The Planning and Transportation Commission on Wednesday struggled to answer this question and, despite general support for the idea of promoting more second-dwelling units, agreed that more information is needed. Specifically, commissioners worried about the prospect of people building these units and then, rather then renting them out, using them as home offices or startup spaces.

These days, as the city is looking to relax these rules and encourage more affordable housing , the main question that officials are struggling with is: Which of these regulations should be relaxed or eliminated?

For most homeowners these restrictions make the construction of such units effectively impossible, thanks to regulations that require homeowners to provide parking for these dwellings and minimum-lot-size requirements that make many properties simply ineligible for adding such units.

Most commissioners, much like the City Council, agreed that it would be beneficial to relax existing regulations on these dwellings, also known as "accessory-dwelling units" or "granny units."

For some in Palo Alto, "second-dwelling units" represent one of the easiest and most cost-effective ways for addressing the city's affordable-housing crisis. But as the Planning and Transportation Commission considered on Wednesday ways to ease restrictions for these units, some members remained very concerned about the unintended consequences of any possible changes.

The effort to encourage more second-dwelling units was prompted by an October 2015 memo from Vice Mayor Greg Scharff and Councilmen Greg Schmid and Cory Wolbach, which made the case for encouraging more second-dwelling units while "minimizing impacts on community character." The memo also called for the city to consider ways to bring existing second-dwelling units into code compliance.

"We want to know if we're going to accomplish the goals of creating affordable housing or whether we'll just create a lot of Airbnb opportunities," Waldfogel said.

That concerned was shared by Commissioner Asher Waldfogel, who said he would support encouraging such units, but only if the city can make sure they are used for actual housing and not short-term rentals.

"If the public walks away with the fear that neighbors are going to open up startups in ADUs (accessory-dwelling units), that's going to result in some political opposition to this notion of creating additional housing," Alcheck said.

"I think this is kind of a political issue of interest to neighbors," Summa said. "I do not believe relaxing standards for ADUs should be used as a workaround to diminish the quality of R-1 zoning."

Some commissioners, including Alcheck, argued that the survey is unnecessary, given the council's direction and a desire to come up with a proposal by the end of this year. But Doria Summa, president of the College Terrace Residents Association, supported staff's approach and said that the survey would be a useful way to foster community outreach on this topic. She also warned against easing the regulations in a way that would have a negative effect on homes in the city's single-family zones (R-1).

In the past, however, efforts to ease restrictions on these units were met with criticism by neighbors who feared that allowing more second-dwelling units will only worsen traffic and parking congestion. The commission agreed Wednesday that it is critical for the city to be sensitive to these issues. To underscore that fact, the city plans to conduct two surveys to gauge community sentiment and raise awareness of this effort.

The memo notes that the city's "housing crisis and aging population have led many residents to call for a renewed discussion of this topic and timely, appropriate action" and cites to the fact that Palo Alto has, by some measures, the highest median rents in the country.

"However we do it, whatever regulations we change, from the user's perspective, from the neighborhood's perspective and from the citizen's perspective, the change should not be negative," Gardias said. "Otherwise, it would backfire on all that staff work."

According to planning staff, this minimum-lot-size requirement is higher in Palo Alto than in surrounding jurisdictions. In R-1 zones, for example, lots need to be at least 8,100 square feet. By comparison, Santa Cruz has a minimum-lot-size requirement of 4,500 square feet (it was recently reduced from 5,000). In San Rafael, it's 5,000 square feet.

The commission didn't take any actions Wednesday but requested more "sensitivity analysis" that would help determine the effects of possible changes to the zoning code. One rule that may be revised is the minimum-lot-size requirement. Currently, of the 15,108 low-density residentially zoned lots in Palo Alto, only 3,263 meet the eligibility requirement to build a second unit.

Palo Alto cautious about encouraging second-dwelling units

Planning commissioners call for more study before relaxing any restrictions