12VAC5-610-1170. Cisterns.
A. General. Cisterns shall be considered only when no other source of potable water is feasible.
B. Location and protection. The following precautions should be taken with regard to the location and protection of cisterns:
1. The distance from other sources of pollution shall be the same as for subsurface soil absorption systems contained in Table 4.4 and 12VAC5-610-810 A; and
2. Cisterns shall be located in a manner that will not subject them to flooding.
C. Construction.
1. The cistern shall be constructed of watertight, durable, structurally sound material, with a smooth interior surface.
2. When the cistern is filled by rainfall provisions shall be made to bypass, divert or otherwise remove the water that falls at the beginning of a rain.
3. Cisterns shall be accessible for cleaning.
4. Where a manhole cover is used, it shall be watertight and the manhole shall be at least 24 inches in diameter.
5. Where another type of cover is used, it shall be a solid, watertight cover which overlaps the framed opening and extends vertically down around the frame at least two inches.
6. The top of the cover frame shall be at least 12 inches above the surrounding ground surface.
7. All openings into the cistern shall be screened in order to prevent the entrance of insects, rodents and other animals and pollutants.
8. When screens and filters are utilized for filtering roof runoff, they shall be accessible for regular cleaning.
9. Drain and overflow pipes shall not be connected directly to any sewer, soil pipe, house drain or other waste pipe. An air-gap shall be provided on all drains and overflow pipes. Drains and overflow pipes shall be suitably screened.
10. Asphaltic roofing material or painted roofs should not be utilized in conjunction with cisterns because of the potential leaching of toxic materials.
D. Potability. Cisterns cannot be relied upon to provide potable water without adequate treatment. Adequate treatment consists of removal of solids washed from the roof and continuous disinfection.
Statutory Authority
§§ 32.1-12 and 32.1-164 of the Code of Virginia.
Historical Notes
Derived from VR355-34-02 § 4.52, eff. February 5, 1986; amended, eff. May 11, 1988.