Site plans for leach lines do not have to be done by an engineer unless they are required to be fully engineered. All commercial systems must be fully engineered. In general, residential systems do not require full engineering unless otherwise required by Environmental Health. Factors such as rock outcroppings, high ground water concerns, high slopes, area history, etc. may require a residential project to be fully engineered as determined by EH.

Engineered leach line plans shall be prepared by a Qualified Professional (QP) or by an individual under the supervision of a QP. The following are considered QP: A California Professional Geologist, a California Certified Engineering Geologist, a California Registered Professional Engineer, California Registered Professional Soil/ Geotechnical Engineer or a California Registered Environmental Health Specialist.

The following are requirements for a leach line application. Please address these points on the site plan and report.

• A percolation test is required for all leach line applications. Please refer to the information sheet titled “Percolation Test Requirements” for specifics.
• A site plan shall be included labeling the location of the following:
  • Location of and size of septic tank
  • Location and type of leach lines (standard, special, or infiltrator)
  • 100% expansion area
  • Location of distribution box
  • Location of residence(s) and number of bedrooms.
  • Commercial systems will require a floor plan showing the location of all fixture units
  • along with a drainage fixture unit list
  • Location of water well(s), if any, within 100 feet of septic system
  • Location of any geological features (i.e. large streams, trees, rock outcroppings, rivers, etc.)
  • All setbacks
  • Location of percolation testing
  • Cutout diagram of leach line
  • Proof that 15 feet to daylight principle can be met in sloping areas
• Three copies of site plan. If site plans are engineered they shall be signed and wet stamped by the engineer.
• Indicate soil type on report.
• Location of septic system shall be staked out prior to initial site inspection.
• Leach systems installed under concrete or asphalt require 25% additional leaching area
• Minimum 150 square feet of trench bottom shall be provided for each leach system (min. 50 ft of line)
• Maximum leach line length is 100 feet per line.
• Show calculations used to size leach system.
  • Ryon method may be used for systems that are fully engineered.

Notes

• Leach systems in type 1 soil may not be allowed depending on geologic factors. Additional soil information may also be required and is determined on a case by case basis. Please contact Environmental Health for more information.
• Mound system or systems requiring import of soil will have to be engineered and a percolation test conducted on imported material
• Engineered plans require verification of no adverse geologic conditions (i.e. bedrock, groundwater) 7 feet below the bottom of the proposed trench
• Advanced systems which require pumps, dosing chambers, timers, mechanical parts, etc. shall be engineered.
• Plans are valid one year from the date of approval.