City Councilwoman Amanda Sandoval wants an entire neighborhood in her northwest Denver district be rezoned to allow homeowners to add extra housing units to lots.

The District 1 councilwoman said her proposal to rezone the Chaffee Park neighborhood to allow what are known as accessory dwelling units, or ADUs, was informed in part by supportive neighbors.

Soon after she won her seat in last May’s municipal elections, the Chaffee Park neighborhood association came to Sandoval with the proposal. That led to an information-gathering process that included an online survey, mailings to homeowners, door-to-door canvassing and community meetings.

By the time the online survey closed in December, 386 responses had been received. About 67 percent supported a neighborhood-wide ADU rezoning.

Sandoval also consulted experts, including Renee Martinez-Stone, who has headed a project to put ADUs in reach of homeowners in west Denver neighborhoods that already are zoned for them.

Martinez-Stone pointed out to Sandoval that relatively few residents of neighborhoods such as Villa Park and Barnum were building them, in part because of the expense — an ADU can cost around $250,000 — and the challenge of navigating building codes. Sandoval said that high cost could actually reassure people who, during the public meetings on the Chaffee Park proposal, had expressed fear that the rezoning would result in their neighborhoods being overwhelmed with new construction. The councilwoman also said it underlined for her the need to put ADUs within reach of low-income homeowners who said during those public meetings that they saw granny flats as a way to earn extra money.

Sandoval said her office is working on writing the rezoning legislation, which will eventually be reviewed by city staff. Next steps also include a public hearing before the planning board and a discussion by City Council’s Land Use, Transportation and Infrastructure Committee, which will also provide chances for the public to weigh in. More public comment will be heard once the proposal reaches the full City Council.

In other words, it could be months before City Council votes on the idea.

Blueprint Denver is a policy document adopted by City Council almost a year ago that broadly spells out how land should be used and transportation should be planned as the city grows. It recommended that the city take steps to ease zoning issues and other barriers to building ADUs, seen as a way to add affordable housing options and as a possible “wealth-building tool for low- and moderate-income homeowners.”

ADUs are legal in 25 percent of Denver. In the neighborhoods where they are not, homeowners can come before City Council to request a rezoning for their lot. A neighborhood-wide rezoning has not been attempted until now.

Sandoval said she hoped the Chaffee Park “holistic approach” and the process she used to inform and consult with the neighborhood could be a model for other parts of the city.