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What Is a Granny Flat in California? (ADU Explained)

  • Writer: Result Construction
    Result Construction
  • Dec 30, 2025
  • 5 min read


If you're a Sacramento homeowner and the phrase "granny flat" has come up while you're thinking about adding a little extra living space to your property, you're probably wondering exactly what it means, and whether it's different from an ADU. Families often start with this question when they want a quiet, private place for aging parents to stay close, a separate spot for adult kids to have independence, or even a rental unit that brings in steady income and helps with resale value down the road. Start My ADU Plan


The straightforward answer in 2026: A granny flat is simply another name for an Accessory Dwelling Unit (ADU) under California law. The state does not recognize any legal difference between the two terms. The California Department of Housing and Community Development (HCD) and local jurisdictions (including Sacramento County and the City of Sacramento) use "ADU" as the official term, but "granny flat" is one of the most popular everyday names people use, especially for detached units that feel cozy and cottage-like.


Other common names you’ll hear interchangeably include:

  • Secondary unit

  • Backyard unit

  • In-law suite

  • Cottage unit


All of them refer to the same thing: a secondary, self-contained living space on the same lot as your primary single-family home, with its own kitchen, bathroom, sleeping area, and entrance. Start My ADU Plan

The reason so many people still use "granny flat" is that it’s a warm, familiar term that’s been around for decades. But since California’s major ADU law updates began in 2016–2017 and continued through 2025–2026, the state has standardized everything under "ADU" to make the rules clear and consistent. So when someone says "I want to build a granny flat," they’re really talking about building an ADU, and the same eligibility, zoning, permitting, and cost considerations apply.


Granny Flat vs ADU: Is There Any Real Difference?

Legally, no, there is no difference. California Government Code Section 65852.2 (the main ADU law) and the HCD ADU Handbook (updated January 2025) treat all these terms as synonyms for Accessory Dwelling Units.

In practical conversation, though, people sometimes use "granny flat" to describe:

  • A detached backyard unit with a cozy, traditional cottage look

  • Smaller, simpler secondary units

  • Units specifically designed for aging parents (the original "granny" reference)

But again, the state sees no distinction. Whether you call it a granny flat, secondary unit, or backyard unit, it falls under ADU regulations in Sacramento County and the City of Sacramento.

I’ve seen this confusion firsthand many times. Families will tell me they want a "granny flat" for their parents, then get nervous when they see "ADU" on permit forms. Once they understand it’s the same thing, the stress melts away, and they can move forward confidently.


For a deeper dive into what an ADU really is, our complete guide on what an ADU in California explains it step by step. Get ADU Cost Estimate


Who Can Build a Granny Flat / ADU in Sacramento?

Most single-family properties in the 60-mile Sacramento radius qualify for a granny flat (ADU) under current 2026 rules. The state has made eligibility very broad to encourage more housing options.

Core eligibility basics:

  • You must have a primary single-family home on the lot (existing or proposed).

  • The property is zoned residential (most common R-1, R-2 zones qualify).

  • No strict minimum lot size; state law overrides many local restrictions.

  • No owner-occupancy requirement for most new ADUs (rule extended past 2025).


Local Sacramento-area notes:

  • Sacramento County, nearly all single-family lots qualify; 4-foot side/rear setbacks; pre-approved plans available.

  • City of Sacramento, Similar rules; height limits 16–25 feet for detached units.

  • Primaries (Elk Grove, Roseville, Folsom, Citrus Heights, Rancho Cordova, West Sacramento, Natomas, Carmichael, Fair Oaks), all follow state standards.

  • Secondaries (Vacaville, Davis, Woodland, Antelope, Rocklin, Lincoln, Vallejo, Antioch) , Same state overrides apply.


To confirm your property qualifies quickly, use the Sacramento County Online Map Viewer or the City’s ADU Resource Center; just enter your address.

For more on eligibility specifics, our post on can I build an ADU on my property has practical steps and tools. Get ADU Cost Estimate

Wondering what a granny flat / ADU would cost on your lot? Call us at +1 (916) 238-8240, we’ll give you a realistic number based on your size and location, no pressure.


Types of Granny Flats / ADUs You Can Build

Granny flats come in the same forms as ADUs. Here are the most common types of families that choose in our area:

  • Detached Granny Flat (Backyard Unit), Standalone cottage-style home in the backyard. Up to 1,200 sq ft; great for full privacy.

  • Attached Granny Flat, Connected to your main house; ideal for easy access to help aging parents.

  • Garage Conversion Granny Flat, Turn your existing garage into a living unit; often the fastest and most affordable.

  • JADU (Junior ADU), Smaller unit (max 500 sq ft) inside your home; perfect for compact family needs.



Many families go with detached backyard units because they feel like a true "granny flat", cozy, independent, and charming. Start My ADU Plan

For real examples of layouts that work well on Sacramento lots, check out our ADU models; there are lots of cottage-style options there.


Benefits of Building a Granny Flat / ADU

Once people realize "granny flat" is just another word for ADU, the benefits become very clear:

  • Multigenerational living, Private space for parents or kids while staying close.

  • Rental income of $1,500–$2,500/month is possible in many Sacramento neighborhoods.

  • A property value boost often adds 10–20% to resale value.

  • Aging in place keeps seniors in familiar surroundings without moving.


I’ve seen families in Fair Oaks and Carmichael turn their backyards into these units. The peace of mind it gives everyone is huge.


Ready to Explore a Granny Flat / ADU for Your Property?

Now that you know a granny flat is simply an ADU, the next step is seeing if your lot qualifies and what it would look like for your family. Start My ADU Plan

If you’re ready to explore options, Call us at +1 (916) 238-8240, and we’ll help you figure out what works best for your property and goals. Get ADU Cost Estimate 


Want a clear idea of what a granny flat / ADU might cost? Give us a call us at +1 (916) 238-8240, and we’ll give you an honest, tailored estimate.

For more on costs, check out our detailed breakdown of how much to build an ADU.


Frequently Asked Questions

1. What is a granny flat in California?

A granny flat is simply another name for an Accessory Dwelling Unit (ADU), a secondary, self-contained home on your property. Start My ADU Plan


2. Is a granny flat different from an ADU?

No, they are the same thing under California law. "Granny flat" is a popular everyday term for ADUs, especially detached backyard units.


3. Can I build a granny flat on my single-family lot in Sacramento?

Yes, most single-family lots qualify under 2026 rules, with 4-foot setbacks and no owner-occupancy requirement for most new units.


4. What are the main benefits of a granny flat / ADU?

It provides private space for family, potential rental income ($1,500–$2,500/month), and often increases property value by 10–20%.


5. How do I get started with a granny flat / ADU?

Check eligibility first, then explore designs. We’re happy to help with a free consultation to see what fits your needs. Start My ADU Plan


 
 
 

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