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San Diego ADU rules, Granny Flat rules and Converted Unit Rules

42_9621290_117180_BPO-117180-142The talk of the state of California right now is a better way, and hopefully a cheaper way, to build an Accessory Dwelling Unit in your backyard. The “cheaper” part is by some reduced permitting fees at the county or city level. And the state of California has recently passed some laws making the whole process easier.

Right now, as of this writing, for example, the City of San Diego is waiving its ADU 1) building permit fee, the 2) building plan check fee, and 3) the DEH site fee, whatever that is for ADU construction. Call made on 11/14/2019.

Here are the fees NOT waived:

School district fee, fire fee, water district fee, the state fee (lady on phone was not more clear), and the “green” fee.

If you’re serious about an ADU, I would not start your project thinking about the nuance of fees. There WILL be permit-related fees on top of construction costs and they’ll be different, whether you’re in an incorporated city like San Diego or in an unincorporated area of the county like Julian.

I would start by asking yourself, “What is this for?” If it’s to rent, great. That’s a plan you can implement. If it’s to house a family member, great. That’s also a plan you can implement. But if it’s to have Airbnb income, that’s a no. All ADUs in the county require a minimum of 30-days stay, so this is not a short-term rental option.

In December, I will be attending my third ADU seminar. The first two had hundreds of people in them, all older in terms of demographic (many attendees in their late 70s). They wanted information. They arrived early and with notebooks. They looked like my clients! Homeowners over 50 years old, probably sitting on some home equity, all with a nice, flat backyard. They seem to be very interested in this idea! I expect my December event to be packed, too.

One thing I have learned about the ADU (no shock here) is that the construction costs are high when you build it right and following all building codes: construction costs will be somewhere between $100K and $250K per ADU, depending on size and complexity in your build. And then building fees on top of that — not all city or county permit fees are being waived, as I said.

And I see some cottage industries springing up that I am personally a little wary of: the “ADU consultant” who charges hundreds of dollars to steer you in one way or the other, and I think some of their information is probably available to you for free from the county or your city. Be careful! They also have “buddies” in the construction industry — I smell payola! They will send you to their friends for construction. For some reason, I am suspicious of instant experts on ADUs who want to charge you tons before a shovel has even hit the ground. Be careful. No names mentioned! But they are out there. Granny flats were the old name: ADU is the new name. Be wary of all consultant experts, as some of the laws, rules and new waived fees are brand new.

Here is an article from a local construction company in San Diego on the basics of an ADU. The best part of their blog post (to me) is probably the link to the city on the permit page of the city’s website. But none of the links open in new windows, so you’ll be going back and forth.

Where I can personally help you is by letting you know what your unit could collect in rent, based on your address/zip code and the size of the ADU that you may build. For that, or to sell or buy, please give me a call or send an email.

I like ADUs a great deal, but I do think they’re ultimately for the cash rich. The link I just shared talks about financing, reverse mortgages and home equity loans. Make sure the end result is worth it.


Kimberly Dotseth


Blend Real Estate

7770 Regents Road #113-275

San Diego, CA 92122

(619) 261-1909

California DRE #01179760


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