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Standards and Procedures for the Repair and Upgrade of Septic Systems

This web page is your starting point to learn about the standards and procedures to be followed in repairing a septic system in Santa Cruz County, including upgrades of existing systems to meet the septic system requirements for building additions and remodels. It is intended for use by contractors, consultants and property owners and applies to residential and commercial properties that are already developed. The requirements, procedures and guidelines contained herein are based on Chapter 7.38 of the Santa Cruz County Code and this document is specifically prepared pursuant to section 7.38.095.E. Parcels that have new development served by a septic system that was installed according to the requirements in Chapter 7.38 that became effective December 10, 1992, shall be ineligible to utilize the allowances for repairs described in Section 7.38.095.B for the purposes of upgrading the system to allow bedroom additions or additions of more than 500 square feet. Systems on parcels that were developed after September 16, 1983 must comply with the provisions of the Regional Water Quality Control Board's Basin Plan (Resolution 83-12).





Nonstandard Systems

If a parcel cannot meet all of the requirements for a Standard System described in Section I above, septic system repairs must be made using a Limited Expansion System, a Low-Flow System, Haulaway System, Alternative System, or Enhanced Treatment System. All of these are considered Nonstandard Systems. Parcels with Limited Expansion, Low-Flow, or Haulaway Systems cannot receive approval for building permits to add more than a one time addition of up to 500 sq. ft. of conditioned floor area that does not increase bedrooms or discharge. Under many circumstances, the conditions which prevent a parcel from meeting requirements may be overcome using an Alternative system and in that case bedroom additions may be allowed (see section II.D). Systems for parcels with soils that percolate faster than 1 MPI or slower than 120 MPI can only be approved if an acceptable proposal is submitted that complies with the requirements in the Alternative Systems section (Section II.D).

Parcels served by nonstandard systems are subject to recordation of a notice of nonstandard system and payment of an annual charge to cover the cost of inspection and monitoring of system performance, as discussed below under Section E.


Limited Expansion Systems are conventional systems which meet all requirements except for any one of the following:

  • Groundwater separation below the leachfield is between 1 and 3 feet at least 90% of the year and the system is over 250 ft. from a waterbody.
  • Less than 100% expansion area is available.
  • Water conservation measures must be installed, as specified below under Low-Flow Systems. All other Nonstandard system requirements must be met, except that the annual inspection fee will be waived if there is no indication of system problems.


Low-Flow Systems are conventional systems which meet all requirements except for any one of the following:

  • Only 50-99% of the required amount of leachfield area can be installed.

  • The system requires effluent pumping, but the pump chamber is less than required size.

Owners of parcels that elect to apply for a permit to install a Low-Flow System shall submit a proposal to install as much leachfield as possible that meets the requirements in section I.B.4 above. A permit for a Low-Flow system can only be approved if at least 50% of the leachfield

required for a Standard system can be installed. A proposal for an Alternative system or Haulaway System must be submitted by the owner if less than 50% of the required leachfield can fit on the parcel.

The following water conservation measures and provision for seasonal haulaway shall be made part of all Low-Flow System proposals.

1. Water Conservation Measures Required - All proposals for Limited Expansion and Low-Flow Systems shall include a requirement to install the water conservation devices described below if they are not already installed. These devices must be installed and inspected prior to permit final sign off.

a. All toilets shall be 1.6 gallon, or less, flush toilets.

b. Low flow shower heads of 2.5 gallons per minute, or less, shall be installed in all showers.

c. Water conservation aerators shall be installed on all lavatory, kitchen sink, and other household faucets.

d. Garbage grinders shall be removed.

2. Seasonal Haulaway Required as Necessary to Prevent System Failure -

All proposals for Low-Flow systems shall include a requirement that the septic tank will be pumped as necessary to prevent any failure or overflow of the septic system. A gate valve on the septic tank effluent pipe is required to be installed prior to final inspection. This valve will prevent wastewater from escaping from the tank and will also prevent groundwater from entering the tank. If the existing septic tank allows groundwater to leak into the tank, a watertight septic tank shall be installed. A violation reinspection fee will be assessed if the system is observed to fail.


Where less than 50% of the leachfield required in section I.B.2 can be installed on a parcel where the existing wastewater disposal system is failing or intermittently failing, a Haulaway System shall be utilized. Extreme water conservation measures should be utilized by the resident. Ultra low-flow toilets (0.5 gallons or less per flush) will be required. A watertight holding tank shall be installed if the existing septic tank cannot be made watertight. A holding tank high water warning alarm shall be installed. Any available leaching area may be used for greywater disposal if greywater disposal requirements are met. All blackwater effluent must drain to the holding tank. Blackwater may be discharged to the leachfield during periods when groundwater separation requirements are met. Risers must be installed in the leachfield and in the vicinity of the leachfield to monitor groundwater level. Records of septic tank pumpings must be made available for inspection purposes.


The owner of a parcel that cannot meet the requirements for a Standard System has the option described above to utilize a Limited Expansion, Low-Flow, or Haulaway System. However, if those options are selected, building additions are quite limited due to the limited sewage disposal capacity of the parcel. The resident may incur considerable cost and inconvenience due to the substandard system and the requirement for seasonal haulaway. The Alternative system program permits the use of various wastewater treatment and disposal technologies that are not specifically described in Chapter 7.38 of the County Code. The design, installation and use of alternative treatment and disposal technologies may result in superior wastewater treatment and disposal for that parcel and may, depending on site specific conditions, permit building additions beyond that permitted for other Nonstandard Systems.

The following is a discussion of the alternative technologies currently approved for use in Santa Cruz County. Information is given regarding design and construction requirements for each of these technologies. A listing of the possible applications of each technology is presented subsequently.

1. APPROVED ALTERNATIVE TECHNOLOGIES (Detailed specifications for all these technologies are available in the Environmental Health Office.)



A mound system consists of a mounded leaching bed constructed above ground that receives effluent distributed over the entire bed by means of pumped pressure distribution piping system. Use of this type of system is suited for gently sloping parcels subject to prolonged periods of shallow groundwater. For septic system repairs or upgrades, the following specifications are required: The minimum mound body fill depth shall be 2 feet below the distribution bed. Minimum depth from the distribution bed to groundwater shall be 3 feet (5 ft. within 25-100 ft. of a waterway). Minimum depth from natural grade to impermeable strata shall be 2 feet.



Sand filters provide treatment of the septic tank effluent in order to maximize the application rate of effluent where leachfields are constructed in slowly percolating soils. Sand filters provide denitrification of septic tank effluent, and their use prior to effluent disposal in rapidly percolating sandy soils may reduce nitrate discharge by at least 50%, if designed and operated properly. Increased effluent treatment provided by sand filters also allows a reduction in the required groundwater separation to 1 foot and allows reducing leachfield size by 50% from the requirements for a Standard System.


Designs for alternative wastewater treatment and disposal technologies other than those mentioned above may be considered for approval as described in Section 7.38.182 of the County Code.




Whenever a parcel cannot accommodate the size of leachfield required by the soils found on the parcel, a sand filter may be used to increase the soil application rate for wastewater loading. The leachfield requirements listed in section I.B.2 may be reduced by 50% when a sand filter is used. Similarly, the application rates for commercial or institutional properties may be reduced by 50% by the treatment of septic tank effluent with a sand filter (grease traps may also be required for commercial/institutional parcels - see section I.A.1).



For soils percolating 60-120 MPI, the use of a sand filter or approved enhanced treatment system may permit the use of leachfields sized according to the requirements for 31-60 MPI soils. Additionally, leachfields may be installed deeper than 5 feet effective depth to a maximum of 10 feet effective depth provided that all setbacks are observed and the leachfields are installed as shallow as possible.

Soils that percolate slower than 120 MPI shall not be approved for leaching devices and must propose a haulaway system as described below.



Parcels that have gentle slopes and groundwater problems that prevent the use of conventional leachfields may be suitable for mound systems described above. A proposal for a mound system that meets requirements for the design loading rate may enable bedroom and other building additions provided that an area is available for replacement of the mound. Use of a sand filter or approved enhanced treatment system may also allow building additions with reduced groundwater separation.


d. ENHANCED TREATMENT - An Enhanced Treatment System is a system that utilizes special designs and/or additional technology to treat the effluent to a much higher level than a conventional system. The goal is to reduce BOD, Suspended Solids and Nitrogen each to less than 10 mg/l. (In the interim, technologies which meet the objective for BOD and Suspended Solids and provide at least 50% nitrogen removal may be accepted. In sandy soils, special designs which promote denitrification in or under the leachfield will also be considered.) Enhanced Treatment systems will be Alternative

Systems and may utilize higher application rates in the leachfield design if they meet the objectives for BOD and Suspended Solids removal (see Section II.D). Enhanced treatment systems may be used to treat effluent where soils percolate in the range of 60-120 MPI; they are required in the following circumstances:


(1) For systems in Sandy Soils in Water Supply Watersheds. Sandy soils are those soils identified by the US Soil Conservation Service as Zayante or Baywood Series, or other soils found in the field to have percolation rates faster than 6 MPI. In these soils, enhanced treatment shall be required for any new system and any system which will serve a bedroom addition, a remodel adding more than 500 square feet, or other expansion of use which will result in an increase in volume or strength of wastewater flow. Ultimately, enhanced treatment will likely be required for all repairs in sandy soils.

(2) For Large Systems which serve more than 5 residential units or which have peak daily flows greater than 2500 gallons per day and which are in the San Lorenzo Watershed or a designated Water Supply Watershed. For all new or replacement systems in designated areas, enhanced treatment shall be required.


The approval and use of a nonstandard system is subject to the "Procedures for Approving and Managing Nonstandard Sewage Disposal Systems" (Sewage Policy 16). These procedures are summarized below:


1. Acknowledgment of Requirements for Use of a Nonstandard System - Prior to approval of the permit application for a nonstandard system, the property owner must sign an Acknowledgment of Requirements for Use of a Nonstandard System prepared by EHS staff, in which the owner acknowledges and agrees to comply with all requirements for use of the nonstandard system, including: limitations on property use and water use, operation and maintenance requirements, recordation of a Notice of Nonstandard System on the property deed, annual compliance inspections by the County, and payment of an annual service charge on the property tax bill to cover the costs of inspections. The executed Acknowledgment and Requirements are attached as conditions of approval of the permit and continuing use of the system.


2. Notice of Nonstandard System - Once the nonstandard system is installed, the County shall record a Notice of Nonstandard System on the deed for the affected parcel. This will describe the type of system and its limitations (if any) and specify operating conditions, including annual reinspections by EHS of the system. This will replace the past procedure of requiring an operating permit for alternative systems.


3. Annual Inspection Fee - Property owners of Nonstandard systems that require annual reinspections by EHS personnel to insure correct system operation will be subject to an additional CSA 12 service charge on their property tax bill to pay for the cost of the inspections.


If any of the terms or conditions of an approved sewage disposal permit are not observed during the installation or operation of any septic system, and the owner fails to correct the problem after reasonable notice, the following enforcement action(s) may be exercised.


When a violation of requirements has been duly noticed to the owner of the parcel, any subsequent enforcement visits to the parcel shall cause a violation reinspection fee to be imposed for each visit to the parcel as authorized by Section 7.38.290 of the County Code.


A notice of violation describing the violation of the standard(s) contained in this document or in Chapter 7.38 of the County Code may be recorded against the parcel until the violation is abated.


If an individual contractor violates the requirements of this document or Chapter 7.38 of the County Code, a complaint will be filed with the State Contractor's Licensing Board.


December 30, 1992


Installation Procedure and Approved Models

A distribution box is used to divide the effluent flow from a septic tank into two or more leach tenches for soil absorption. Equal distribution is very important in order to take advantage of all of the available leaching area. Spreading the effluent dose over all parts of the system maintains a relatively low soil loading rate and provides better effluent treatment. Distribution boxes also provide a readily accessible means of locating the leaching device, making flow adjustments as needed, monitoring the disposal system, and making additions to the system.

Distribution boxes are typically made of reinforced concrete with plumbing "knock outs" into the box. The inlet must be higher than the outlets, with all outlets at the same level. The box must be large enough to accommodate the pipes and fittings used and still allow for flow adjustment. A sturdy gas-tight lid (and risers where appropriate) shall be provided that permits access from the surface. A list of approved manufacturers and distribution box model numbers is presented below.

The correct installation of distribution boxes requires proper planning and careful construction techniques. The location of the box(es) and associated plumbing, as well as the required elevations, must be worked out in advance. Grading of all portions of the system must be done with care such that the leach trench maximum allowable depth may be maintained. The distribution box(es) must be "wet set" on a pad of cement or grout on level undisturbed or mechanically compacted soil. All the outlet plumbing must be set into the box as level as possible with final flow adjustments made prior to final backfill. All piping must be resealed with grout. Environmental Health Service staff must perform an inspection that demonstrates that the flow out of the box has been properly adjusted as part of construction inspection for final system approval. Adequate water must be available at the site for the flow test.

Fine adjustments of flows to each leachfield shall be made as necessary to maintain the proper function of the distribution box. If any leachfield fails, a valve must be installed on the pipe from the distribution box to the leachfield and closed to stop the failure.




M. C. Nottingham Models: D-48 (5 exit ports)
  D-49 (3 exit ports)


Tom's Septic Tanks Septic tank with built-in "D" box
  And all separate "D" boxes
O.S.I. Hydrosplitter
Zabel Flow-divider