(a) An authorization from the commission is not required for the use of graywater and alternative onsite water from a graywater reuse system or a combined reuse system for agricultural purposes. Treatment required by this section does not require authorization from the commission.
(b) The graywater and alternative onsite water must be generated and used onsite.
(c) Graywater reuse systems and combined reuse systems are not authorized to overflow onto the ground under any circumstances.
  (1) Graywater reuse systems must be designed and constructed so that 100% of the graywater can be diverted to an organized wastewater collection system or on-site sewage facility (OSSF), unless prohibited by Chapter 285, Subchapter H of this title (relating to Disposal of Graywater). The graywater must be diverted during periods of non-use of the graywater reuse system or if the system reaches maximum capacity. The graywater must enter the organized wastewater collection system or OSSF through either one air gap or two backflow valves or backflow preventers.
  (2) Combined reuse systems must be designed and constructed so that 100% of the graywater can be diverted to an organized wastewater collection system or OSSF, unless prohibited by Chapter 285, Subchapter H of this title prior to entering the combined reuse system. Graywater must be diverted to the organized wastewater collection system or OSSF during periods of non-use of the system or if the combined reuse system reaches 80% capacity. The graywater must enter the organized wastewater collection system or the OSSF through either one air gap or two backflow valves or backflow preventers.
  (3) Combined reuse systems that store stormwater, rainwater, and/or foundation drain water must have an automatic shutoff system to stop the inflow of stormwater, rainwater, and foundation drain water into the combined reuse system. The automatic shutoff system must activate when the combined reuse system reaches 80% capacity.
(d) Water from a graywater reuse system or a combined reuse system may be used for the following activities.
  (1) Process water. Water from a graywater reuse system or a combined reuse system that is used for irrigation and other agricultural purposes may be treated to a standard that allows the water to be used in operational processes.
  (2) Landscape maintenance. Water from a graywater reuse system or a combined reuse system that is used for landscape maintenance must meet the following limits.
    (A) If the water will be applied in areas with public access, the water must meet the following limits:
      (i) Escherichia coli (E. coli), 20 most probable number (MPN) or colony-forming units (CFU) per 100 milliliters (ml), 30-day geometric mean; or
      (ii) E. coli (not to exceed), 75 MPN or CFU per 100 ml, single grab sample.
    (B) If the water will be applied in areas with restricted access to the public, the water must meet the following limits:
      (i) E. coli, 200 MPN or CFU per 100 ml, 30-day geometric mean; or
      (ii) E. coli, 800 MPN or CFU per 100 ml, single grab sample.
  (3) Dust control. Water from a graywater reuse system or a combined reuse system that is used for dust control must meet the E. coli limits in paragraph (2)(B) of this subsection.
  (4) Irrigation of fields. Water from a graywater reuse system or a combined reuse system that is used to irrigate fields where edible crops are grown or fields that are pastures for milking animals, the water must meet the E. coli limits in paragraph (2)(A) of this subsection. E. coli limits do not apply to graywater and alternative onsite water that is used to irrigate fields other than those where edible crops are grown or fields that are pastures for milking animals.
  (5) Toilet or urinal flushing. Water from a graywater reuse system or a combined reuse system that is used for toilet or urinal flushing must meet the following requirements.
    (A) E. coli must be less than 2.2 MPN or CFU per 100 ml for 30-day geometric mean and less than 200 MPN or CFU per 100 ml maximum single grab sample.
    (B) Total suspended solids must be less than 10.0 milligrams per liter for 30-day geometric mean and less than 30.0 milligrams per liter maximum single grab sample.
    (C) All exposed piping and piping carrying graywater and/or alternative onsite water within a building must be either purple pipe or painted purple; all buried piping must be either manufactured in purple, painted purple, taped with purple metallic tape, or bagged in purple; and all exposed piping must be stenciled in yellow with a warning reading "NON-POTABLE WATER."
  (6) Other uses. Water from a graywater reuse system or a combined reuse system that is used for other similar activities must:
    (A) meet the E. coli limits in paragraph (2)(A) of this subsection if used in a way that the public may come into contact with the water; or
    (B) meet the E. coli limits in paragraph (2)(B) of this subsection if used in a way that the public will not come into contact with the water.
(e) Water from a graywater reuse system or a combined reuse system that is required to meet the E. coli limits in subsection (d) of this section must be monitored for E. coli at least monthly. These records must be maintained at the site and be readily available for inspection by the commission for a minimum period of five years.

Source Note: The provisions of this §210.85 adopted to be effective January 6, 2005, 29 TexReg 12195; amended to be effective December 29, 2016, 41 TexReg 10364