Arapahoe County leans toward opting out of greywater systems after HB 24‑1362; staff to draft resolution

Arapahoe County commissioners spent the bulk of a study session reviewing options for regulating greywater (also referred to as graywater or greenwater) following passage of House Bill 24‑1362. Staff briefers outlined technical considerations, peer‑jurisdiction experience and fiscal impacts and sought direction from the board on whether to allow, prohibit, or partially restrict greywater systems ahead of the state deadline.

"House Bill 24 13 62" was cited by staff as changing the statewide default: unless a county opts out, certain graywater systems would be automatically allowed beginning Jan. 1, 2026. Steve (staff) told the board the county must decide whether to opt out of specified systems or prepare to administer permitting, inspections and reporting requirements under CDPHE regulation 86.

Diana, the public‑health presenter, gave a primer on what counts as greywater and how it is typically used. "It includes several places within your home, including your bathroom sink, your bathtub, your shower, your laundry sink, and your laundry machine," she said, and she emphasized that greywater does not include toilet water, kitchen sink or dishwasher effluent. Diana highlighted public‑health and operational concerns, including studies finding comparable bacteria and nutrient concentrations in some sink or laundry effluents, cross‑connection risks, and substantial maintenance burdens for homeowners.

Staff summarized three policy options: take no action (allow and prepare to regulate, with an estimated 0.75–1.25 FTE across departments and software changes), adopt a resolution to prohibit all greywater systems within unincorporated Arapahoe County (opt out), or adopt the Board of Health’s preferred hybrid approach that would prohibit outdoor laundry‑to‑landscape reuse while continuing to allow indoor reuse for toilet/urinal flushing under existing plumbing code provisions.

Public Works and code staff said indoor flushing systems are covered under the county’s adopted International Building Code but that laundry‑to‑landscape lacks standard code language and would require development of new local code and design criteria. Brian Wymer (Public Works) noted technical and maintenance constraints for laundry‑to‑landscape systems, including the need for diverter valves, annual tank draining requirements under code, and freeze‑thaw concerns in Colorado.

Commissioners raised retrofit cost and cost‑benefit questions. Staff cited examples: a Colorado State University residence‑hall internal flushing system reportedly cost roughly $66,000 to install for 14 rooms, with estimated operation and maintenance of $5,000 per year and a very long return on investment; other cited residential estimates ranged from about $8,000 to $15,000 depending on home size. Survey outreach to about 90 entities returned 17 responses (~20%): 7 opposed any reuse, 4 favored laundry‑to‑landscape, 2 favored indoor flushing, 3 favored both and 1 left the question blank.

After discussion, the chair asked for a thumbs poll on policy options. The board recorded four thumbs in favor of policy option 2 (prohibit all greywater systems in unincorporated Arapahoe County) and one thumb for option 3 (prohibit outdoor systems, allow indoor). Staff said they would draft resolution language to implement the board’s direction and include provisions to revisit the policy if demand, technology or regulatory circumstances change. No formal ordinance or code amendment was adopted at the session.

Next steps noted by staff included drafting a resolution if the board desires, designating a lead agency for any future administration, and minimal tracking/administrative work if applications appear. Commissioners emphasized the option to revisit the policy in the future should technology improve or demand increase.