CSLB officials: verify licenses, contracts and inspections before building an ADU

Catherine White, chief of public affairs for the Contractors State License Board (CSLB), and Steve Panelli, a CSLB board member and chief plumbing inspector for the San Francisco Department of Building and Inspection, advised homeowners to take several steps to protect themselves before building an accessory dwelling unit (ADU).

Why it matters: ADUs can add living space or rental income but also involve planning, permitting and construction risks. Officials said checking contractor credentials and ensuring permits and inspections are complete can reduce the risk of incomplete work or fraud.

Panelli said the first practical step is to confirm whether a property can accommodate the kind of ADU a homeowner wants. "Depending on the type of ADU you would like to provide or build... if you only have 500 square feet in the backyard, you're more than likely not gonna be able to build one," Panelli said, noting size, egress and fire-safety requirements affect feasibility.

Both officials emphasized checking contractor credentials. White identified herself as CSLB’s chief of public affairs and pointed listeners to the board's website; Panelli urged homeowners to "go to... cslb.ca.gov and check my license, their license, and see the license of the person that's trying to build your ADU or manufacture the units." The CSLB website, he said, lists contracts and licensing information and shows whether complaints are pending.

On contracting and payments, Panelli recommended written contracts and multiple bids. "I would definitely want to see something in writing. I want something in a contract," he said. He advised getting more than one bid even if contractors are scarce and checking reviews and complaint histories. On upfront payments he recommended modest deposits, saying, "If you look around hard enough, you'll find more than one person to give you a bid... Two is money upfront... I mean, it's a thousand dollars upfront. I think, you know, that's a down payment." He added, "Okay. You know, that's about as maximum you should do. I wouldn't go any higher than that."

Panelli also urged homeowners to confirm that contracts cover the full scope of work, including foundation, electrical, plumbing and mechanical systems so the finished unit is habitable. "You want to make sure whatever you're purchasing, you make sure everything is encompassed in that contract," he said, warning that partial work can leave homeowners with an unconnected structure.

Finally, both officials stressed that final payment should follow sign-off on required permits and inspections. Panelli used a hypothetical to illustrate the risk: "Last thing you wanna do is give your final payment, let's just say a $100,000 out of a $300,000 job and find out that the water doesn't run, electricity doesn't work... You wanna make sure you had your final inspections done to plumbing, electrical, building, fire... and everything is working before that final end is done."

Resources and next steps: the officials directed homeowners to the Contractors State License Board website, cslb.ca.gov, to check licenses and complaint records and to local building departments for permit and inspection requirements.