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									      Land Use Program
   Septic System Overview
        Scott Weldon
         619 441 4086
scott.weldon@sdcounty.ca.gov
Definition of “Septic System”
 A subsurface sewage disposal system which uses a
  combination of a septic tank and a effluent dispersal
  mechanism.
 A two-chamber septic tank is used to accumulate solid
  matter. The solid matter is decomposed by anaerobic
  bacteria. Clear effluent then passes to the dispersal
  mechanism, which may be leachlines or seepage pits.
 Septic tanks need to be pumped at least once every
  four years to remove solids.
Septic Systems are required for
plumbed structures anywhere
there is no public sewer
 If public sewer is not within 200’ of a vacant
  lot that is proposed to be built out, the owner will
  need to install a septic system that is permitted
  and inspected by the County of San Diego,
  Department of Environmental Health.
 The intent of a properly designed septic system
  is to keep sewage underground for at least 25
  years.
Map of San Diego County
 Percolation tests for septic systems
Percolation tests must be completed
   to determine soil permeability.
 Consists of at least four 6” diameter borings
  in the proposed leachline/ pit area.
 Must be completed by a licensed
  professional, and must follow County Policy
  for percolation test procedures.
 A deep boring is also required to verify
  adequate soil depth and adequate separation
  to groundwater . Deep borings are 15’-20’
  deep.
 Soil Permeability

 Soil must be able to accept water over time in
  order for a septic system to work properly.
 Clay soils have poor percolation rates, and may
  not support a septic system.
           Groundwater Protection
              requirements
   5’ separation required from leachlines to groundwater.
   10’ separation required from Horizontal or Vertical Seepage Pits
    to groundwater.
   100’ setback required from any portion of a septic system to a
    water well.
   100’ setback required from a septic system to a year-around
    stream
   50’ setback required from a septic system to a seasonal stream.
   ¼ mile setback required from a vertical seepage pit to any well
               Permit Process
1.   A percolation test or septic layout is submitted
     and is field reviewed by DEH staff. Project is
     either approved or disapproved. If it’s
     disapproved, the owner has 12 months to correct
     any issues / concerns.
2.   Grading must be completed prior to issuance of
     the septic permit (i.e. pad or driveway grading).
3.   A septic permit is then issued in order to install
     the system. The permit is valid for one year, and
     the system is inspected by the County at the time
     of installation.
Types of dispersal mechanisms
 Leachlines – trenches 3’– 5’ deep with 1-2” rock
  under and around 4” perforated pipe.
 Vertical Seepage Pits – 4’ diameter rock-filled
  pits. The bottom of the pit is kept at least 10’
  above groundwater. Vertical pits are only
  allowed in areas with poor quality groundwater
  (basically along the coastline where salt water
  intrusion has occurred) .
 Horizontal Seepage Pits – A series of 5’
  diameter rings that are 6’ tall. Soil must be very
  permeable (perc rate < 30 min per inch).
Surface discharge requirements
 All sewage effluent is to remain underground. If a
  septic system fails, the septic tank should be pumped
  as necessary to keep sewage underground until repairs
  can be made.
 A repair to a failing system usually consists of a 200’-
  300’ leachline addition to the existing leachfield.
 County Code requires a failing system to be repaired
  within 30 days.
Surface Discharge Requirements
(continued)
 Sediment control is important during the rainy
  season.
 When excavating on your property, all run-
  off/sediment is to be kept on your property by
  using sediment basins, berms and/or silt fences.
Reserve Requirement
 Each lot in San Diego County that has a septic
  system on it must have a designated area to
  replace the dispersal field should it fail. This
  area is known as the “reserve area”. No
  structures or hardscape may be placed in this
  area.
 The average life expectancy of a septic system
  is 25 years.
What can go into a septic tank?
 Domestic waste may go into a septic tank
 Industrial waste, solvents, pesticides or fertilizers
  should not go into a septic tank.
 The introduction of toxic materials into a septic
  tank will kill the biomat layer in the tank. The
  biomat layer then breaks up and goes into the
  leachline trenches, clogging the system up. This
  leads to premature failure.
Farm Labor Housing
 Currently, there is no fee for the Department of
  Environmental Health to review Farm Labor
  Housing proposals.
 The lot must be able to support the additional
  leachfield that will be required to accommodate
  the laborers in order for the Farm Labor Housing
  to be approved.
  Future of Septic Systems in
       San Diego County
State Assembly Bill 811
     Promulgated by the State Water Board.
     All Counties are to have standardized requirements for septic
     systems.
     “aerobic” septic tanks are to be the norm by 2007. Effluent
     quality will be increased significantly, however the cost of
     septic systems will triple ( from approximately $7,000 to
     $25,000).
     Separation requirement to groundwater will be reduced to 4’.
     “Alternative” systems will be allowed.
     All septic systems are to be certified annually that they’re
     operating correctly by 2007(state Water Board requirement).
          Alternative Systems
 An “alternative” septic system consists of an aerobic
  septic tank and a dispersal mechanism. (conventional
  systems use anaerobic septic tanks).
 Oxygen is added to the aerobic tank by various
  methods. The down-side to aerobic systems is that
  they have moving parts and require electricity. This
  opens the door to break-downs and/ or human error.
 The positive aspect is that effluent quality is
  exponentially better.
Alternative Systems (continued)

 Since effluent quality is better, it may be possible to
  reduce the size of the dispersal field. Sizing of
  alternative systems is in its inceptive stage, and is still
  being worked out..
 4’ separation to groundwater will be required.
Example of a Septic Tank
Tank tied to leachfield
Example of a leachline

								
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