(a)  Notwithstanding any other provision of this article, an in-ground sump, used by a pest control operator licensed under Section 11705 of the Food and Agricultural Code, or used by a local or state agency, which meets all of the specifications listed in subdivision (b) and complies with subdivision (c), is exempt from the requirements of subdivision (a) of Section 25208.4, Section 25208.5, and Section 25208.8 if, prior to installation, the plan for the in-ground system is submitted to the regional board and the regional board determines that the system complies with this section.

(b)  For purposes of this article, an “in-ground sump” shall have the following specifications:

(1)  It consists of two containment units. The primary container is constructed primarily of nonearthen materials, including, but not limited to, stainless steel or plastic, and is designed to prevent the migration of any constituents into the secondary container. The secondary container is constructed of impermeable materials and is designed to prevent the migration of any hazardous waste constituents into the ground surrounding the secondary container. The secondary container shall also be designed to prevent the intrusion of groundwater, rainwater, or any other surface runoff into the space beneath the primary container.

(2)  It is designed to allow visual inspection of the space underlying the primary container each operating day.

(3)  The dimensions of the in-ground sump do not exceed six feet in depth, nor 75 square feet of surface area for each hazardous waste containment system.

(4)  The in-ground sump is used for pest control operations.

(c)  In order to qualify for the exemption, an in-ground sump shall be pumped empty of free liquid at least twice each operating day and these free liquids shall not be returned to the sump. The sump shall be visually inspected at least once each operating day. A record of all visual inspections shall be maintained by the pest control operator or local or state agency and shall be audited by the regional board at least annually.

(d)  If at any time the regional board determines that the primary container of an in-ground sump is leaking, the regional board shall immediately order the discharge to cease and shall either order installation of a new primary container as provided in paragraph (1) of subdivision (b) or revoke the exemption authorized by this section. Nothing in this section shall be construed to limit the regional board’s authority to take any action necessary to determine whether an in-ground sump poses any threat to the waters of the state.

(Added by Stats. 1985, Ch. 1400, Sec. 1.)