A controversial urban development bill narrowly passed a final floor vote at the end of the legislative session this week.

Senate Bill 3202 would allow two accessory dwelling units, or ADUs, to be built on residential properties.

Proponents of the measure say it would help create more affordable housing on land already zoned for it. At least one ADU is already allowed on most residential properties.

But it’s become one of the most highly debated measures this session thus far.

During the final floor vote this week, 22 out of 51 state representatives and nine out of 25 senators voted against the bill. They worry about overcrowding and the development of monster homes, and say the measure won’t actually lead to more affordable housing.

Most of the discussion on the measure this week came from the House. Much of the opposition came from lawmakers who represent urban Honolulu.

The Honolulu City Council even passed a resolution opposing the measure.

“It’s trying to pack in more houses into our neighborhoods where that was never the intention, and that would change the fundamental nature of our communities — and that, I can’t support,” said Rep. Scot Matayoshi, who represents Kāne‘ohe and Maunawili.

He said the construction of vertical housing along the rail on Oʻahu should be the focus when it comes to improving the affordable housing supply.

Opponents of the bill say the infrastructure in many neighborhoods won’t be able to handle the additional residents.

“This is urban sprawl, and that is not the answer to our housing crisis. Most of our districts are already struggling with overburdened sewer systems and roadway congestion,” said Rep. Natalia Hussey-Burdick, who represents Kailua.

“If every lot could suddenly generate an additional two to three times the rental income by adding ADUs, it will actually increase the cost to buy the whole lot and push the dream of home ownership even further away from our younger generations,” she added.

Others worry that the measure would only benefit developers who can flip properties into monster homes and sell or rent them out for prices that are too expensive for residents.

SB3202 was largely nullified earlier in the session after lawmakers removed language about ADUs and the minimum lot sizes in which those units could be packed.

But in a sudden move during conference hearings — when changes to bills are often made without public input — the counties were given two options, both of which would require additional ADUs on more residential properties.

Under the current language of the bill, counties can choose to allow two ADUs on all properties or just in certain districts.

Rep. Luke Evslin, who chairs the House Committee on Housing, was involved in removing SB3202’s language about minimum lot sizes, which was the city council’s most problematic part of the bill.

But he was in support of the new and restored version of the measure. He said the counties still have flexibility and authority over housing development and can continue to “impose all of their existing development standards or impose new development standards.”

He supported the measure in response to the dire need for affordable housing in Hawaiʻi.

“I think that this is the greatest public policy challenge of our time. How do we fulfill … the twin tenants of our state land use law: to make it easy to develop housing in the urban state land use district and preserve and protect agricultural land?” Evslin asked.

“SB3202 is not going to solve the housing crisis, but it’s a step in the right direction,” he said.

Other lawmakers said that the high cost of living in Hawaiʻi is already a problem and that the state Legislature needs to be bolder in its attempt to keep residents at home.

Rep. Nicole Lowen, whose district includes Kailua-Kona, added that long-term infrastructure issues shouldn’t stifle progress on housing development.

“Sometimes moving forward is hard and yes, increasing density means you also have to look at traffic and infrastructure and other things, but we can’t continue to use the need for all those things at the same time to be an excuse (not) to take action on anything,” she said.

The state Department of Business, Economic Development and Tourism’s latest projections say that upwards of 41,000 additional housing units are needed in Hawaiʻi by 2035 to keep up with demand.