Santa Clara County Municipal Code Art. 3 Alternative Onsite Wastewater Treatment Systems

(a) Alternative OWTS may be permitted by the Director for the repair or upgrading of any existing OWTS and for new construction on any legally created parcel where:

(1) It is determined that sewage cannot be disposed of in a sanitary manner by a conventional septic tank-dispersal field system; or

(2) The Director determines that an alternative system would provide equal or greater protection to public health and the environment than a conventional septic tank-dispersal field system.

Such alternative OWTS must comply with the specific requirements set forth in this Section and as prescribed by the Director in the Onsite Systems Manual.

(b) Types of alternative OWTS permitted shall be limited to those identified in the Onsite Systems Manual for which siting and design standards have been adopted, and which have been approved by the Director and the appropriate California Regional Water Quality Control Board(s).

(c) All alternative systems shall be installed by a contractor duly licensed by the Contractors State Licensing Board of the State of California to install OWTS. Where the installation includes a proprietary treatment system, the contractor shall also possess any required manufacturer certifications, as applicable.

(d) Notwithstanding any other provisions of this Section, the Director shall have the authority to deny and/or require modifications to any alternative OWTS proposal where, in their opinion, such proposal poses an unacceptable threat to public health and/or water quality.

(Ord. No. NS-517.85, § 4, 11-26-13; Ord. No. NS-300.1002, § 35, 10-21-25)

(a) Engineering plans and site data for alternative OWTS shall be submitted in accordance with application procedures prescribed by the Director in the Onsite Systems Manual.

(b) Site evaluations, including soil profile inspection, percolation testing, and groundwater evaluation, shall be conducted in accordance with procedures in the Onsite Systems Manual.

(c) Engineering plans for alternative OWTS shall be prepared and signed by a California Registered Civil Engineer, Professional Geologist, or Registered Environmental Health Specialist who is knowledgeable and experienced in the field of onsite wastewater treatment and dispersal. The designer shall also be responsible for inspection of system installation to assure conformance with approved plans, and shall provide an "As-Built" drawing of the installation to the Director and property owner. The construction inspection by the designer shall be in addition to standard County inspection work carried out in accordance with provisions of Section B11-81 of this Chapter and any additional standards in the Onsite Systems Manual.

(d) Engineering plans will be reviewed by the Director and, where warranted, the Director may refer the plans to the applicable California Regional Water Quality Control Board staff and/or external third-party consultant(s) for additional review, the costs for which would be the responsibility of the applicant.

(e) Installation permits issued for alternative OWTS are subject to the same expiration and extension time frames as specified in section B11-77 of this Chapter for conventional systems.

(Ord. No. NS-517.85, § 4, 11-26-13; Ord. No. NS-300.1002, § 35, 10-21-25)

(a) In addition to an installation permit, an operating permit is required for all alternative OWTS, including those installed in connection with the repair or upgrade of existing OWTS as well as those for new construction. General requirements pertaining to operating permits are as follows:

(1) The operating permit will be issued by the Director following:

a. Completion of construction of the alternative OWTS;

b. Satisfactory compliance with the installation permit requirements; and

c. Payment of applicable fees. Operating permits are non-transferable.

(2) After initial issuance, the operating permit is required to be renewed periodically, the standard renewal period being one year. The Director may establish conditions allowing the time period between renewals to be extended for certain types of OWTS based on a record of favorable performance or other factors warranting a reduction in system oversight by the Department. Provisions for adjusting the operating permit renewal period shall be prescribed by the Director in the Onsite Systems Manual. Operating permits must also be renewed at the time of change in property ownership.

(3) Operating permits are intended to serve as the basis for verifying the adequacy of alternative OWTS performance and ensuring on-going maintenance. Permit conditions shall include monitoring and inspection requirements, permit duration, and other provisions as prescribed by the Director in the Onsite Systems Manual or as deemed appropriate by the Director on a case-by-case basis.

(4) Renewal of an operating permit requires:

a. Payment of the applicable fees, upon receipt of notice from the Director; and

b. Submission of the results of required system inspection and monitoring.

(5) Failure to pay the required fee or submit the specified monitoring and inspection information, or failure to undertake any required corrective work specified by the Director may be cause for issuance of a citation, penalty fees, non-renewal and/or revocation of the operating permit by the Director. The Director may place a lien on the property for recovery of any associated abatement costs and unpaid fees.

(6) A certified copy of the following shall be recorded against the property in the office of the County Recorder of Santa Clara County:

a. Initial operating permit issued for the system;

b. Reissuance of operating permit to new owners; and

c. Notices of withdrawal of any operating permit.

(b) Other uses of operating permits. An operating permit may also be utilized for circumstances other than alternative OWTS, such as for larger flow OWTS (> 2,500 gpd), in connection with holding tank exemptions or where, in the opinion of the Director, the type, size, location, or other aspects of a particular OWTS installation warrant the additional level of oversight provided by an operating permit. In such cases, the issuance and scope of operating permits will be issued in accordance with the general requirements listed in Section B11-92(a)(1) through (a)(6) above, and any additional requirements prescribed by the Director in the Onsite Systems Manual for particular circumstances.

(Ord. No. NS-517.85, § 4, 11-26-13; Ord. No. NS-300.1002, § 35, 10-21-25)

(a) A monitoring program will be established for each alternative OWTS as a condition of the operating permit at the time of permit issuance, and may be amended at the time of permit renewal. Said monitoring shall be performed to ensure that the alternative OWTS is functioning satisfactorily to protect water quality and public health and safety. The monitoring program will be in accordance with guidelines in the Onsite Systems Manual and may also incorporate recommendations of the system designer, manufacturer, or third-party reviewer.

(b) Monitoring requirements will vary depending upon the specific type of alternative OWTS in accordance with guidelines in the Onsite Systems Manual.

(c) The required frequency of monitoring will be in accordance with guidelines in the Onsite Systems Manual. Monitoring frequency may be increased if, in the opinion of the Director, system problems are experienced.

(d) Monitoring of alternative OWTS shall be conducted by or under the supervision of one of the following:

(1) Registered Civil Engineer;

(2) Professional Geologist;

(3) Registered Environmental Health Specialist; or

(4) Other onsite wastewater maintenance provider registered with the Department and meeting qualifications as established in the Onsite Systems Manual. Registration shall entail:

a. Documentation of required qualifications;

b. Participation in annual training/review conducted by the Director; and

c. Payment of an annual fee established by the Board of Supervisors.

Additionally, the Director may require third-party or County monitoring of any alternative OWTS where deemed necessary because of special circumstances, such as the complexity of the system or the sensitive nature of the site. The costs for such additional monitoring would be the responsibility of the owner.

(e) Monitoring results shall be submitted to the Director in accordance with reporting guidelines provided in the Onsite Systems Manual. The monitoring report shall be signed by the party responsible for the monitoring. Notwithstanding formal monitoring reports, the Director shall be notified immediately of any system problems observed during system inspection and monitoring that threaten public health or water quality.

(f) In addition to regular inspection and monitoring activities, post-seismic inspection and evaluation of alternative OWTS located in high-risk seismic areas will be required in the event of an earthquake causing significant ground shaking in the region, as determined by the Director in consultation with the County geologist. The Director will be responsible for issuing appropriate notices when such inspections are required; those conducting the inspections will be required to report the inspection results to the Director. The purpose of such inspections will be to assess and document any damage to the OWTS and to implement corrective measures, as needed, in a timely manner. Post-seismic inspection shall be in accordance with requirements prescribed by the Director, in consultation with the County geologist, and contained in the Onsite Systems Manual.

(g) The Director will, from time-to-time, compile and review monitoring and inspection results for alternative OWTS and, at least every two years, will provide a summary of results to the San Francisco Bay and Central Coast Regional Water Quality Control Boards. Based on this review, the Director may require corrective action for specific properties or certain types of alternative OWTS, or general changes in monitoring and inspection requirements.

(Ord. No. NS-517.85, § 4, 11-26-13; Ord. No. NS-300.1002, § 35, 10-21-25)

(a) Alternative treatment systems. Alternative treatment systems may be used to produce higher quality of wastewater effluent beyond that provided by a conventional septic tank and improve the performance of and siting options for the dispersal system. The following alternative treatment systems (also termed "supplemental" treatment) may be approved for use in Santa Clara County subject to compliance with the siting and design criteria specified in this Section and the Onsite Systems Manual:

(1) Intermittent and recirculating sand filters;

(2) Proprietary treatment units that provide secondary or better effluent quality; or

(3) Other alternative treatment systems approved by the Director and the appropriate California Regional Water Quality Control Board(s).

(b) Alternative dispersal systems. The following alternative dispersal systems may be proposed for use in Santa Clara County subject to compliance with the siting and design criteria in the Onsite Systems Manual:

(1) Shallow pressure distribution trench;

(2) Mound;

(3) At-grade;

(4) Pressure-dosed sand trench;

(5) Raised sand filter bed;

(6) Subsurface drip dispersal; or

(7) Other alternative dispersal systems approved by the Director and appropriate California Regional Water Quality Control Board(s).

(Ord. No. NS-517.85, § 4, 11-26-13; Ord. No. NS-300.1002, § 35, 10-21-25)

All requirements specified in Section B11-67 of this Chapter for conventional OWTS also apply to alternative OWTS, except as specified below. Design and construction of alternative OWTS shall be in conformance with requirements in the Onsite Systems Manual.

(a) Horizontal setbacks. Horizontal setback requirements for alternative treatment systems are the same as those specified in this Section B11-67 of this Chapter for septic tanks. Horizontal setback requirements for alternative dispersal systems are the same as those specified in Section B11-67 of this Chapter for conventional dispersal systems.

(b) Areas of flooding. Alternative OWTS shall not be located in areas subject to flooding as defined by the limits of the ten-year floodplain, determined or estimated from published floodplain maps or on the basis of historical evidence acceptable to the Director. Alternative OWTS shall be located and designed to avoid contamination of or damage from inundation by floodwaters during a 100-year flood event. As appropriate, such measures shall include:

(1) Protecting OWTS supplemental treatment, pressure distribution, and/or drip dispersal components from flood damage using structural tie-downs and/or elevating critical components above the 100-year flood level;

(2) Preventing discharge of wastewater into flooded dispersal areas from pump systems (e.g., using flood-activated float switches to override/disable pump operation during high water conditions); and

(3) Providing additional emergency storage capacity for flood periods.

(c) Ground slope. Maximum ground slope for different types of alternative wastewater dispersal systems are as follows:

Maximum Ground Slope for Alternative Wastewater Dispersal Systems 1

1 Related Requirements. Any disposal system located on a slope greater than 20 percent shall require the completion and approval of a geotechnical report per Section B11-83 of this Chapter.

(d) Vertical separation to groundwater. Where alternative OWTS are used, minimum vertical separation distance to groundwater, measured from the bottom of the dispersal system to the seasonal high water table, may be reduced from the requirements that apply to conventional OWTS (per Section B11-67 of this Chapter), as specified in the table below. Design requirements for alternative OWTS in the Onsite Systems Manual may impose additional restrictions on permissible groundwater separation distances based on system size (i.e., volume of wastewater flow) or for particular site conditions or geographic locations.

Minimum Vertical Separation Distance to Ground Water for Alternative OWTS (feet) 1

1 Measured from the bottom of the dispersal system to the seasonal high water table.

(e) Soil depth. Minimum depth of permeable soil beneath the bottom of the dispersal field shall be as specified in the table below for different types of alternative OWTS. Permeable soil is defined as having a percolation rate of 120 minutes per inch or faster or having a clay content of less than 60 percent, and shall not include solid rock formations or those that contain continuous channels, cracks or fractures. Design requirements for alternative OWTS prescribed in the Onsite Systems Manual may impose additional soil depth requirements based on system size (i.e., volume of wastewater flow) or for particular site conditions or geographic locations.

Minimum Soil Depth Beneath Alternative OWTS (feet) 1

1 Measured from the bottom of the dispersal trench, bed or piping (drip dispersal only).

(Ord. No. NS-517.85, § 4, 11-26-13; Ord. No. NS-300.1002, § 35, 10-21-25)

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