Contra Costa County Municipal Code Art. 420-6.8 Sewage Disposal Systems

An onsite wastewater treatment system may be constructed only on a site that conforms to applicable setbacks and groundwater depth, ground slope, soil depth and percolation rate standards specified in the sewage regulations.

(Ord. No. 2018-25 § III, 9-11-18)

(a) Sewage flow. An onsite wastewater treatment system must be sized to accommodate the maximum volume of sewage that the system is projected to receive in a twenty-four-hour period.

(b) Components. The septic tank, transport lines, pump tank, disposal field and any supplemental treatment unit in an onsite wastewater treatment system constructed under Subsection 420-6.404(a)(1), and the reserve area for the system, must conform to all applicable design standards set forth in the sewage regulations.

(Ord. No. 2018-25 § III, 9-11-18)

(a) The construction, alteration, relocation or replacement of an onsite wastewater treatment system, or any primary components thereof, may be lawfully performed only under a valid construction permit issued by the health officer. "Alteration," as used in this section, means a change that causes an onsite wastewater treatment system, or primary component thereof, to function in a manner that is inconsistent with the design approved by the health officer, including but not limited to a change in design daily sewage flow and the installation of supplemental treatment units.

(b) The construction, alteration, relocation or replacement of an onsite wastewater treatment system, or any primary components thereof, may be lawfully performed only if the health officer has determined that a sanitary sewer is not available for connection to the structure to be served by the system.

(c) All work on an onsite wastewater treatment system under a construction permit issued under Section 420-6.808 must be inspected and approved by the health officer prior to use of the onsite wastewater treatment system.

(Ord. No. 2018-25 § III, 9-11-18)

(a) Application; issuance. An application for a construction permit required under Section 420-6.806 or 420-6.1004 must be submitted to the health officer. The health officer will accept an application for a construction permit only if the application is complete and accompanied by payment of a permit fee established by the board by resolution. The health officer will approve a permit application and issue a permit based solely on compliance with this chapter and the sewage regulations.

(b) Expiration. Every construction permit issued by the health officer under this chapter becomes void if the work authorized by the construction permit is not commenced within one hundred eighty days from the permit's date, or if the work is suspended or abandoned for one hundred eighty days without excuse satisfying the health officer as being beyond control of and remedy by the permittee. Work under a construction permit will be deemed to have commenced if at least one health officer inspection of construction has been completed within one hundred eighty days of the permit issuance date. Once a construction permit becomes void, a new construction permit must be obtained before any work is commenced or recommenced, and a new permit fee must be paid.

(c) Renewal. Any permittee holding an unexpired construction permit may apply to the health officer for a permit extension upon a showing of good and satisfactory reason acceptable to the health officer. If the permittee is unable to commence work within the time required by this section, the health officer may extend the time of the permit for a period not exceeding 180 days upon written request by the permittee. No permit may be renewed more than once.

(d) Permit not approval of violations. The issuance of a construction permit under this chapter will not be construed as a permit for an approval of any violation of this chapter or code or determination that the permittee is the owner of the subject property or otherwise authorized to do the work for which the permit has been issued. No construction permit presuming to give authority to violate or cancel the provisions of this chapter will be valid except insofar as the work that it authorizes is lawful. The issuance of a construction permit based on plans and specifications does not prevent the health officer from later requiring the correction of errors in the plans and specifications or from preventing work under the permit in violation of this chapter.

(Ord. No. 2018-25 § III, 9-11-18)

(a) Mandatory use. Septic tank effluent must undergo supplemental treatment in an onsite wastewater treatment system if:

(1) The system utilizes a drip dispersal system;

(2) The system is located in an area where the depth from the natural grade to the anticipated highest seasonal level of groundwater is less than 3 feet;

(3) The system will receive high strength wastewater; or

(4) The system will replace another onsite wastewater treatment system and cannot meet the required horizontal setback from a public water well or a public water system's surface water intake point, unless the health officer makes both of the following two findings:

(A) There is no indication that the system to be replaced is adversely affecting the public water source; and

(B) There is limited potential that the replacement system could impact the public water source.

(b) Monitoring.

(1) The owner of an alternative onsite wastewater treatment system shall monitor the operation of the system for as long as the system remains in use, in accordance with the sewage regulations.

(2) A person may not use or operate an alternative onsite wastewater treatment system if the owner of that system fails to monitor that system in accordance with the sewage regulations.

(c) Mitigation measures.

(1) The owner of a replacement alternative onsite wastewater treatment system that does not conform to applicable horizontal setbacks from a public water well or a public water system's surface water intake point must comply with applicable mitigation measures set forth in the sewage regulations unless the health officer makes the findings set forth in Subsections (a)(4)(A) and (a)(4)(B) of this section.

(2) A person may not use or operate a replacement onsite wastewater treatment system described in Subsection (c)(1) of this section if the owner fails to comply with any applicable mitigation measure.

(Ord. No. 2018-25 § III, 9-11-18)