Industrial Wastewater Works. Industrial wastewater works are classified into the seven classes set out in Table 1 of Regulation .16 of this chapter. Unless the Department determines that a reasonable potential exists to adversely affect the quality of the receiving body of water or the environment, the following categories are not industrial wastewater works as defined in Environment Article, §12-101(h), Annotated Code of Maryland: Petroleum storage and distribution facilities; Seafood processors; Vehicle washing facilities; Vehicle maintenance facilities; Sand and gravel facilities; Stone quarries; Industries dechlorinating supply water as their only treatment; Industries discharging only stormwater runoff; and Industries performing tank or pipe hydrostatic testing. The Department may require classification of any individual works within the categories identified under §A(2)(a)—(i) of this regulation. Classification of the pretreatment plants will be required only for significant industrial users. Wastewater Treatment Plants. Wastewater treatment plants are classified into the eight classes set out in Table 2 of Regulation .16 of this chapter. Wastewater Collection Systems. Wastewater collection systems are classified into the following two classes: Class 1—Wastewater collection systems with gravity flow; Class 2—Wastewater collection systems with gravity and pumped or vacuum flow. A wastewater collection system is not classified as a separate entity if it is under the operation and supervision of certified wastewater treatment plant personnel. Water Treatment Plants. Water treatment plants are classified into the six classes set out in Table 3 of Regulation .16 of this chapter. Water Distribution Systems. Water distribution systems are classified as one class, Water Distribution (WD). A water distribution system is not classified as a separate entity if it is under the operation and supervision of certified water treatment plant personnel.