Roles and responsibilities: On-site wastewater design professionals

General areas of responsibility

A practicing on-site wastewater design professional:

• Performs services for new construction of a system.
• Evaluates existing on-site disposal systems.

Subjects typically addressed by on-site wastewater design professionals

The following examples are general guidelines, and shouldn't be considered all inclusive.

Design area	Subjects addressed by on-site wastewater design professionals
Site evaluation	Existing site and system conditions Potable water source and utilities Topography and property information Surface water, ground water, and drainage
Evaluation of soil	Soil logs, sampling, and classifications Impervious layers and seasonal water table Fill areas and other adverse soil conditions
Design	Type of disposal system System components and operational parameters
Construction management	Disposal site preparation Construction conformance with design Report construction and site variances Operational testing and owner use

Definitions

• On-site wastewater design defined: RCW 18.210.010 (8)
• On-site wastewater treatment system defined: RCW 18.210.010 (9)

Questions?

Email us: DFCcompliance@dol.wa.gov