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Virginia Administrative Code
Title 12. Health
Agency 5. Department of Health
Chapter 640. Alternative Discharging Sewage Treatment Regulations for Individual Single Family Dwellings

12VAC5-640-450. Design criteria for the use of intermittent streams, dry ditches, or wetlands.

All owners of systems discharging to an intermittent stream, dry ditch, or wetland shall ensure the following conditions are met:

1. Direct contact between minimally diluted effluent and insects, animals, and humans must be restricted for the life of the system. This will be achieved by reducing the chance of ponding and run-off and limiting access to the effluent. The department shall require fencing, rip-rap, or other barriers to restrict access to effluent discharging to a dry ditch, intermittent stream, or wetland as deemed necessary to protect public health. This determination shall be made by the department on a case-by-case basis.

a. For dry ditch and intermittent stream discharges, the restricted access area shall begin at the point where the effluent is discharged and continue for 500 feet, until the effluent discharges into an all weather stream or is no longer visible during the wet season. The design shall provide justification for the length of the restricted access channel if less than 500 feet.

b. For wetland discharges, the restricted access shall extend for a distance of 250 feet along the flow path of the discharge unless a 10:1 dilution with the wetland can be achieved. If the flow path cannot be established and a 10:1 dilution cannot be obtained, then access shall be restricted for 100 feet radially from the point of discharge. For wetland discharges, the access barrier may be a subsurface discharge point, but in no case shall the discharge point and diffuser be greater than 18 inches below the natural wetland surface.

2. When effluent is discharged to a dry ditch, intermittent stream, or wetland, the owner shall own the land or acquire an easement from the downstream or downgradient land owner to discharge on all land below the point of discharge for the distance shown in Table 3.2. To allow for system construction and repair within the restricted access area, and to facilitate maintenance and monitoring, the easement shall be a minimum of 25 feet wide and approximately centered on the low point of the dry ditch or intermittent stream for the entire length of the restricted access area. For wetlands, the easement shall be measured radially from the point of discharge unless flow direction can be established. In those cases where flow direction can be established, the easement shall be a minimum of 25 feet wide and approximately centered on the discharge path and extend for a distance along the flow path as described in Table 3.2. If the slope across the discharge site is equal to or greater than 10%, the flow direction can be determined by observation. For slopes less than 10%, a site specific study must be conducted to document the direction of flow. All easements must be in perpetuity and shall be recorded by the owner with the clerk of the circuit court having jurisdiction over the property prior to issuance of the construction permit. For the purposes of complying with this chapter, written approval to utilize an easement owned by the Virginia Department of Transportation shall be recorded by the owner with the clerk of the circuit court office having jurisdiction over the property.

3. Each discharging system that discharges to a dry ditch, intermittent stream, or wetland must receive additional treatment beyond that required by the General Permit in order to reduce the increased potential for public health problems which may result when partially treated effluent is not diluted. Such additional treatment shall be capable of producing an effluent with a quality of 10 mg/l of BOD5, 10 mg/l of suspended solids and a fecal coliform level of less than or equal to 100 colonies per 100 ml. Treatment units approved as TL-3 are recognized as having the ability to meet this BOD5 and TSS standard, but have not been tested for compliance with the fecal coliform standard. Therefore, the following reliability classifications in Table 3.2 must be met when designing discharge systems intended to discharge into dry ditches, intermittent streams, or wetlands.


Reliability Class

Downstream or Down Channel Distance for Dry Ditches or Intermittent Streams (feet)

Wetlands from Discharge Point along Flow Path or Radially from Discharge Point

No spring below

Spring below

Reliability Class I

250 ft

1,500 ft

100 ft

Reliability Class II

500 ft

1,500 ft

250 ft

Statutory Authority

§§ 32.1-12 and 32.1-164 of the Code of Virginia.

Historical Notes

Derived from VR355-34-400 § 3.7, eff. July 30, 1992; amended, Virginia Register Volume 32, Issue 6, eff. December 16, 2015.

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