Backflow.

§ 7934. Backflow. (a) For purposes of this section: (1) “Backflow” means the movement of water back in the direction from which it was flowing. (2) “Backflow preventer” means a device that prevents backflow. (3) “Backsiphonage” means backflow caused by negative pressure, which occurs when there is a drop in water pressure resulting in the water flowing back into the water service line. (4) “Low hazard building” means a building in which any backflow that does occur meets the following conditions: a. Occurs only by backsiphonage. b. Does not create a health risk or health hazard. c. Does not disrupt the service of piped water for human consumption or impair the potability of that water. d. Does not pose a risk to any fresh water supply. e. The pumping system involved does not connect to a treatment system used to convey wastewater, fertilizers, or chemicals, or that is used to provide fire protection. f. The water system involved does not draw from more than 1 aquifer without a backflow preventer on the discharge line of each well. (b) Subject to subsection (c) of this section, a county or municipality may not require backflow preventers to be installed or, if already installed, to be subject to inspections, in low hazard buildings of any of the following types: (1) Single-family residences. (2) Single-family residences with conditional uses that permit professional offices. (3) Professional offices. (4) Commercial buildings. (c) If a low hazard building has fresh water supplied by a public well, backflow preventers must be installed in compliance with 7 DE. Admin. Code, Regulation 7301, governing the construction and use of wells.85 Del. Laws, c. 407, § 1;