Meet the yard
The characters in A-du Insights: a small ADU, the house in front of it, an old oak and the rest of a Los Angeles backyard. Each one carries a real rule about building an ADU.
Every Southern California lot has a back third that is usually lawn. Our Los Angeles posts tell the story of what happens there with a small cast drawn from the yard itself. None of them has a face. They act the way the real things do: blinds rise, lamps come on, a gate swings, leaves move.
Each supporting character is here because a state or city rule is about it. When one appears in a post, its rule appears with it, and every rule below was checked against its source. Tap a state under any character to see how it acts.
Leads
Pip
Eager, and a little small for its ambitions.
The ADU. Starts as a pencil line at the back of the lawn.
Blinds a third down, lantern off.
- Carries
- At 750 sq ft or less, an ADU pays no impact fees.
- Appears
- Every chapter
Big House
Gruff, set in its ways, secretly proud.
The 1924 Craftsman bungalow at the front of the lot.
Blinds a third down.
- Carries
- A junior ADU of up to 500 sq ft can go inside the main house.
- Appears
- Every chapter
The yard
Old Oak
Slow, wise, and does not move for anyone.
A coast live oak. The oldest thing on the lot.
Still.
- Carries
- The City of LA protects native oaks, sycamores, black walnuts and bays. Removing one, or damaging its roots, needs a permit.
- Appears
- Chapters 1, 4 and 8
The Bins
The chorus. Lids lift when something happens.
Black, blue and green, the three LA bins beside Big House.
Lids closed, in a line.
- Carries
- No rule. The dry humor, and three more arrive when someone moves in.
- Appears
- Most chapters
The Side Gate
Squeaks. Proud of its new job as the tenant's front door.
The cedar gate in the side yard beside Big House.
Closed, post light off.
- Carries
- Tenants come in from the side yard, along a poured concrete path.
- Appears
- Chapters 6 and 7
Sunny
The solar panels. Last to arrive, brightest in the yard.
The solar array on Pip's roof.
Drawn as part of Pip's lit state.
- Carries
- New detached ADUs generally need solar under the state Energy Code; attached units and conversions generally do not.
- Appears
- Chapter 6
The Meter
Lives on Big House's wall. Nervous about sharing.
The utility meter on Big House's side wall.
Drawn as part of Big House.
- Carries
- A new ADU's connection fee must be proportional to its size or plumbing fixtures; one built from existing space is not charged as a new use.
- Appears
- Chapter 6
The street
Hydrant
A stickler. Checks everyone's paperwork.
The fire hydrant at the curb in front of Big House.
Caps on, chain slack.
- Carries
- An ADU cannot be required to have fire sprinklers if the main house is not, and building one cannot trigger them for the main house.
- Appears
- Its Yard Deck card
The Mailboxes
One, and later two.
Big House's mailbox, and later a small new one finished to match Pip.
Big House alone.
- Carries
- No rule. The second mailbox says someone moved in, without showing a person.
- Appears
- Chapter 7
The Bus
Passes the corner. Never stops for long.
A city bus at the end of the block, in generic livery.
Cream with a navy stripe.
- Carries
- No parking can be required for an ADU within a half mile walk of public transit.
- Appears
- Chapter 8
The Neighbors
Skeptical, then curious, then next.
A Spanish bungalow and a mid-century ranch on either side of Big House.
Every blind down.
- Carries
- ADUs were about 4 in 10 new homes in LA County in 2025 (USC Lusk Center).
- Appears
- Chapters 1 and 8
Garage
Tidy, with bigger plans.
A detached two-car garage on the lot next door. Never set dressing.
Door down, coach light off.
- Carries
- A city cannot require the lost parking to be replaced when a garage becomes an ADU.
- Appears
- Its own spin-off
City Hall
The Stamp
Brief, formal, and on a clock.
A rubber stamp on a permit counter. It stands in for the city.
Inked and waiting.
- Carries
- A city has 60 days to act on a complete ADU application, or it is deemed approved.
- Appears
- Chapter 5
The Yard Deck
One card for each character that carries a rule. The front has one number; the back says what the rule does and what it means in your yard. The rarity line is information: State law applies in every California city, City rule applies in the City of Los Angeles, and Local option applies only where a city has opted in.
Where they show up
In a post, the cast appears in a handful of figures. A test fit drawn in plan, the way an architect reads a lot:
Will it fit?
Test fit · plan view
50 by 120 ft lot. A 750 sq ft plan in the back third, clear of the oak, with a path in from the side yard.
Illustration, not a real property. A site-specific test fit checks the real lot, its zoning and its overlays.
The Backyard Census in motion, one dot for a handful of ADU permits issued, year by year:
Hidden city
The top 20 LA neighborhoods: 15,416 ADU permits issued since 2020. One dot is 43 permits; 2026 in pink, through July.
Dot positions are illustrative. Source: LADBS permits, LA City Open Data. Issued Jan 2020 to Jul 2026. Pulled Jul 30, 2026.
| Year | Permits issued |
|---|---|
| 2020 | 1499 |
| 2021 | 1939 |
| 2022 | 2749 |
| 2023 | 2443 |
| 2024 | 2512 |
| 2025 | 2733 |
| 2026 (through July) | 1541 |
And the one square foot that changes what an ADU pays:
One square foot
What changes between a 750 and a 751 sq ft ADU.
| Fee | 750 sq ft | 751 sq ft |
|---|---|---|
| Plan check and building permit | Apply | Apply |
| Impact fees | None | Proportional to the ADU's size relative to the main house |
| School fees | Apply (over 500 sq ft) | Apply (over 500 sq ft) |
| Utility connection, new construction | Proportional to size or fixtures | Proportional to size or fixtures |
Gov. Code 66311.5 as amended in 2025; school fees under Education Code 17620 as amended by SB 543. Checked Sep 2026.
See the dollar figures for your cityWhy only Los Angeles
The rules these characters carry are California rules, and some belong to the City of Los Angeles alone. So the cast appears on our Los Angeles posts and the Census Bulletins, and stays out of posts about other markets, where the same drawing would carry the wrong rule.
Want to know what fits behind your house? Start a free test fit, or read the posts on ADU rules.