08/28/2026
I look at a lot of multifamily ADU deals that pencil beautifully on paper and then die in month three. It is almost never the thing the owner was worried about.
Here are the three that actually kill them.
Electrical service. Number one by a wide margin. Adding four units to a fourplex means four more meters, and plenty of these buildings from the fifties and sixties are running a service that cannot carry it. That upgrade is real money and it belongs in the budget on day one, not as a surprise in month four. Get an electrician on the property before you get excited about unit count.
Fire access. Cities lost parking as a reason to say no when SB 1211 took effect, so fire is where the real review happens now. Hydrant flow, turning radius, distance from the street to the farthest new unit. If a fire truck cannot already get to the back of your lot, start there.
The drive aisle itself, separate from the parking count. You can lose backup depth or trash enclosure access without noticing and find out at plan check. I watched a clean eight unit plan drop to five over an aisle nobody measured.
The law is not on that list, and that is the point. The entitlement side of multifamily ADUs is in decent shape right now. Site conditions decide these projects, and a two hour site visit would catch most of them.