If a public water system has fewer than five drinking water taps that can be used for human consumption and that meet the sample site criteria of subparagraph (1)(iii) of this subdivision to reach the required number of sample sites listed in the following table, the system may collect at least one sample from each tap and then collect additional samples from those taps on different days during the monitoring period to meet the required number of sites; or, with written State approval, collect fewer samples provided that all taps that can be used for human consumption are sampled. The State must approve this reduction of the minimum number of samples in writing based on a request from the system or onsite verification by the State. The State must specify sampling locations when a system is conducting reduced monitoring. A public water system may also apply to the State in writing to substitute non-first-draw samples. Such systems must collect as many first-draw samples from appropriate taps as possible and identify sampling times and locations that would likely result in the longest standing time for the remaining sites.
Population Served | Standard Monitoring | Reduced Monitoring |
Number of Sites | Number of Sites | |
>100,000 | 100 | 50 |
10,001 to 100,000 | 60 | 30 |
3,301 to 10,000 | 40 | 20 |
501 to 3,300 | 20 | 10 |
101 to 500 | 10 | 5 |
<100 | 5 | 5 |
Required samples shall be collected during six-month monitoring periods, beginning January 1st or July 1st of each calendar year.
Upon written approval from the State, any water system that has optimal corrosion control treatment installed that meets the lead action level and maintains the range of values for the water quality control parameters reflecting optimal corrosion control treatment during three consecutive years of monitoring may reduce the frequency of monitoring for lead and copper from annually to once every three years. Samples collected once every three years shall be collected no later than every third calendar year.
The results of any monitoring conducted in addition to the minimum requirements of this section shall be considered by the system and the State in making any determinations (i.e., calculating the 90th percentile lead or copper level) under sections 5-1.40 through 5-1.48 of this Subpart.
The State may invalidate a lead or copper tap water sample if one of the following conditions is met:
If a sample is invalidated, it does not count toward determining lead or copper 90th percentile levels or toward meeting the minimum monitoring requirements for that system. To invalidate a sample, the decision and the rationale for the decision must be documented in writing. The system shall submit to the State, for invalidation determination, the results it believes should be invalidated along with supporting documentation and the rationale for supporting invalidation of the samples. If after invalidation of sample results, the system has too few samples to meet minimum sampling requirements, replacement samples shall be taken as soon as possible, but no later than 20 days after invalidation or by the end of the applicable monitoring period, whichever is later. Replacement samples apply only to the monitoring period associated with the original sample, and shall be taken from the same location. If resampling from the same location is not possible or the sample site was invalidated, the resample may be taken from other sites in the sampling pool not already used for sampling during that monitoring period.
Any water system that serves 3,300 or fewer persons and meets the criteria in this subdivision may be eligible for a waiver to reduce monitoring of lead and copper to once every nine years (full waiver), or only for lead, or only for copper (partial waiver). The system must demonstrate that its distribution system and service lines and all drinking water supply plumbing, including plumbing conveying drinking water within all residences and buildings connected to the system, are free of lead-containing materials and/or copper-containing materials as those terms are defined as follows:
N.Y. Comp. Codes R. & Regs. Tit. 10 §§ 5-1.42