General provisions.

(a) Requirement for soil test. A soil test, performed in accordance with this Subchapter, shall be used to identify the dispersal site for all modifications to on-site sewage treatment systems and/or to identify the dispersal site and size the dispersal field for new installations of on-site sewage treatment systems except for: (1) lagoons; and (2) aerobic treatment systems that utilize spray irrigation when sized for Group 5 soil in the corresponding net evaporation zone. (b) Required credentials. Soil tests may only be performed by Professional Engineers, Professional Land Surveyors, Professional Sanitarians or Professional Environmental Specialists registered to practice in Oklahoma or Soil Scientists as defined in 27A O.S. 'Section(s) 3-1- 103(20). Additionally, an individual performing soil profile descriptions must also be either: (1) an Environmental Specialist for the DEQ and authorized by DEQ to perform soil profile descriptions; or (2) certified by the DEQ to perform soil profile descriptions. (c) Submission of soil test results to the DEQ. When a soil test is required, the results shall be submitted to the local DEQ office on DEQ Form 641-581P or 641-581SP or in a format approved by the DEQ. (d) Verification of design. If there is reason to believe soil test results submitted to DEQ are inaccurate or that there is water saturated soil or soil impervious to boring in any of the test holes at any depth up to thirty-six inches (36"), the system design may be verified by the DEQ. If the results of the verification contradict the proposed design of the system, the DEQ may perform a soil profile description to design the system. Soil tests conducted by DEQ shall supersede the results of any prior soil test completed in the same proposed dispersal site. (e) Fill areas and excavation. If there has been a fill of more than six inches (6") of soil or any excavation over an identified dispersal site, the local DEQ office must be contacted to determine 6 if an additional soil test is needed. Soil tests shall not be performed in major earth fill areas.