It is expressly found and determined that more restrictive amendments to the 2022 California Plumbing Code adopted in § 63.0301 and its appendices adopted in § 63.0304 are reasonably necessary because of local climatic, geological, and topographical conditions existing in the County which are more specifically described as follows:
(a) The buildup of nitrate in groundwater poses a threat to public health and is one of the potentially significant long-term consequences of on-site sewage disposal practices; on-site private sewage disposal systems contribute to the discharge of nitrates and other pollutants into the groundwater table within the planning areas for the spheres of influence of the Cities of Chino and Montclair; the failure of private sewage disposal systems is a threat to the health of the public; and the orderly development of these areas is promoted by requiring development to connect to public sewers in order to obtain the maximum benefit from existing infrastructure.
(b) The mountain areas of the County are generally unsuitable for the installation of private sewage disposal system seepage pits due to thin soils over bedrock, steep slopes and/or locally high groundwater.
(c) Geologic conditions within the County make increasing the minimum separation between a well and a septic tank from 50 feet to 100 feet reasonably necessary for the protection of water quality in water supply wells. Soils are generally sufficiently porous so that should a septic tank have structural failure due to corrosion, earthquake damage, or by other means, 50 feet does not provide sufficient separation to prevent contamination of nearby wells from the leaking contents.
(d) Geologic conditions within the County make increasing the minimum separation between a well and a soil absorption portion of a sewage disposal system discharging 5,000 gallons per day or more from 100 feet to 200 feet reasonably necessary for the protection of water quality in water supply wells. Local soils are generally porous so that where large volumes of sewage effluent are discharged closer than 200 feet, the cone of depression created by pumping a well may intercept significant amounts of sewage effluent, thereby contaminating the water produced by the well.
(e) Geologic conditions within the County in the vicinities of the Colorado and Mojave Rivers make increasing the minimum separation from the soil absorption portion of a sewage disposal system from 100 feet to 200 feet reasonably necessary to protect the beneficial uses of these rivers as drinking water supplies. Both rivers flow through highly porous material and both rivers either directly or by nearby wells provide the primary sources of drinking water to residents and communities along their courses.
(Ord. 4452, passed - -2022)