Building an ADU in San Diego After Your Zone Lost the Bonus Program

00:00BaileySo the city of San Diego just quietly eliminated the A DU Home Density Bonus Program from a handful of single family zones throughout the city, and most property owners in these neighborhoods have no idea.

They just lost access. So, Sean, for people who aren't familiar, what is the A DU Home Density Bonus Program and why were so many San Diego property owners excited about it?

00:28Sean CanningWell, thanks for the introduction, Bailey. So the A DU Home Density Bonus Program also referred to as the a DU Bonus Program. Um, at least previously it was referred to that it's a. Density bonus program where after you build your buy right ADUs that the state affords you, you can then continue to build ADUs.

The next one would be affordable. And then after that, you get one that's market rate, and then you can build an affordable one and then a market rate one. So this is a pretty powerful density bonus, which could allow you to build more than two ADUs on your lot. And in some cases, you know as many as. 30 or 40, depending on the size of your lot.

Now, a couple important things to understand, a couple important constraints here. You cannot break through the maximum floor area ratio of the base zone. So if you're doing this in a single family zone, you're gonna be limited by the. Uh, floor area ratio, which is lower in single family zones. You also still have the same setbacks as ADUs.

So in no ca in no case can you go closer to your property lines than you could if you were just building one a DU. Um, and in the single family zones, oftentimes ADUs are now limited to. Two stories. Um, so that's the scenario. That's kind of the background of the program. The program's been very controversial.

It only applies in the city of San Diego. So I, I do wanna state that, like you can't do this in Carlsbad, um, or Chula Vista. You can only do this in the city of San Diego. So the reason this has been so controversial is because you can use some single family zones that were basically zoned for a single family home.

Oftentimes you can build, uh, two ADUs on those lots depending on how you. Work, work the state a DU program. But using the city of San Diego's a DU bonus program, a lot of times you can now build four ADUs or five ADUs, and that's created a lot of controversy because obviously we need more housing, but people in these single family zones are not expecting this type of density.

Um, now this was a very interesting topic to research because zoning historically has been used to redline neighborhoods. It's been used to keep minorities in certain areas and allow for property value to increase in other neighborhoods by selectively limiting density. So let me do a quick screen share

here.

So the zones where these are banned. Are going to be these light yellow zones, and then we can cross reference this with Google Maps of San Diego and we can determine what neighborhoods these are. So let's get started figuring out which zones are essentially red lining developments here, redlining dense developments.

Okay, so first, let's take a look at this one. What neighborhood is that? Well, we can zoom in here. That's Encanto. So Encanto is not particularly a very wealthy area. It's kind of somewhere in the middle. But it's interesting that Encanto is one of these neighborhoods because Encanto just publicly had a big dispute over a footnote that was in the municipal code, which would've actually worked in their best interest and allowed them to subdivide lots.

Smaller than the existing lots. Now, this was pre presented to City Council as a racist, um, footnote, when in fact it was actually the opposite. It would've given these homeowners more opportunity. But now based on this new regulation, I'm showing you, this area right here in Encanto is banned from using the Home Density Bonus Program.

Okay, now let's zoom out a little bit. And scroll up and see if we can find some more neighborhoods. The next one is probably not gonna be a big surprise. Look at all this light yellow over here. And what neighborhood is that? Well, if we scroll,

04:22Baileyone. That is La Jolla.

04:24Sean CanningThat's La Jolla, right? So they're starting to become a pattern here.

Where some of these more wealthy neighborhoods are banning this program because they don't want density, and this is like 2026 redlining all over again. Why shouldn't there be an equitable approach to using this program and an equitable approach to providing affordable housing? Well, you can't do it in La Jolla.

Now let's, let's zoom out a little bit more and let's go over here, see what we can find. Okay, so over here, let's take a look at this. What neighborhoods are these? So we'll zoom in here and we'll just take one road here. Okay. Collette Way. So let's see what Collette Way is.

Okay, zooming in over here. And we can see that this neighborhood is considered Tiara Santa. So this is a wealthy neighborhood, and if we look here, look at how much light yellow is in this area. Basically the majority of Tiara Santa is banning this type of density using the A DU Home Density Bonus Program.

So let's continue to explore here and see what else we can find. I believe this will populate. It's a city website, so bear with it.

05:40Baileyjust to clarify, it's people in these areas can't take advantage of the Home Density bonus program, but could they still develop which I believe every lot usually about one, maybe two by default.

05:56Sean CanningYes, so these neighborhoods can still use the state a d regulations and the city and these communities cannot do anything about that because the state has made it very clear. But interestingly enough. These neighborhoods will never be able to reach the density that other neighborhoods have. So is that by accident or is it by design?

And I guess that's what we're debating right now. Okay. Let's take a look at some of these other neighborhoods. So I'm gonna kind of zoom out here. Hopefully this loads.

Okay, so we looked at these ones already. Let's come over here.

Now we're gonna be north of La Jolla,

so all this yellow. You can do this, all this brown. You can use the A DU Home Density Bonus Program. This is interesting. There's a little pocket over here and a little pocket over here. So let's figure out what these neighborhoods are. So if I zoom in, the street names should populate and we'll use this one Aspendale drive

I.

Okay. So for some reason this pocket is barred from using this program. Let's take a look at the size of these homes. They seem like pretty large homes. I would expect this to be a pretty well-to-do neighborhood. And if we zoom out here, what is the name of this neighborhood? Mo Scripps Highlands, one of the more wealthy neighborhoods in San Diego.

So you can see the trends start to develop. Uh, when we were over here, we noticed that there was another pocket of zoning that prevents this. Let's see where that was. So over here, we can't do this in the RS one eight and here's the RS one nine. So just uh, east of Poron Road. So let's see if we can find where that is.

I'm gonna come over here. Poron Road, just east. So it's going to be this neighborhood over here, which is also part of Scripps Ranch Fair Fairbrook Estates. So you can start to see a trend develop Bailey. What do you think?

07:40BaileyYeah, I mean, you can tell most of these places are wealthy neighborhoods just based on the name of the neighborhood.

07:47Sean CanningLet's, uh, let's do one more just to see if the trend continues here. I'm gonna zoom out a little bit. I,

and we'll start to climb a little bit more north.

As the city website populates.

So again, we're looking for those pale yellow neighborhoods. Here's one HETO Court.

08:01BaileySo, maybe you don't even know this, but what is the, how does this actually end up happening in practice? Like is it just going to like the local community town hall type events to for this? How does it actually end up, you know, becoming into the municipal code?

08:16Sean CanningSo basically community groups would lobby or put pressure on city council, and then the code would be modified through a procedure with city council. And then they would determine, okay, we are going to take this specific zone and eliminate it from the program. So they're basically being lobbied by the communities.

And, um, some of these neighborhoods have big money behind them, and that's basically how they're able to do it. And this is part of, uh, Los Pen, mosquitoes area here. So it looks like another wealthy area. Basically all these neighborhoods up here are pretty, pretty well off. And see over here, this entire group, this entire yellow, you can do, you can use the A DU bonus program here.

So there's density permitted in these neighborhoods, but not in those light yellow neighborhoods. Let's keep going here. See if we could find one more just to drive the point home.

So you can see that the majority of San Diego does allow this, and it's very select neighborhoods that does not allow this. Okay, let's take a look at this one here. This is our Summit Trail.

I'm gonna come here and Pacific Highlands Ranch, very well off neighborhood, so I think that's enough. You can kind of get the idea of what's going on here and the pressure that's put on City Council to change this municipal code. Um.

So what do you think about this, Bailey?

09:41BaileyWell, I mean, I don't think it's necessarily good, but I do think it's predictable. I think honestly, based on all this, these neighborhoods would probably go as far as to even ban the regular A DU codes, the ability to build one or two on your lot if they could get away with it.

09:57Sean CanningYeah, um, that's probably true. I mean, a are very misunderstood. You have to. You have to think about it as an A DU is just a home. There's homes that are, I live in a home that's smaller than the maximum size of an A DU. So I live in a 800 square foot home. You could build an A DU at 1200 square feet and it's, for all intents and purposes, it's the exact same thing.

So a D are not something to be feared, but I think what people fear is more density in their neighborhoods and. I just wanna also reiterate the point. These zones that do not allow this a DU bonus program are very select zones within the constrains of the city of San Diego. I mean, you're talking about like less than 5% that are banning this program.

And then it was very interesting to actually, uh, cross-reference these zones with the neighborhoods. And then you start to. See what's going on here, which neighborhoods are banning density and which neighborhood, which neighborhoods have lobbied city council to prevent this type of development. Um, so the puzzle pieces kind of all fit here.

And, uh, I guess after doing all of the research here, ultimately, like you said, it's not a surprise, but, uh, that's the results of how zoning can affect density and how zoning can affect the city.

11:17BaileyTwo quick questions before we wrap up. Number one, what if someone already had a project in place or like in the planning stages, maybe it was in like permitting review, for example, that was going to take advantage of the A DU home bonus program. Like how would that happen for projects in flux?

11:36Sean CanningOkay, so the deadline is you basically have to get your. Project into permitting before the code changed and then your grandfathered into. The code that was in place at the time when you submitted the project, if they didn't use that as a deadline, like it would just be chaos. Um, because this code changes so often.

Um, I was using the March version of the code March, 2026, but this change actually occurred, uh, around Mid August, so it's definitely too late to get your project in in any of these neighborhoods, but you could have done it before August of 2025.

12:12BaileyGot it. Um, I guess just something for people to know in general, if, you know, they're planning a project to know when like the deadlines are in case they're looking to take advantage of, um, older regulations. And then the last question is, so in your expertise, how would you advise people who perhaps. Want to perhaps live in these neighborhoods or want to develop in them, say they were planning to take advantage of this program, they can no longer do so.

Is there anything you would suggest as a backup plan?

12:40Sean CanningWell, I mean, if you live in this neighborhood. And you were considering developing ADUs, you still do have a lot of options. You cannot build, you know, four ADUs in your lot in these neighborhoods. It's just not going to be permitted. But I would imagine if you're a homeowner in this neighborhood and you want to build an A DU for rental purposes, you could still build a detached a DU up to 1200 square feet.

You could convert your garage, which is generally a smart move, financially forward move. Um. I also work on projects where homeowners want to build a home for their children or want to build a home for their elderly parents. And the A DU fits that mold perfectly. So that's a kind of understated use of the A DU Land is so expensive right now.

Properties are so expensive right now in San Diego, but if you already own the land and. You can build an A DU for far less expensive than you can buy a new property. So you can actually use this A DU and now you can take care of your elderly parents right on your property. Um, or when your kids graduate college and you find out that because we don't have enough housing here, they actually can't afford to.

Buy anything. You could build them this a DU in the backyard. They could live there with their family. Now their kids will be close to you. To you. This is a great scenario and it's much better than them moving to Riverside or, um, you know, moving to another state.

14:06BaileyDefinitely. Yeah. And then on that note, then, would it be possible for people to build a duplex or a triplex even like, you know, build up taller and then as a, as a sneaky way to get more rental units potentially on like a small footprint?

14:23Sean CanningWell, sometimes the, it's hard to build an A DU in 2026 and make it cash flow for rental purposes, like construction cost is high materials, high fees are higher. Now for these ADUs. Um, and land is high. So it's just very difficult to build ADUs to, to cashflow for rent. Uh, in most scenarios, you're better off taking that money and investing, investing it in the stock market.

However, in some of these more well-to-do neighborhoods. Um, the amount that somebody would pay to rent them is higher, so potentially it could pencil out. In general, you're not gonna make the math work if you're doing a second floor, a DU and also you're gonna be limited in these single family zones now to two stories.

Um, so I think the neighborhoods we're discussing here. The strategy would be to build a family compound or build an a DU that could be used as a guest house, um, uh, multipurpose home office, home gym. That's what makes sense in these higher end neighborhoods. It doesn't necessarily make sense to build these to rent, uh, although in some scenarios it, it could, uh, especially like a garage conversion.

You could also take one of these large homes and split it into a duplex with half of it being an A DU. Half of it being the dwelling unit without adding any square footage. And I would suspect that would probably be a smart financial move if, um, if you're willing to live in a duplex. But I think a lot of the people who buy in these neighborhoods, they're just not looking to live in a duplex.

So the a DU really makes sense for, I think a detached a DU makes a lot more sense. Uh, you can provide a lot of privacy and respect to the occupants of a detached a DU, and. Right now we're doing ADUs as part of like a family compound, and I think of these properties that that really makes the most sense.

16:17BaileyThere's always a way to get creative with it, I think is fair to

16:19Sean CanningMm-hmm.

16:20BaileyUm, if people, I think that's a good place to leave it. If people want to get in touch with you about an A DU project, what's the best way for them to find you online?

16:28Sean CanningWell, you can go to 10 70 architecture.com. You could visit our Instagram page or you can send me an email, which is Sean, SEAN, at 1 0 7 0 architecture.com. And also, I'm curious if people wanna drop comments and. Let me know if they think this is an intentional modern day redlining process or if they think this is, uh, just chance.

I'm curious to hear what people think.

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