A split St. Paul City Council on Wednesday approved a set of sweeping changes to its zoning code that allow duplexes, triplexes and townhomes to be built throughout the city.

For decades, nearly half the land in St. Paul was restricted to single-family homes. Now, up to six housing units will be allowed in almost every neighborhood on lots of sufficient size.

The council voted 4-3 to pass the changes, with Council Members Jane Prince, Chris Tolbert and Russel Balenger opposing the measure.

The changes will take effect 30 days after the ordinance is signed by Mayor Melvin Carter, who in a statement called the vote "a big step toward achieving the goals outlined in our 2040 Comprehensive Plan."

"With these changes, we are investing in the housing supply and expanding affordable housing and wealth-building opportunities for all of our residents," Carter said.

Though the St. Paul policy has been in the works for more than two years, it was passed with relatively little fanfare — a stark contrast to the bitter debates over Minneapolis' 2040 Plan, which in 2018 opened the door for triplexes throughout the city.

Supporters of the policy are hoping increased density will help alleviate St. Paul's housing shortage, eventually leading to more affordable options — particularly for low-income families and people of color, who were historically segregated as a result of zoning policies.

They also said it will give residents more housing choices to suit a variety of lifestyles.

"To me, this is about helping our community grow, and grow in a sustainable way all throughout our neighborhoods," Council Member Mitra Jalali said.

Prince and Tolbert said they worry the changes go too far, echoing concerns expressed by residents who fear the new rules will lead to the demolition of smaller, more affordable homes to make way for multi-unit developments.

"I think it creates a huge incentive for outside investors buying up single-family homes, renting them at higher rates, reducing affordable housing and homeownership opportunities," Prince said.

Minneapolis' first-in-the-nation reform has not yet led to a deluge of duplexes and triplexes, and subsequent reforms in the suburbs have spurred little development. Officials have noted that financing and building code requirements can create challenges for smaller projects, which may not be able to produce a standard market-rate return.

Still, advocates of St. Paul's policy said that over time, they believe the changes will boost the tax base while improving sustainability, walkability and vibrancy.

"This is the right thing to do on so many levels," Council Member Rebecca Noecker said. "I'm glad that staff were actually a little bit more ambitious with some of the goals that we originally laid out, because I think we need to err on the side of being more aggressive with all of those benefits."

Opponents have said they think the changes will lead to a loss of neighborhood character, property values, green space and privacy, while increasing congestion and parking problems.

"I do think there are much easier and wiser policy choices that this council could make any day, if it's really about creating more housing units in the city of St. Paul," said Tolbert, adding that he believes the benefits are outweighed by the negative effects the zoning changes will have on the character and feel of neighborhoods.

The changes adjust dimensional requirements — such as setbacks, building and lot-size standards — to give developers more flexibility to build multi-unit housing without having to seek variances.

Under the new ordinance, fourplexes can be built throughout the city except for a portion of the Highwood area, a hilly part of the Mississippi River bluff on the East Side that isn't consistently served by city sewer or water services. Five-unit buildings are allowed by major transit corridors.

Developers can build six-unit properties if they meet the city's "density bonus" requirements, which incentivize builders to convert existing residential properties or add units with three bedrooms or income restrictions.

Additional amendments aim to make it easier to split lots and build accessory dwelling units — smaller, secondary housing units that would share a lot with a single-family home.

Future tweaks to the code may be on the horizon. The denser zoning district currently applies to areas within an eighth of a mile of major transit junctures, but Jalali and Council Member Nelsie Yang have expressed interest in bumping that radius to a quarter-mile.

In the coming weeks, city staffers also need to update site plan review processes to reflect the new rules.