1. (a) Location.

   1. (1) Potable water storage tanks shall be located above ground water level unless otherwise approved in writing by the Department of Health.
   2. (2) The location must be such that surface water and underground drainage will be away from the structure.
   3. (3) They shall not be placed in close proximity to any sewer, privy, septic tank, absorption field, or other source of pollution from which either surface or underground drainage might flow toward the storage tank.
   4. (4) The minimum distances from any sources of pollution shall be in accordance with 20 CAR § 140-107(a).
   5. (5) Any sewer located within one hundred feet (100’) of any storage tank that has a portion which is located below grade should be constructed with water-tight mechanical joints.

2. (b) Drainage.

   1. (1) All potable water storage tanks shall be protected against flooding.

   2. (2) The ground surface shall be:

      1. (A) Sloped to drain or divert surface water away from the storage tank; and
      2. (B) So graded that no surface water will pool within the vicinity of the storage tank.
   3. (3) Floors of passageways, galleries, or compartments adjacent to any potable water storage tank shall have free drainage to the surface of the ground or into a drainage pit equipped with proper drainage pumps of ample capacity which are properly maintained.

3. (c) Overflows.

   1. (1) Overflow pipes shall discharge freely at least twelve inches (12”) above ground or flood level or into an open basin from a point not less than twelve inches (12”) above the top of spill line of the basin.
   2. (2) They shall be protected against backflow.

   3. (3) The overflow outlet shall be turned downward or to the side, and protected to prevent the entrance of:

      1. (A) Rain;
      2. (B) Dust;
      3. (C) Birds;
      4. (D) Insects;
      5. (E) Rodents; or
      6. (F) Other contaminating material.

4. (d) Design and operation.

   1. (1) Sufficient useable storage shall be provided with consideration given to average daily demand, peak hourly demand, power outages, and fire flows, if applicable.

   2. (2) Particular care shall be taken to ensure that construction joints are:

      1. (A) Water tight; and
      2. (B) Free of any material likely to deteriorate or fail due to weathering.
   3. (3) Storage tanks shall be kept free from cracks.
   4. (4) All inlet and outlet pipes shall be properly supported and shall be provided with a flexible joint, or equal, to prevent cracking the pipe if unequal settlement should occur.
   5. (5) Wall castings shall be provided with suitable collars to ensure watertight connections.
   6. (6) All potable water storage tanks shall be designed, inspected, repaired, and painted in accordance with the latest edition of the applicable AWWA standards.
   7. (7) A routine maintenance program, including regular cleaning and painting, shall be applied to all potable water storage tanks.
   8. (8) All leaks shall be promptly repaired.

5. (e) Covers.

   1. (1) Suitable and substantial covers shall be provided for all potable water storage tanks.

   2. (2) They shall be:

      1. (A) Water tight and of some permanent material; and
      2. (B) Constructed so as to:

6. (i) Provide drainage away from the cover; and

   1. (ii) Prevent the entrance of contamination.
   2. (3) The surface of covers shall not be used for any purpose in connection with which contamination material is likely to be produced.

7. (f) Manholes.

   1. (1) Manhole openings shall be fitted with:

      1. (A) Raised water-tight walls projecting at least four inches (4”) above the surrounding surface, with a solid water-tight cover with edges projecting downward at least two inches (2”) around the outside frame; or
      2. (B) A gasketed, weather-tight cover.

   2. (2) The manhole covers:

      1. (A) Shall be provided with a sturdy locking device; and
      2. (B) Should be kept locked at all times except when actually in use.

8. (g) Vents and other openings.

   1. (1) Any necessary vents or opening through covers of storage tanks for water-level control gauges or other purposes shall be constructed so as to prevent the entrance of:

      1. (A) Dust;
      2. (B) Rain;
      3. (C) Birds:
      4. (D) Insects; and
      5. (E) Any other material that might include contamination.
   2. (2) Any such opening shall be provided with a pipe sleeve or other device making a watertight junction with the storage tank cover and extending without openings to at least twelve inches (12”) above the surface of the cover with a stuffing box at the top.
   3. (3) No such vents or openings shall be provided near sources of dust, smoke, and the like nor where surface water might splash into them.
   4. (4) Vents must be protected with a twenty-four mesh screen.

9. (h) Cleaning and disinfection.

   1. (1) Potable water storage tanks shall be cleaned as often as necessary.
   2. (2) They shall be effectively disinfected before being placed into service in accordance with the "American Water Works Association Standard for Disinfection of Water Storage Facilities" (the latest edition of AWWA C652-11 or the latest revision thereof).
   3. (3) Before the storage tank is placed in service, two (2) consecutive series of samples that are not collected on the same day must show that the water is bacteriologically safe for drinking purposes.

Codification Notes: "AWWA" means American Water Works Association.