City of Boulder staff are proposing an ordinance that would prohibit any municipal water customer from installing graywater reuse systems. Graywater is lightly used water — such as from showers and laundry — that can be treated and reused for household purposes like flushing toilets and underground irrigation with specialized plumbing.
The proposal comes as a response to House Bill 24-1362, which would automatically allow new construction to include graywater systems by the start of 2026 as Colorado faces long-term drought and supply pressures, unless cities opt out.
Boulder currently does not permit any graywater reuse systems. To comply with HB 24-1362, the city would have to establish a local graywater control program to regulate all related activities. That would include creating a new code, overseeing design and inspections, and handling enforcement to meet state and federal standards.
Analysis by city staff from a pilot program in a CU Williams Village dorm found that graywater conserved only 1% of communal water use. The project was expensive to maintain while conserving less water than expected, according to the city. In comparison, replacing indoor fixtures — specifically toilets and washing machines — reduced per-person water use by almost one-third. A graywater reuse program could also pull resources away from other water conservation efforts, staff argued. Interest has also been generally low. In Colorado, seven communities allow graywater but only two have seen uptake, despite full rebates.
The ordinance was brought before the Water Resources Advisory Board on Sept. 15 to discuss compliance with state law. After deliberation, the board clarified that the ordinance would not prohibit casual graywater reuse (such as capturing water while waiting for a shower to warm and using it to water plants) or affect existing uses. The board voted to recommend the ordinance.
City council review is scheduled for Oct. 16 and Nov. 6, with public comment opportunities. If approved, the ordinance would take effect before Jan. 1.
City staff said they remain open to considering graywater systems as part of water conservation strategies in the future as technologies improve.
sorry, but it defies logic that graywater use conserves only 1% of water. i have to wonder what the backstory is, especially when the city wants to limit daytime watering–which i totally support.