House committee advances bill limiting retention basins in Great Salt Lake drainage

The Public Utilities and Energy Committee advanced House Bill 489 on a unanimous voice vote after a presentation by the bill sponsor, Representative Peterson. Peterson said the bill would generally eliminate the option to use retention basins and instead require detention basins in most new development that drains to the Great Salt Lake.

"It eliminates the option in most instances to use retention basins instead of detention basins," Peterson said, explaining that detention basins are designed to drain in a timely way so captured stormwater is routed downstream rather than allowed to evaporate or infiltrate locally.

The bill targets the Great Salt Lake drainage basin and, according to the sponsor, focuses on a small portion of precipitation captured by urban stormwater systems. Peterson told the committee that "of the rain that falls from the sky, we divert 7%" into the types of systems at issue and said the change is intended to get more of that water to the lake.

Public commenters and technical stakeholders raised concerns. Soren Simonson, executive director of the Jordan River Commission and staff to the Jordan River Watershed Council, told the committee that detention and retention basins play an important role in protecting water quality and that removing the ability to hold stormwater could reduce the capacity to capture pollutants. "We have some reservation about the loss of the ability to capture stormwater," Simonson said, urging the committee to study the concept further and to integrate it with ongoing groundwater and basin planning.

Justin Lee, deputy director of the Utah League of Cities and Towns, said city engineers and stormwater technicians want clearer technical guidance than the bill's current direction to "release as soon as possible." "Engineers generally like to have a little more guidance than ‘as soon as possible,’" Lee said, noting concerns about downstream flood risk, cumulative impacts and compatibility with MS4 stormwater permits.

Representative Peterson said he originally proposed a six‑hour drainage requirement but was advised staff should leave the exact timeframe to local engineers. He told the committee he is willing to return to the six‑hour figure and "work with the league" on an appropriate drainage timeframe to ensure basins do not stagnate.

Taz Biesinger of the Utah Home Builders Association urged passage, saying previous studies estimated that water infiltrating to groundwater could take decades to reach the Great Salt Lake and that HB 489 is a useful step. Peterson said the bill is not intended to be retroactive and would apply to future construction.

The committee placed HB 489 on the committee’s consent track by passing a motion to advance the bill with a favorable recommendation. The chair ruled the motion passed unanimously.

Next steps: the bill will move to the next committee or floor assignment according to normal legislative procedures.