How many ADUs can I build?

The floor is at least one ADU and at least one junior ADU. That is the minimum Los Angeles has to permit and it is not a quota: a city cannot write a standard that gets you below it.

Above the floor sits the third unit, and it is confirmed rather than folklore. HCD's own ADU Handbook, read with Government Code 66323, supports combining the state-law options in qualifying circumstances: one converted ADU, one detached ADU and one junior ADU on a single-family lot. This page used to say that reading was unchecked. It has now been checked, and it is what the attorney review confirmed on September 30, 2026.

What it is not is a license to build any three. Three is a count of units, and each of the three is a separate statutory pathway carrying its own requirements: the converted unit needs existing space to convert, the junior unit has to come out of the primary dwelling and brings an owner-occupancy condition with it, and the detached unit has its own size and setback rules. A lot with nothing to convert does not get the converted unit by arithmetic. Confirm the combination for your own lot with LA City Planning before you draw it.

The junior unit is the one with a condition attached, and it catches people: where a junior ADU shares sanitation with the house, the owner has to live in either the house or the junior unit. Nothing like that applies to the full ADU beside it.

The conversions and the detached units are not one allowance with two flavors. They run alongside each other, and reading them as a single cap is how owners of small buildings talk themselves out of a unit they are entitled to.

Conversions apply to space that is not currently livable: storage rooms, boiler rooms, passageways, attached garages. Twenty-five percent of the existing units, and never fewer than one, so even a duplex gets one. Detached units are separate and go up to the lesser of eight or the number of units already there.

Units created by converting existing space carry no parking requirement at all, which is often what makes the arithmetic work on a lot with no room to add spaces. For anything else the cap is one space per unit or per bedroom, whichever is less, and even that falls away where any one of six exemptions applies.

Being allowed three units and being able to fit three units are different findings, and only the first one is a legal question. Setbacks, height and the footprint already on the lot decide the second, and they are covered on the ADU size and height limits page.

It also does not settle what the city can require along the way. The counts come from the state, and so does the floor underneath every standard applied to them: what the city cannot deny you is the other half of the answer.