Boulder, CO Water Use Rules: Recycled Water Rules (2026)

Section 10-10-3(a) states plainly that no person served with water through the city's water utility shall install graywater treatment works or use graywater. The section defines "graywater" as wastewater collected from fixtures within residential, commercial, or industrial buildings or institutional facilities, before it is treated or combined with other wastewater, for the purpose of being put to a beneficial use, and defines "graywater treatment works" as an arrangement of devices and structures used to collect graywater from within a building or facility and to treat, neutralize, or stabilize it to the level necessary for its authorized uses.

The prohibition sits alongside a matching deletion elsewhere in the same chapter: the adopted International Plumbing Code's Chapter 13, "Nonpotable Water Systems," and Chapter 14, "Subsurface Graywater Soil Absorption Systems," are both struck from the plumbing code in their entirety, so there is no path to a graywater permit through the plumbing code either. The ban is not permanent as written: Section 10-10-3(e) states that the section, and the additions made by Ordinance No. 8720, expire on December 31, 2027 unless the city council acts to extend them before that date, meaning the current graywater prohibition is a time-limited policy rather than a fixed part of the code.