§ 4.84.140. OWTS; subsurface dispersal systems requirements.

a.

The conventional dispersal method approved for use in San Mateo County shall be a gravity trench dispersal system designed and constructed as prescribed in the Onsite Systems Manual, with the total length determined based on soil percolation rates and the number of bedrooms, or in the case of non-residential design, projected wastewater flow rate of the building(s) being served. Trench system designs utilizing shallower trenches, chambers or other filter material in place of gravel may be approved by Environmental Health as prescribed in the Onsite Systems Manual.

b.

In addition to the provisions of subsection a., any OWTS proposed for construction on slopes exceeding thirty-five percent (35%) shall require the use of pressure-dosing distribution dispersal methods, which are classified as an alternative OWTS and shall be designed and permitted in accordance with applicable provisions contained in article 5 of this chapter and the Onsite Systems Manual.

c.

Alternative OWTS shall only be permitted as detailed in article 5 of this chapter.

(Ord. No. 04754, § 1, 1-5-2016)