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Virginia Administrative Code (Last Updated: January 10, 2017) |
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Title 12. Health |
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Agency 5. Department of Health |
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Chapter 610. |
Section 594. In-ground systems
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A. An in-ground system is a system which utilizes a natural, undisturbed soil horizon to treat and disperse effluent where the infiltrative surface is placed 18 inches or more beneath the original surface of the ground. In-ground systems include, but are not limited to, conventional septic tank drainfield systems, chamber systems, alternative aggregate systems, enhanced flow systems, and pressure dosed systems.
B. Septic tank effluent. Septic tank effluent may be utilized in an in-ground system when all of the site and soil criteria of this subsection are met. Also see Table 4.3.
1. Horizon. The soil horizon(s) for the 18 inches immediately below the installation depth shall not show the presence of any limiting factor. Limiting factors include bedrock, seasonal or permanent water table, pans, or other impervious strata.
2. Separation distances. Table 4.2 contains the minimum setback distances between an absorption field and various structures or topographic features.
3. Estimated or measured infiltration rates. The estimated or measured infiltration rate shall not exceed 120 minutes per inch within any part of the sidewall area of the trench or within 18 inches of the infiltrative interface where effluent encounters undisturbed soil.
C. Soil criteria when utilizing secondary effluent. Secondary effluent may be utilized in an in-ground system when all of the criteria of this subsection are met. Also see Table 4.3.
1. Horizon. The soil horizon(s) for the 12 inches immediately below the installation depth shall not show the presence of any limiting factor. Limiting factors include bedrock, seasonal or permanent water table, pans or other impervious strata.
2. Separation distances. Table 4.2 contains the minimum setback distances between an absorption field and various structures or topographic features.
3. Estimated or measured infiltration rates. The estimated or measured infiltration rate shall not exceed 120 minutes per inch within the sidewall area of the trench, if any, or within 12 inches of the infiltrative interface where effluent encounters undisturbed soil.
Historical Notes
Derived from Volume 16, Issue 16, eff. July 1, 2000.