frequently Asked Questions

1. How much will my ADU cost?

Since the size and construction of each ADU will
differ, it is impossible to estimate the cost of your
ADU. The cost per-square-foot of an ADU is
likely to be the same as any other new residential
construction; builders and architects can give you
rough estimates.

2. How do I pay for my ADU?

There are a number of ways to pay for the
construction of an ADU. A common way is to
borrow from a home equity line of credit if you
have equity in your existing house. Other ways
can be more complicated:

1.) You could refinance
your existing mortgage to take out a larger loan
to provide cash for ADU construction (this will
require equity in the home);

2.) You may be able
to obtain a private construction loan to build
the ADU and refinance the loan with a new
mortgage when construction is complete. You
should start by talking to the bank that holds
your current mortgage.

3. How do I tell if I’m near a transit?

Many lots in LA are within a half-mile of transit,
so that ADU parking will not be required. The
City publishes a transit map at media.metro.net/
riding_metro/maps/images/system_map.pdf. First,
see if your lot appears to be within a half-mile
radius of a bus stop, rail station, or a dedicated
space where a shared-vehicle is parked. Second,
call the Dept. of Building and Safety to give your
property address. They can confirm whether you
need to provide parking for your ADU.

4. Can I Sell my ADU?

No, you can only sell your house and ADU
together. ADUs can be rental units or occupied
by the homeowner or family members.

5. Must the homeowner live on the property?

No, both the existing house and the ADU can be
rental units.

6. What if my current garage is in the front of the lot?

If your existing garage is at the front of your
house, in most cases you cannot convert it into
an ADU. You may be able to build an ADU
elsewhere on your property. You should check
with the Dept. of City Planning.

7. Can I legalize an unpermitted ADU lot on my lot?

Although this guidebook focuses on new construction, you may be able to get permits that will
legalize an existing rental unit on your property.
You can contact the Dept. of Building and Safety
for more information.

8. How big can I make my ADU?

There are some limits on the size of an ADU,
based on the size of your lot and existing house.
First, an attached ADU cannot be bigger than
50% of the existing house. For example, if your
existing house in 2,000 sq. ft., the attached ADU
cannot exceed 1,000 sq. ft. in size. Second, there
is a “mansionization ordinance” that usually restricts the total square footage of all structures on
a lot to 45% of total lot size. For example, if your
lot is 10,000 sq. ft., the total built area (existing
house, ADU, garage, etc.) cannot exceed 4,500
sq. ft. In addition, most ADUs cannot exceed
1200 sq. ft. The Dept. of City Planning will need
to verify the specifics related to your project.

9. My lot seems too small or unusal. Can I still build an ADU?

Almost every lot in LA is unique, so this guidebook addresses the most common conditions.
There are various types of ADU that work on different lots. For example, if a detached ADU will
not fit in your backyard, you might attach a new
unit to your current house. If the garage behind
your house is inconveniently located, you could
demolish and rebuild it with an ADU above.
Sketch your ideas as suggested in the guidebook,
and talk them over with the Dept. of Building
and Safety.

10. Is an adu subject to the Rent Stabilization Ordinence?

If you add an ADU to your home, you can
rent one or both of the units. If your home was
built before 1979, one or both of the units may
become subject to the City’s Rent Stabilization
Ordinance (RSO). To determine if an ADU
triggers the RSO on your property, call (866)-557-
7368. For more information about the RSO, visit
homeforrenters.org.