(1) Storage reservoirs shall be designed to:

(a) Prevent entry by birds, animals, insects, excessive dust, and other potential sources of external contamination;

(b) Include:

(i) A weathertight roof;

(ii) A lockable access hatch;

(iii) A screened roof vent;

(iv) An overflow pipe with atmospheric discharge or other suitable means to prevent a cross-connection;

(v) A sample tap;

(vi) A drain to daylight, or an alternative design approved by the department or health officer that is adequate to protect against cross-connection;

(vii) Tank isolation in order to perform maintenance procedures; and

(viii) Other appurtenances appropriate for the protection of stored water from contamination;

(c) Be above normal ground surface level. If the bottom elevation of a storage reservoir must be below normal ground surface:

(i) The storage reservoir must be placed above the groundwater table; and

(ii) The top of a partially buried storage reservoir must be at least two feet above normal ground surface.

(2) A Group B system designed to supply fire hydrants must have a minimum distribution main size of six inches (150 mm) supplying each hydrant.