(a) For the purpose of this chapter, graywater is defined as wastewater from showers; bathtubs; handwashing lavatories; sinks that are used for disposal of household or domestic products; sinks that are not used for food preparation or disposal; and clothes-washing machines. Graywater does not include wastewater from the washing of material, including diapers, soiled with human excreta or wastewater that has come in contact with toilet waste.
(b) Construction of a graywater reuse system, including storage and disposal systems, must comply with this chapter; Chapter 210, Subchapter F of this title (relating to Use of Graywater and Alternative Onsite Water); and any more stringent requirements of the local permitting authority. For the purposes of this subchapter, a graywater reuse system begins at the graywater stub-out of a single family dwelling.
(c) A graywater reuse system must not create a nuisance or damage the quality of surface water or groundwater. If a graywater reuse system creates a nuisance, threatens human health, or damages the quality of surface water or groundwater, the permitting authority may take action under §285.71 of this title (relating to Authorized Agent Enforcement of OSSFs).
(d) A graywater reuse system shall comply with the requirements of this subchapter as they existed on the date installation was completed. The previous version of this subchapter is continued in effect for this purpose. Any alterations to an existing system must comply with this chapter; Chapter 210, Subchapter F of this title; and any more stringent requirements of the local permitting authority.
(e) No reduction in the size of the on-site sewage facility (OSSF) will be allowed when using a graywater reuse system unless the OSSF meets all of the conditions and requirements of §285.81 of this title (relating to Requirements and Conditions for Potentially Reducing the Size of an OSSF Disposal System for a Single Family Residence with a Graywater Reuse System or a Combined Reuse System).
(f) If the OSSF is not a reduced OSSF as described in §285.81 of this title, the graywater from either a graywater reuse system or a combined reuse system authorized under Chapter 210, Subchapter F of this title may, be connected to the OSSF to dispose of the graywater during periods when graywater is not being reused. If the reuse system is a combined reuse system as defined under Chapter 210, Subchapter F of this title, the flows from alternative onsite water sources must be diverted and shall not be allowed to enter the OSSF. Alternative water reuse systems as defined in Chapter 210, Subchapter F of this title, shall not be connected to the OSSF as OSSFs are not authorized nor designed to treat or dispose of flows from alternative onsite water sources. The piping connecting the graywater to the OSSF shall meet the applicable requirements of Subchapter D of this chapter (relating to Planning, Construction, and Installation Standards for OSSFs).

Source Note: The provisions of this §285.80 adopted to be effective February 5, 1997, 22 TexReg 1114; amended to be effective June 13, 2001, 26 TexReg 4115; amended to be effective January 6, 2005, 29 TexReg 12204; amended to be effective December 29, 2016, 41 TexReg 10378