoln) can add $30k–$60k.

• Finishes — Mid-range (laminate counters, vinyl floors) vs. upgrades (hardwood, quartz, smart features) can swing $40k–$80k.

• Permits & Fees — $5k–$15k; pre-approved plans cut this in half.

• Contractor — A local specialist avoids change orders; general contractors often add surprises.

One family in Citrus Heights had a flat lot and used pre-approved plans — saved $45k compared to a neighbor who did custom on a sloped yard.

Get Detached ADU Quote

Want to know what a detached ADU would cost on your specific property? Call us— we’ll look at your yard and give you a clear, honest estimate.

For more on the full build process (including how to avoid cost surprises), check our guide on how to build an ADU.

Frequently Asked Questions

1. What is a detached ADU?

A detached ADU is a standalone secondary home built separate from your main house — usually in the backyard — with its own entrance, kitchen, bath, and sleeping area.

2. How much does a detached ADU cost in Sacramento?

Typical range is $250,000–$400,000 in 2026, depending on size (400–1,200 sq ft), finishes, and site conditions.

3. What’s the difference between detached and attached ADUs?

Detached is fully separate (more privacy, higher cost); attached shares a wall with the main house (easier access, lower cost).

4. Can I build a detached ADU on my property in Sacramento?

Yes — most single-family lots qualify in 2026, with 4-foot side/rear setbacks and no owner-occupancy requirement for most new units.

5. How do I get started with a detached ADU?

Check eligibility, explore designs, and get quotes. We’re happy to help with a free conversation to see what works for your yard.