Agenda Memo

City of Boulder City Council Agenda Item Meeting Date: December 4, 2025 Agenda Title Third reading and consideration of a motion to adopt Ordinance 8720 amending Chapter 10-10, B.R.C. 1981, by adding a new Section 10-10-3, “Prohibition on the Installation and Use of Graywater Treatment Works” prohibiting graywater use by persons served through the city’s water utility; and setting forth related details

Staff Contact Kim Hutton, Water Resources Manager, Utilities Joe Taddeucci, Director of Utilities

Draft Motion Language Staff requests council consideration of this matter and action in the form of the following motion: Motion to adopt Ordinance 8720 amending Chapter 10-10, B.R.C. 1981, by adding a new Section 10-10-3, “Prohibition on the Installation and Use of Graywater Treatment Works,” B.R.C. 1981, prohibiting graywater use by persons served through the city’s water utility; and setting forth related details.

Executive Summary The purpose of this item is for City Council to consider Ordinance 8720 (Attachment A) that would authorize temporary changes to the Boulder Revised Code to comply with House Bill 24-1362 (Attachment B). House Bill 24-1362 mandates that graywater reuse in new construction be automatically allowed, including the requirement for the city to develop proper codes and establish and operate a local graywater control program

beginning January 1, 2026, unless the city expressly opts out. Passing Ordinance 8720 before the January 1, 2026, state deadline does not change current practice, since graywater systems currently do not have a regulatory framework and permitting process in the city. Passing ordinance 8720, which will sunset on December 31, 2027, also does not prevent the city from allowing graywater reuse in the future. The Boulder community is deeply committed to water conservation, and the city has been expanding its Water Conservation Program in alignment with the 2023 Water Efficiency Plan (Attachment C). While not identified as a priority action in the efficiency plan, staff recognizes that graywater holds appeal as a visible and tangible way to conserve water, which aligns strongly with Boulder’s environmental values. However, a comprehensive review shows that graywater systems would conserve less than 1% of Boulder’s total water use, which is a low water conservation return compared to a resource-intensive program to initiate, administer and regulate. Staff estimate that establishing a local graywater control program would take at least two years, making it infeasible before the state’s January 1, 2026 deadline. Accordingly, passage of Ordinance 8720 is necessary to ensure the city remains in compliance with the law, even if the city decides to allow graywater use at a future time.

Council Action Options Option

Outcome

Approve motion language as drafted

If the motion is approved, Ordinance 8720 would go into effect by January 3, 2026, two days following the House Bill 24-1362 deadline. Staff will communicate delays to state officials.

Define and adopt a modified motion

Not recommended. Council approved an amendment on second reading to include a December 31, 2027, sunset provision, which has been incorporated for third reading. Any further modifications will require another reading on emergency in order to comply with the state’s January 1, 2026, deadline.

Deny the motion or take no action

If the recommended motion fails or no action is taken, the ordinance would not move forward to adoption. House Bill 24-1362 will take effect on January 1, 2026, and the City would be out of compliance with state law and drinking water regulations. If the city does not opt out through adoption of this ordinance, graywater systems will automatically be allowed. However, to comply with state regulations for graywater systems,

the city would have to adopt building codes and a permitting program that prevent graywater from entering the city’s potable water system. Staff estimate it would take at least 2 years to develop such a program. Refer back to staff

Not recommended. If Council refers this item back to staff, there would not be sufficient time before January 1, 2026, to develop a graywater program.

Alignment with City Plans and City Council History Sustainability, Equity, and Resilience (SER) Framework and Citywide Strategic Plan Alignment SER Framework Goal Area Responsibly Governed: Ordinance 8720 reduces the city’s liability and ensures compliance with state law. Safe: Graywater contains pathogens that pose health and safety concerns. Citywide Strategic Plan N/A Staff Notes N/A

Alignment with Additional City Plans Boulder’s 2023 Water Efficiency Plan, and related community engagement associated with development of the plan, considered graywater but prioritized other strategies that offer greater water savings and better align with available resources.

City Council History This item is not tied to a council priority. Changes to Boulder’s municipal code are necessary by January 1, 2026, to comply with recent state legislation (House Bill 241362). City Council considered Ordinance 8720 on first reading on October 16, 2025 and had no questions. On November 6, 2025, City Council considered Ordinance 8720 on second reading and requested the addition of a December 31, 2027 sunset provision, which has been added to Ordinance 8720. Staff understands that Council intends for the sunset provision to trigger a review of the graywater opt-out decision in two years, with no expectation that staff will have a graywater program ready to implement at that time unless Council provides further direction prior to the sunset.

In 2013 and 2020, city council approved memorandums of understanding with the University of Colorado for a graywater pilot project under a research exemption. The University installed a graywater system in one of the Williams Village residence halls to evaluate treatment technology and water efficiency affiliated with graywater systems as well as economic, environmental, and institutional factors that influence decisions to install residential graywater systems. The University decommissioned the Williams Village graywater system in 2023 after about ten years of periodic use. The system was decommissioned because it did not receive ongoing research interest, conserved less water than expected, was expensive to maintain, lacked reliable manufacturer support, and required specialized expertise to operate. Even though the pilot was discontinued, the project provided valuable insights into practical considerations for graywater reuse.

Analysis Graywater reuse involves diverting gently used wastewater from drains of sinks, showers, bathtubs, and laundry machines for secondary use on the same property, typically toilet flushing or subsurface irrigation. This practice can reduce the volume of potable water drawn from the tap by reusing graywater for indoor or outdoor applications. Graywater reuse does not include daily water saving techniques such as collecting shower warm-up water in a bucket to use on plants, and such techniques would not be prohibited by the proposed ordinance. In 2013, Colorado enacted HB13-1044, which allowed local governments to permit graywater reuse if they opted in and established a local graywater control program meeting federal and state standards. The state revised graywater legislation in May 2024 with HB24-1362, which shifts the policy to automatically allow graywater reuse in new construction starting in January 2026 unless a jurisdiction specifically opts out. A jurisdiction that allows graywater systems to be installed must also establish a local graywater control program. Staff estimate that establishing a local graywater control program would take a minimum of two years and is not feasible prior to the January 1, 2026, deadline; therefore, the city would need to initially opt-out of allowing graywater to comply with HB24-1362 and state and federal regulations. Passing Ordinance 8720 to meet the January 1, 2026, deadline does not prevent the city from allowing graywater reuse in the future. Aside from the January 1, 2026, deadline, staff have extensively evaluated the benefits and challenges of allowing graywater as detailed below. Water Conservation Potential: The water conservation potential of a local graywater control program depends heavily on community participation and which fixtures are connected to individual systems. In comparison to high-impact measures, such as installing efficient indoor fixtures and converting turf to water-wise landscaping, graywater would conserve modest amounts of water, estimated at less than 1% of total community

water use. By contrast, most of the city’s 30% per-person reduction in water use since the early 2000s has come from replacing indoor fixtures, particularly toilets and clothes washers. Additionally, staff are currently expanding Boulder’s Water Conservation Program in alignment with the 2023 Water Efficiency Plan that was guided by community feedback, included use of the city’s racial equity instrument, and prioritized strategies with high return on investment and community benefit, such as an income-qualified fixture replacement program. Establishing a local graywater control program would either require allocation of additional staff resources or would divert staff from working on other higher priority water conservation programs identified in the 2023 Water Efficiency Plan. Administrative Complexity: The state does not directly regulate individual graywater systems, so local governments must establish their own local graywater control programs if they choose to allow them. For Boulder, this would involve adopting new regulations, creating permitting processes, reviewing system designs, conducting inspections, tracking backflow prevention program surveys and annual inspections, maintaining a database of approved systems, and enforcing against violations. Staff estimate establishing a local graywater control program would take at least two years and require up to two full-time equivalents. The exact timeline and staffing needs would depend on whether the program allowed only a few types of graywater systems or a broad range. Public Health and Safety Concerns: Graywater can contain pathogens, heavy metals, and other contaminants and therefore must be carefully regulated to protect public health and prevent contamination of the treated drinking water system. To comply with state drinking water regulations and protect the city’s drinking water system, properties with graywater systems would require an additional permit and inspection and would also need to be incorporated into the city’s backflow prevention survey and tracking program requiring additional resources and staffing. Water Rights Considerations: From a water rights perspective, water reuse and water conservation differ. Water reuse involves collecting water and using it a second time, which can reduce the amount of water returning to the river for other downstream users. Water conservation simply means using less water overall. Some of the city’s water supplies carry specific restrictions on reuse. Allowing graywater reuse

would complicate management of these supplies and require additional oversight to ensure that only water legally available for graywater reuse is directed into graywater systems. Limited Regional Adoption: Since 2013, only a small number of Colorado communities have adopted local graywater control programs, and of the communities that have programs, very few systems have been installed. Additionally, communities in Colorado, Arizona, and Texas who have encouraged graywater reuse through a variety of methods, ranging from rebates to required plumbing stub outs in new construction, have seen limited uptake. To ensure compliance with HB24-1362, multiple communities have opted out of allowing graywater including Arvada, Aurora, Boulder County, Lafayette, and Thornton. Based on this analysis, the cumulative burdens and public health risks of establishing and maintaining a local graywater program outweigh the anticipated water conservation benefits at this time. The city’s focus on widely adopted water conservation measures, such as water-wise enhancements to the city’s landscaping code and establishing an income qualified fixture replacement program, offers a more reliable and manageable path forward. Staff therefore recommend that the City of Boulder adopt Ordinance 8720 to opt out of graywater reuse under HB24-1362 through December 31, 2027, while continuing to monitor advancements in graywater. Opting out now does not preclude the city from revisiting graywater reuse in the future.

Equity Analysis The Racial Equity Instrument was used to guide priorities in the 2023 Water Efficiency Plan and informs priorities of Boulder’s water conservation program. For example, developing an income-qualified water efficient water fixture replacement program and building water conservation partnerships with existing community groups was prioritized in the 2023 Water Efficiency Plan. Ordinance 8720 will allow the continued prioritization of planned water conservation strategies for the next two years.

Fiscal Note A Fiscal Note for Ordinance 8720 is not needed since no changes are proposed for current appropriations.

Climate, Resilience, and Sustainability Considerations Given the goal of conserving water throughout the city, actions identified in the 2023 Water Efficiency Plan continue to be the most effective use of available resources. The Boulder community is deeply committed to water conservation, and staff recognize that

graywater holds appeal as a visible and tangible way to reduce water use. Staff continue to promote actionable steps community members can take to use water responsibly that encompass a wide range of opportunities from behavior changes to technology upgrades to re-imagining how water is used on our landscapes.

Community Engagement Community engagement during development of the city’s 2023 Water Efficiency Plan included activities such as online questionnaires, stakeholder meetings, and staff workshops to select and prioritize water conservation efforts. The community was informed of graywater code changes through development of a graywater webpage and circulation of the August 2025 Planning & Development Services newsletter. Additionally, an information item was provided to Planning Board on September 16, 2025, and a public hearing was held at the Water Resources Advisory Board (WRAB) meeting on September 15, 2025. WRAB made a motion 3 (yes) to 0 (no) to recommend adoption of Ordinance 8720 to council. WRAB members requested additional information related to staffing needs and return on investment, which has been incorporated into this memo. Additionally, WRAB was supportive of staff continuing to monitor graywater and returning to WRAB at a later date if conditions for a graywater program become more favorable. Following WRAB’s recommendation and in response to public comment, a definition of “graywater treatment works” was added to Ordinance 8720. City Council considered Ordinance 8720 on first reading on October 16, 2025 and had no questions. On November 6, 2025, City Council considered Ordinance 8720 on second reading and requested the addition of a December 31, 2027 sunset provision, which has been added to Ordinance 8720.

Workplan Considerations The December 31, 2027 sunset provision in Ordinance 8720 will require staff to revisit the graywater opt-out consideration in 2027. Staff will not begin work on developing a local graywater control program before the ordinance sunsets unless future discussions with Council indicate otherwise. Staff estimate that establishing a local graywater control program would take a minimum of two years.

Next Steps for City Council Council has the option to adopt the proposed ordinance or not. No additional action is necessary if City Council approves of the ordinance, and staff will begin updating the municipal code to support compliance by January 1, 2026.

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Attachments A – Proposed Ordinance 8720 B – House Bill 24-1362 C – City of Boulder 2023 Water Efficiency Plan