5.1 This practice should be used as the initial step for evaluating a site for its potential to support an on-site septic system and to determine the best location for subsurface observations as covered in Practice D5921.

5.2 This practice should be used by individuals involved with the evaluation of properties for the use of on-site septic systems. Such individuals may be required to be licensed, certified, or meet minimum educational requirements by the local or state regulatory authority. Generally, such individuals should be familiar with the appropriate regulatory requirements governing the design and placement of on-site septic systems for the area of the site being investigated, and at least some experience or training in geomorphology, soils, geology, and hydrology.

5.3 This practice is one step in the design of an on-site septic system that also includes subsurface characterization, see Practice D5921, staking and protection of the soil absorption or constructed filter bed area, see Practice D5925, selection of system type, and design of the system size and configuration. Typically, the same individual will perform the surface and subsurface characterization of a site. Local regulation and practice will determine whether the same individual is responsible for all steps in the process of locating and designing an on-site septic system. Effective surface and subsurface characterization of a site for on-site septic systems, however, requires some knowledge of the following for the county or state in which the site is located: (1) on-site septic system types typically used for different soil conditions, and (2) typical soil absorption/filter bed areas required for different wastewater flow rates and areal soil wastewater loading rates.

1.1 Site characterization of surface conditions at a site for evaluating suitability for on-site septic systems requires both simple and complex techniques that may be accomplished by many different procedures and may be variously interpreted. These studies are frequently site specific and are influenced by geological and geographical settings, by the purpose of the site characterization, by design requirements for the project proposed, and by the background, training, and experience of the staff involved.

1.2 This standard is a guide for using the surface site characterization for on-site septic systems method for projects that require on-site sewage disposal. It is intended to improve consistency of practice and to encourage the use of this method as part of a site characterization program. Since the subsurface conditions at a particular site are usually the result of a combination of natural, geologic, topographic, and climatic factors, and of historical modifications both natural and manmade, an adequate and internally consistent use of a method as part of the exploration program will allow evaluation of the results of these influences.

1.3 This practice can be used at any site where on-site treatment of residential and nonhazardous commercial wastewaters using septic tanks and natural soils or constructed filter beds is required or an option under consideration. This practice may also be useful when constructed wetlands are used as an alternative wastewater treatment method.

1.4 This practice should be used in conjunction with Practices D5921 and D5925.

1.5 Units—The values stated in either SI units or inch-pound units given in brackets are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. Reporting of results in units other than SI shall not be regarded as nonconformance with this standard.

1.6 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.