California Will Allow Two Detached ADUs on Many Single-Family Lots: What LA Homeowners Should Know About AB 956

A newly signed California law could materially change how some Los Angeles homeowners think about their backyards.

Governor Gavin Newsom signed AB 956 on September 29, 2026. Beginning January 1, 2027, the law increases the number of detached, newly constructed accessory dwelling units that local governments must ministerially approve on qualifying lots with an existing or proposed single-family home from one to two.

For Los Angeles homeowners and small investors, that is potentially significant.

It does not mean every property can suddenly support two backyard houses. Lot dimensions, fire access, utilities, building codes, height rules and other physical constraints still matter.

But the legal starting point is changing.

What does AB 956 actually change?

Under the signed legislation, a local agency must provide a ministerial pathway for two detached, new-construction ADUs on a lot with a proposed or existing single-family dwelling.

A local agency may impose a floor-area limit of no less than 800 square feet of livable space on each qualifying detached unit, along with applicable state height standards and side and rear setbacks of no more than four feet.

Ministerial approval is important because it generally means an application is reviewed against objective standards rather than going through a discretionary public-hearing process.

That can make the entitlement question more predictable. Construction itself is still another matter.

When does the new two-ADU rule begin?

AB 956 was signed September 29 and is expected to take effect January 1, 2027.

That date matters if you are considering a project now.

I would not assume that an application submitted under today's rules automatically receives the benefit of the new law before it becomes effective.

Anyone considering a project around the transition should verify the applicable filing rules with the local permitting agency and appropriate professionals.

Can every Los Angeles homeowner build two ADUs?

No.

State authorization is only one part of feasibility.

A property still has to physically accommodate the units.

I would want to evaluate lot width and depth, existing structures, setbacks, utility connections, sewer capacity, grading, fire access, trees, easements and the location of the existing house before assuming two units make sense.

A large flat lot with a house near the front can present a very different opportunity from a narrow hillside parcel where the existing house already consumes much of the buildable area.

Legal capacity and practical capacity are not the same thing.

Could each detached ADU be 800 square feet?

The new statute allows local agencies to impose a total floor-area limitation of not less than 800 square feet of livable space on qualifying detached ADUs under this pathway.

That creates an interesting planning question.

Two 800-square-foot units could potentially create 1,600 square feet of additional residential space on the right property.

But homeowners should not start with the maximum theoretical square footage. Start with the site.

Sometimes one well-designed larger unit may be more practical than two separate structures. On another property, two smaller units may make sense.

The best configuration depends on the lot and the owner's objective.

Can I build two detached ADUs plus a JADU?

Do not assume that you can.

AB 956 specifically says a local agency is not required to ministerially approve a junior accessory dwelling unit on a lot where two detached new-construction ADUs have been built.

That distinction is important because homeowners may see the new rule and begin adding every unit type allowed under different sections of ADU law.

The rules do not necessarily stack indefinitely.

Before designing a project around several unit types, confirm the exact combination permitted on the property.

Why could this matter so much in Los Angeles?

Land is expensive.

That means a large portion of a Los Angeles property's value can sit in the lot itself.

If state law allows a homeowner to create additional legal housing on land already owned, the economics can be very different from purchasing another parcel.

That does not mean an ADU is automatically profitable.

Construction costs, financing, utilities, insurance, taxes, maintenance, vacancy and achievable rent all have to be considered.

But the ability to spread land cost across additional units can create opportunities that would be difficult to reproduce through a separate acquisition.

Could two ADUs work as rentals?

Potentially.

State law requires rentals of ADUs created under this section to be for terms longer than 30 days.

For an investor-minded homeowner, the relevant calculation is therefore not simply: How much rent could two units produce?

I would calculate the total project cost, financing cost, realistic long-term rents, utilities, insurance, additional maintenance, reserves and expected vacancy.

Then compare the projected return with other uses of the capital.

An ADU can be a good project and still be a poor investment if construction costs become too high.

What about multigenerational housing?

Rental income is only one use.

Two detached units could create more flexibility for families who want aging parents, adult children or extended family nearby without placing everyone under one roof.

That may be particularly useful in Los Angeles, where buying several nearby properties can be prohibitively expensive.

An owner might eventually use one unit for family and another as a rental.

The ability to change uses over time can itself be valuable.

What does AB 956 change for HOAs?

AB 956 also changes language governing restrictions on ADUs in certain planned developments.

The law broadens protections from lots zoned for single-family residential use to lots zoned to allow single-family residential use. That can extend protection to additional properties where single-family housing is permitted even if the underlying zoning is not exclusively single-family.

This does not mean every condominium owner can automatically construct an ADU.

Common-interest-development rules and property configuration remain important.

Owners in an HOA should review the exact property type and governing documents before assuming the new law applies.

Could this affect property value?

Potential development capacity can matter to buyers.

A property with room for additional legal units may appeal to investors, multigenerational households or buyers who want future rental income.

But I would not simply add the projected construction cost or theoretical rental value to a home's asking price.

A buyer still has to spend money and take on construction risk to create those units.

The better approach is to evaluate ADU potential as one component of the property's overall value.

Should sellers build the ADUs before selling?

Not necessarily.

There are at least three possible strategies.

A seller could build and stabilize the units before selling. A seller could obtain plans or permits and market a more clearly defined development opportunity. Or the seller could simply market the property's potential and let the next owner undertake the project.

Which option produces the best result depends on construction cost, timing, available capital and the buyer pool.

Spending $400,000 on a project does not guarantee the eventual sale price rises by $400,000.

What should buyers do differently in 2027?

If you are shopping for a single-family property and ADU development is part of the plan, lot utility deserves more attention.

Two homes with similar interior square footage may have very different development potential.

I would look at the position of the existing house, driveway access, backyard dimensions, topography and neighboring improvements.

A beautiful backyard is one thing. A backyard that can efficiently support additional legal housing is something else.

Frequently asked questions

What is AB 956? AB 956 is a California housing law signed September 29, 2026 that expands the state's ministerial ADU rules.

How many detached ADUs will California require cities to allow? Beginning in 2027, qualifying single-family lots can receive ministerial approval for up to two detached new-construction ADUs under the applicable state pathway.

When does AB 956 take effect? January 1, 2027.

Can I automatically build two 800-square-foot ADUs? Not automatically. The state framework allows the units, but physical site conditions, applicable building standards and other requirements still determine whether a particular design works.

Can I also add a JADU? A city is not required to approve a JADU on the same lot once two detached new-construction ADUs have been constructed under this provision.

Is this legal or investment advice? No. Property owners should confirm the current rules for their specific parcel with the appropriate city agencies and qualified legal, design, construction and financial professionals.

Paul's take

This is the type of housing law that can change how I evaluate a property.

If two houses have similar living area and similar prices but one has a flat, usable rear yard with good access and the other does not, their future flexibility may be very different.

I would not buy a property solely because two ADUs might fit.

But if rental income, multigenerational living or long-term development potential is important to the buyer, AB 956 makes lot configuration even more relevant.

For Los Angeles buyers and owners, the backyard is increasingly something that should be analyzed alongside the house.