Vol. 39 Iss. 4 - October 10, 2022

Chapter 860



Final Regulation

REGISTRAR'S NOTICE: The State Water Control Board is claiming an exemption from Article 2 of the Administrative Process Act in accordance with § 2.2-4006 A 4 a of the Code of Virginia, which excludes regulations that are necessary to conform to changes in Virginia statutory law or the appropriation act where no agency discretion is involved. The board will receive, consider, and respond to petitions by any interested person at any time with respect to reconsideration or revision.

Title of Regulation: 9VAC25-860. Virginia Pollutant Discharge Elimination System General Permit for Potable Water Treatment Plants (amending 9VAC25-860-10; repealing 9VAC25-860-30).

Statutory Authority: § 62.1-44.15 of the Code of Virginia; § 402 of the Clean Water Act; 40 CFR Parts 122, 123, and 124.

Effective Date: November 9, 2022.

Agency Contact: Elleanore Daub, Department of Environmental Quality, 1111 East Main Street, Suite 1400, P.O. Box 1105, Richmond, VA 23218, telephone (804) 659-2655, FAX (804) 698-4178, or email


Pursuant to Chapter 356 of the 2022 Acts of Assembly, the amendments conform the regulation to a statutorily change shifting authority to issue and enforce permits from the State Water Control Board to the Department of Environmental Quality.

9VAC25-860-10. Definitions.

The words and terms used in this regulation shall have the meanings defined in the State Water Control Law and 9VAC25-31, the VPDES Permit Regulation, unless the context clearly indicates otherwise, except that for the purposes of this chapter:

"Board" means the State Water Control Board. When used outside the context of the promulgation of regulations, including regulations to establish general permits, "board" means the Department of Environmental Quality.

"Department" or "DEQ" means the Virginia Department of Environmental Quality.

"Membrane treatment" means a pressure driven process using synthetic materials to separate constituents from water. Membranes are used for dissolved solids or suspended solids removal. Membrane treatment for dissolved solids removal includes reverse osmosis and nanofiltration. Membrane treatment for suspended solids removal includes ultrafiltration and microfiltration.

"Microfiltration" means a method of membrane treatment designed to remove particles down to 0.1 µm in size. The treatment removes cysts, bacteria, and most (but not all) particulates.

"Nanofiltration" or "low-pressure reverse osmosis" or "membrane softening" means a method of membrane treatment designed to remove multivalent ions (softening) and removes contaminants down to 1 nm (nanometer = 0.001 µm) in size.

"Potable water treatment plant" means an establishment engaged in producing water for domestic, commercial, or industrial use as designated by North American Industry Classification System (NAICS) Code 221310 - Water Supply and Irrigation Systems, (Executive Office of the President, Office of Management and Budget, United States, 2017), Standard Industrial Classified (SIC) Code 4941 - Water Supply (Office of Management and Budget (OMB) SIC Manual, 1987), or others as approved by the board.

"Reverse osmosis" means a method of membrane treatment designed to remove salts and low-molecular weight solutes and remove all contaminants down to 0.0001 µm (microns) in size. Reverse osmosis methods apply pressure in excess of osmotic pressure to force water through a semi-permeable membrane from a region of high salt concentration to a region of lower salt concentration.

"Total maximum daily load" or "TMDL" means a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards and an allocation of that amount to the pollutant's sources. A TMDL includes wasteload allocations (WLAs) for point source discharges, and load allocations (LAs) for nonpoint sources or natural background or both, and must include a margin of safety (MOS) and account for seasonal variations.

"Ultrafiltration" means a method of membrane treatment designed to remove particles down to 0.01 µm in size. The treatment removes cysts, bacteria, and viruses as well as suspended solids.

9VAC25-860-30. Delegation of authority. (Repealed.)

The director, or an authorized representative, may perform any act of the board provided under this chapter, except as limited by § 62.1-44.14 of the Code of Virginia.

VA.R. Doc. No. R23-7278; Filed September 09, 2022