In this chapter:
(1) "Commission" means the Texas Commission on Environmental Quality.
(2) "On-site wastewater treatment system" means a system of treatment devices or disposal facilities that:
(A) is used for the disposal of domestic sewage, excluding liquid waste resulting from the processes used in industrial and commercial establishments;
(B) is located on the site where the sewage is produced; and
(C) produces not more than 5,000 gallons of waste a day.