Sufficient potable water for the needs of the retail food store shall be provided from a source constructed, maintained, and operated according to 10 NYCRR Part 5 and 9 NYCRR Part 902. Except when used as specified in section 271-6.7 of this Subpart, water from a nonpublic water system shall be sampled and tested quarterly for microbiological contamination, annually for nitrate and once for nitrite in accordance with the requirements of the New York State Department of Health for a noncommunity water system, as set froth in 10 NYCRR section 5-1.52. The most recent sample report for the nonpublic water system shall be retained on file in the food establishment.