Civil-Environmental Engineering

Frequently Asked Questions*

3) When should an engineer become involved in planning a septic system?


Most counties require an engineer (or certified designer) be involved when:

  • A standard gravity system's primary and replacement fields will not fit on the property.

  • A standard gravity design would put the bottom of the laterals deeper than 5' (requiring a pumped system).

  • High groundwater or a shallow impermeable layer is present.

  • The flow rate or the BOD level is beyond that of a typical household or is unknown.

  • The field's location is uphill or a long distance from the tank (i.e. a pump is required).

  • ​Slope instability or significant on-to-site storm water flow is suspected.

  • Site is located in a 100 year flood zone.

*The following page is a summary for quick reference only and may not represent the latest standards.  For complete and up-to-date information, see each counties official website.