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Navigating Granny Flat Laws in California: What You Need to Know
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Navigating Granny Flat Laws in California: What You Need to Know

|Nov 22, 2023

The golden state of California, home to limitless opportunities, is at the forefront of a housing revolution due to its new granny flat laws. The state’s not-so-secret solution to the housing crisis and the need for more affordable housing is the construction of prefab ADU in California. Think of the possibilities if you transformed your single-family house into a duplex or your garage into a relaxing retreat.

Since it's now simpler than ever to construct a granny flat, we'll review the updated granny flat laws California below.

What Is a Granny Flat House?

A granny flat, sometimes known as an “accessory dwelling unit,” is a structure that is constructed on the same lot as the primary residence. Typically accommodating little more than two people, these dwellings stand alone on the property of a single-family house. The term “granny flat” was coined to describe these types of homes since they are commonly used to house adults/grandparents.

Some granny flats are custom-made, giving you complete control over every detail, while others are mass-produced and can even be assembled from flat-packed modules. A granny flat, in its simplest form, is an additional, smaller dwelling on your land.

There are several advantages to owning such a property, such as:

  • An affordable residence.
  • It provides a wonderful option for retaining family elders in close proximity.
  • Less upkeep for smaller properties.
  • Provide additional rental income at reduced construction costs.

What Is a Granny Flat House?

Granny Flat Laws in California

California has passed a series of rules that make it easier to construct granny flats on single-family lots in response to the state’s severe housing scarcity.

The state of California passed a sweeping law in January 2017 that makes it significantly easier to construct a granny flat. The California granny flat building regulations get rid of the biggest roadblocks to the construction of such dwellings.

So What Did The California Granny Flat Laws Actually Do?

The new granny flat building regulations nullified all previous municipal regulations and replaced them with reasonable state requirements and ADU grants in California.

We’ll discuss the revised granny flat laws California below;

1. Conversion of a Single-Family House

Now, you can add a second rental unit on any prefab ADU in Southern California that already has a single-family dwelling. This shifts the playing field since it allows people to convert single-family homes into multi-family dwellings.

Conversion of a Single-Family House

2. Zoning Regulations

Granny flat zoning laws and restrictions may be different from one municipality or county to the next. However, certain granny flat building regulations are supposed to be legalized by state legislation in California.

3. Maximum Size

Types of ADUs and local building codes determine their sizes according to granny flat rules. A detached structure might be as little as 150 square feet or as large as 1,200 square feet, depending on the homeowner's needs. However, regulations for granny flats with attached garages may vary. Junior ADUs are secondary dwelling units that are attached to and part of a single-family home.

Maximum Size

4. Parking Requirements

If an existing permanent space can be converted, or if the location is within a half mile of public transportation, then no additional parking is needed.

According to granny flat laws in California, parking is no longer restricted to a specific area of the driveway but can instead be placed anywhere on the grass.

5. Setback Requirements

Permanent structures, such as a garage, do not need to be set back from the boundary of the land. Setbacks to the side and rear above an existing garage cannot exceed five feet.

6. Building and Safety Codes

Granny flat law, California, mandates that granny houses adhere to all applicable local and state safety regulations. Fire, electrical, and plumbing codes are all included in this code.

Building and Safety Codes

7. Utility Requirements

Fees should be proportional to the scale of development; therefore, utilities, water, and sewer cannot be counted as a new residential use connection when calculating impact fees. You may expect to save about $20,000 with this granny flat rule.

8. Kitchen Requirements

Most jurisdictions stipulate that granny flats meant for human occupancy must include a kitchen. It need not be as large as a regular kitchen; most kitchen sizes are flexible, and a small one is fine for code compliance.

9. Permits

If you live inside the city or town lines and your government has a building and zoning department, you will most likely need a permit. Inspections and reviews of construction plans are common parts of this procedure.

Conclusively, any municipality may choose to substitute the state legislation with its own locally crafted ordinance if it chooses. This opens the door for each municipality to give the new granny flat laws, California, its own unique twist. For instance, they can forbid short-term rentals, require owner occupation, or set minimum and maximum building sizes.

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Frequently Asked Questions (FAQs)

Who is eligible to build a granny flat?

California has made it much simpler to legalize extra housing units, but not every house is built to accommodate them, and not every landlord is prepared to take on renters. So, who can actually construct one?

An excellent first step is to research state and municipal regulations. Find out whether there are any construction costs or parking requirements for prefab homes in California in your area. Unless the ancillary dwelling unit is located near public transportation, a minimum of one parking space is required per San Diego County law. In some areas, you can even obtain authorized floor designs for granny flats ahead of time, simplifying the approval process and making it easier to build one.

How does a granny flat add value to your property?

If you ever decide to sell your home, having a granny flat attached to it will increase its selling price because of the extra living space it provides.

Additionally, container homes in California can function as rental units. These individual units are ideal for renters who are on a tight budget, who value simplicity in their daily lives, or who don't want a large living area (like a student).

How does a granny flat add value to your property


Whether your granny flat is for rental revenue, to shelter family members, or age in place, there are several factors to think about before legally constructing your prefab ADU.

We hope that the information provided above about granny flat laws, California, is helpful in building your new home addition.

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