Section 246-274-420 - Soil and site evaluation - Tier 2 and Tier 3 greywater irrigation systems(1) A soil and site evaluation is required for Tier 2 and Tier 3 greywater irrigation systems. Only qualified professionals or local health officers may perform soil and site evaluations. Soil scientists may perform soil evaluations.(2) The local health officer may allow a resident owner of a single-family residence, not adjacent to a marine shoreline, to perform the evaluation for his or her residence when the system reuses no more than three hundred gallons per day of greywater.(3) The person evaluating the soil and site shall:(a) Ensure that the soil types of the site are properly identified, and will provide suitable soil capable of supporting healthy plant life.(b) Determine texture, structure, compaction, and soil characteristics and classify the soil as in WAC 246-274-415, Table II.(c) Use the soil names and particle size limits of the United States Department of Agriculture Natural Resources Conservation Service classification system.(d) Provide a report to the local health officer that includes: (i) A soil map showing the soils within the project site. If the original, undisturbed soil will be augmented with additional soil, include a description of the additional soil, how it will be tilled into the original soil, and how the resulting soil will meet the requirements of WAC 246-274-415(7);(ii) The drainage characteristics of the site and those areas immediately adjacent to the site that contain characteristics impacting the design;(iii) The existence of designated flood plains and other areas identified in the local management plan required in WAC 246-272A-0015; and(iv) The location of existing features affecting system placement, including the items requiring setback, identified in WAC 246-274-405, Table I, and other features such as:(A) Surface water and storm water infiltration areas;(C) Outcrops of bedrock and restrictive layers;(D) Driveways, parking areas, and other impervious surfaces;(E) The approved on-site sewage system serving the building, if any; and(F) Underground utilities.Wash. Admin. Code § 246-274-420
Statutory Authority: RCW 90.46.015. 11-02-011, § 246-274-420, filed 12/28/10, effective 7/31/11.