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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 590. Waterworks Regulations |
Section 430. Determination of surface water influence of groundwater sources
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All waterworks' groundwater sources utilized by waterworks such as wells, springs, and infiltration galleries shall be evaluated by the division to determine surface water influence. The waterworks owner shall provide to the division all necessary information to make this determination in accordance with the following three-step procedure. The source shall be subjected to all criteria in a stepwise fashion. Once a determination with regard to surface water influence has been made it is not necessary to continue to the next step:
1. Step one - source history.
a. The source is not surface influenced if the division has previously determined that disinfection treatment is not required (see 12VAC5-590-380 G).
b. The source is surface influenced if it has been directly associated with a biological waterborne disease outbreak such a Giardiasis, or if it has been directly associated with chemical contamination from the surface.
c. For all sources consisting of a spring, infiltration gallery, wells located in Karstian geology, or not classified as either 12VAC5-590-430 A 1 or 2 the determination shall proceed to step two.
2. Step two - source physiology and geology.
a. The source is not surface influenced if it consists of a properly constructed Class I or Class II well in non-Karstian geologic provinces of the state, with no history of turbidity fluctuations, and that have been determined by the division to be adequately treated by disinfection alone (12VAC5-590-380 G).
b. The source is surface influenced if a sanitary survey reveals that surface water may directly enter the source either through structural defects or through nearby surface water bodies, sinkholes, troughs, drainage ways, or other suspect geological features.
c. The determination for sources consisting of a spring, infiltration gallery, wells located in Karstian geology or otherwise not classified under 12VAC5-590-430 B 1 or 2 shall proceed to step three.
3. Step three - water quality.
a. The source is not surface influenced if the total coliform concentrations of the raw water as measured by the multiple-portion decimal-dilution (MPN) method is less than 100 organisms/100 mL based on a geometric mean of 20 or more samples over a period of six months with no more than 10% of these samples exceeding 100 organisms/100 mL; and having no record or confirmed fecal coliform contamination.
b. The source is surface influenced if:
(1) The source turbidity, temperature, pH, or conductivity fluctuate following climatic events or fluctuate relative to nearby surface bodies of water, or
(2) The source exhibits the presence of diatoms, rotifers, coccidia, plant debris, insect parts, or Giardia cysts as identified by particulate analysis.
Historical Notes
Derived from VR355-18-004.10 § 2.10, eff. June 23, 1993.