Gov. Jared Polis on Monday signed into law two of the most significant housing bills of this year’s legislative session.

House Bill 1313 mandates local governments to change zoning to accommodate high-density transit-oriented communities. Those mandates affect just five areas in the state, mainly along the Front Range, known as metropolitan planning organizations.

The five MPOs are the Denver Regional Council of Governments, the North Front Range MPO, the Pikes Peak Area Council of Governments, the Pueblo Area Council of Governments, and the Grand Valley Metropolitan Council.

The bill exempted mountain communities or municipalities under 4,000 residents.

The bill aims to promote more affordable housing adjacent to bus routes and light rail, but not every community has that access, and there may be other barriers, such as highways and drainage systems or a lack of water to serve those housing units.

The bill requires each of the 31 municipalities in those regions to develop housing opportunity goals based on 40 units per acre adjacent to transit centers.

Because the bill preempts local government decisions on zoning, more than a dozen cities, including Aurora and Colorado Springs, and the Colorado Municipal League, opposed the measure. Local government officials also said that 40 units per acre may not be feasible.

As introduced, HB 1313 carried hefty penalties for municipalities that refuse to go along — losing their share of state transportation funding and the risk that the state might seek court injunctions to force them to comply.

But that language didn’t sit well with some House Democrats, such as Rep. Marc Snyder, D-Colorado Springs. During the bill’s final House vote, Snyder vowed to do everything he could to defeat the measure should it return to the House with that punitive language. A Senate committee immediately stripped it out, but that cost the measure the support of Sen. Julie Gonzales, D-Denver.

The bill’s mandates for municipalities, potentially violating the constitution’s language on home rule charters that allow local governments to decide on zoning, could also land the Polis administration in court.

The measure was sponsored and approved only by the legislature’s majority Democrats.

“Housing and transit go hand in hand, and with this legislation, we are saving Coloradans money and helping them live where they want, with access to what they need. Thank you to the sponsors and the broad coalition that supported these bills to create a more affordable Colorado,” Polis said Monday.

Polis signed a second housing bill Monday, one of the few that received bipartisan support, on accessory dwelling units (ADUs), also known as granny flats or casitas.

Those units, also mandated for metropolitan planning organizations, require local governments to allow the construction of ADUs on single-family home properties. House Bill 1152, however, provides several exemptions, such as if the property cannot handle more water and sewer infrastructure or is on a historic property.

On Monday, the governor called ADUs a “lower-cost option that can help increase housing choices for Coloradans.”

“Coloradans are overwhelmingly supportive of ADUs, and this legislation gives many Coloradans the freedom to build them on their property if they choose to. I appreciate the work of the bill sponsors and look forward to seeing Coloradans take advantage of this new freedom,” he said. 

Aside from the vote of its House Republican sponsor, Rep. Ron Weinberg of Loveland, the bill won support only from majority Democrats in both chambers.

On Friday, Polis signed a third bill that affects metropolitan planning organizations into law: House Bill 1304.

The measure prohibits municipalities from enforcing minimum parking requirements for people with disabilities, parking for bicycles, multifamily developments, or other limited exemptions. It was amended to limit its impact to within a quarter mile of bus or other transit stations.

Opponents said the bill would affect established neighborhoods.