On Monday, the California Senate is set to vote on a bill aimed at easing the dire housing shortage by making it easier for homeowners to add a legal in-law unit within their building’s existing footprint.

SB1069 is one of several bills that would prevent cities and other jurisdictions from imposing certain requirements on property owners wanting to add a second unit. It comes at a time when many California cities are relaxing their rules in an effort to promote affordable housing in established neighborhoods near transit and job centers.

San Francisco, Oakland, Berkeley and Redwood City are among the Bay Area cities that have recently passed ordinances easing restrictions on “accessory dwelling units,” commonly called in-laws, granny flats or backyard cottages.

“This is a really easy and visible way to add places for people to live, because some people have more house than they need,” said Denise Pinkston, co-chairwoman of the Bay Area Council housing committee.

After watching TV shows about the tiny-house fad, Sharmila Kanagalingam decided last year to convert her detached garage in East Oakland into a small apartment. But when she learned that she would have had to create an additional off-street parking space, she backed off.

“That would have required us to demolish the garage and rebuild one in our backyard,” she said. “It would have taken all the lawn away.”

In January, however, Oakland approved an ordinance that waived the additional parking space requirement for secondary units located within a half-mile of a BART station or other major transit stop. “We are within a half-mile of a major bus stop, at 36th and MacArthur. Therefore there is no parking requirement for the second unit,” Kanagalingam said. That allowed her to go ahead with her plan.

At the state level, lawmakers have been trying for decades to promote the development of secondary units.

In 1982, they passed the Second Unit Law, which established a framework for local governments to enact an accessory dwelling unit ordinance. But the law had limited success, and some cities found new ways to discourage second-unit construction. In 2002, the Legislature amended that law to dismantle some barriers. The changes required cities to have a ministerial or streamlined process for approving secondary units that meet the city’s requirements. But that too has had limited success.

“The principal roadblocks to homeowners doing this legally are the high cost of permitting and some overly restrictive parking and setback requirements,” said Matt Regan, a senior vice president with the Bay Area Council.

“Say you have a standard four-bedroom, two-bath home and want to turn it into a three-bedroom, one-bath home and a one-bed, one-bath home for a college student,” Regan said. In most cities today, that would be treated like a new home, and you would have to pay fees ranging from $25,000 to $60,000, most of which are utility hookup fees, he added. If you were simply adding a new bedroom and bath, man cave or yoga studio, those fees generally would not apply.

Although the definition of a second unit varies by locale, in most places, if there is a functioning kitchen, separate entrance and no interior connection to the main home, it’s treated as a second unit.

State bills

SB1069, by Sen. Bob Wieckowski, D-Fremont, would amend the Second Unit Law again, but it would apply only to “accessory dwellings” created within the walls of the existing main house (including an unfinished basement or attic) or in an existing detached structure. It would not apply to new square footage added as an extension of the main home or to a detached cottage built from the ground up, Regan said.

Under the bill, local agencies could not impose parking requirements on an accessory dwelling if it is part of the existing primary residence, located within one-half mile of public transit or shopping, in a historic district or within one block of a car-share vehicle.

It also says accessory units “shall not be considered new residential uses for the purposes of calculating private or public utility connection fees, including water and sewer service.” Local agencies also could not require fire sprinklers in the new unit if they are not required in the existing residence.

The bill is supported by a long list of business and housing groups. Its main opponent is the California State Association of Counties.

In a letter to lawmakers, the association said the bill would place “unwarranted restrictions on local planning authority, which would create costs that could either not be recouped, or which would be passed on to the community at large.” The bill’s “prohibition on sewer and water connection fees will create practical impediments to the development of second units and, if the bill is successful in promoting the development of such second units, unfunded capital costs for sewer and water providers.”

An Assembly bill sponsored by Richard Bloom, D-Santa Monica, would make fewer changes in the Second Unit Law, but it would apply to more units, including newly constructed additions and freestanding structures. AB2299 would prohibit local agencies from imposing parking requirements on second units that are located within a half-mile of public transit or in a significant historic district. The bill is on the Assembly floor, but a vote has not been scheduled.

Another bill on the Assembly floor, AB2406, would create a category of in-law called a “junior second unit.” A junior unit must be built within an existing single-family, owner-occupied home and share an interior door with the home. It could not exceed 500 square feet and would have to include an existing bedroom and an “efficiency kitchen” with a small sink and no stove, dishwasher or disposal.

Junior units

For junior second units, cities could not require additional parking or impose water or sewer connection fees. The bill is sponsored by Tony Thurmond, D-Richmond.

For the interior connection, most people are putting in two doors, with a dead bolt on each and insulation in between, said Ellen Nicosia of Lilypad Homes, a nonprofit that is helping homeowners create junior second units.

Nicosia said that Novato, San Rafael, Fairfax and Tiburon have adopted junior second unit ordinances, while Belvedere, Richmond and unincorporated areas of Marin County are considering it. In Novato, a homeowner might pay $29,000 in fees (excluding building permit fees) for a traditional second unit, compared with about $400 for a junior second unit, she said.

City efforts

Bigger cities have taken different approaches.

Starting in April 2015, San Francisco allowed in-law units to be created in buildings undergoing voluntary or mandatory seismic retrofitting.

In July 2015, San Francisco passed ordinances allowing in-laws to be created in nonresidential space within existing buildings (such as basements or storage areas), but only in Districts Three and Eight. Those new units are subject to rent control only if the rest of the building is. Supervisor Aaron Peskin is sponsoring legislation that would allow in-law units citywide. “I don’t think land use along supervisorial lines makes sense,” he said.

Berkeley liberalized its second-unit ordinance last July. Among other things, it increased the maximum allowable size of the unit and waived a $2,000 administrative use permit. It also waived the parking space requirement for homes within a half-mile of a BART stop or a quarter-mile of a rapid-bus stop. If additional parking is required, it can be fulfilled with tandem, or front-to-back, parking of cars.

“It’s a big question mark about whether the changes in the rules will increase the number of accessory dwellings,” said Kevin Casey, whose firm, New Avenue, helps homeowners find architects and contractors to build in-law units. “Berkeley changed the rules, they were braced for a flood (of new applications), they didn’t see it.”

San Francisco has received 72 permit applications for in-law units since the seismic retrofitting legislation took effect in April of last year. Of these, 68 were for buildings undergoing retrofitting. The others, presumably, came in under the Districts Three and Eight ordinances.

In San Francisco, “they have waived a bunch of requirements, but the process is still pretty long and bureaucratic. It’s not like you can turn in your drawing and pick up a permit,” said architect Mark Hogan of OpenScope Studio.

It’s also very expensive. “People aren’t building for under $250 a square foot. It could be a lot more if you have to do excavation,” Hogan said. Homeowners “can potentially make a lot of money back in rent, but it’s a big risk.”

Santa Cruz is held up as the California city that has done the most to encourage in-law development, but even there, it’s not easy or cheap.

Toni Gardner started the process more than a year ago. She wanted to tear down a stand-alone garage and create a 640-square-foot granny unit for herself, so her son and his family could move into the main house from a trailer park in Prunedale.

“We submitted the permit request on Oct. 13. We were told it normally takes six to eight weeks,” for approval, she said. Instead, it took more than six months.

“We were initially told we could do it for $200,000,” Gardner said, “but then the fees starting coming in. The architect had to make revisions four or five times.” Then there was a $22,000 bill from the water district, more than $11,000 to widen her driveway and pave the backyard for another parking space, and a bill from the arborist to deal with a heritage tree. Now she hoping $250,000 will cover it.

Kathleen Pender is a San Francisco Chronicle columnist. Email: kpender@sfchronicle.com Twitter: @kathpender