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Onsite Wastewater Treatment Systems (Septic) Ordinance - Effective 12/26/13

Last modified: 3/4/2015 5:47 PM

Update (12/6/13): The OWTS ordinance was passed by the Santa Clara County Board of Supervisors and becomes effective December 26, 2013.  All land use projects submitted on or after this date will be reviewed using the new ordinance.

Update (11/19/13): An updated OWTS FAQ has been posted below.

Update (9/16/13): An updated OWTS Technical Manual has been posted below.

The County of Santa Clara adopted a new ordinance that updates and replaces the existing County regulations governing individual on-site wastewater treatment systems (OWTS) within the unincorporated part of the County. The modifications eliminate inconsistencies with Regional Water Quality Boards’ regulation and directions. Besides allowing a broader range of treatment and dispersal designs (alternative systems that use pre-treatment technologies), the ordinance eliminates the 1-acre minimum lot size requirement for installation of OWTS in the Lexington Basin. The project also includes changes to a County General Plan policy and supporting descriptive text that reference use of alternative OWTS as well as a change to the Zoning Ordinance eliminating the minimum lot size requirement for secondary dwelling units in the San Martin Planning Area. These changes reflect the current state of science regarding OWTS and will ensure consistency between the proposed Ordinance and the General Plan.


Final Program Environmental Impact Report (FPEIR)

Onsite Wastewater Treatment System (OWTS) Ordinance
OWTS Ordinance
OWTS Technical Manual

Frequently Asked Questions on OWTS
Onsite Wastewater Treatment Systems FAQ - 11/19/13