§141.712. Unfiltered system Cryptosporidium treatment requirements. — Inbound Citations

(b) The owner or operator of a community or non-community water system that is required to determine a bin classification under § 141.710, or to determine mean Cryptosporidium level under § 141.712, must notify persons served by the water system that the determination has not been made as required no later than 30 days after the system has failed report the determination as specified in § 141.710(e) or § 141.712(a), respectively. The notice must be repeated as specified in § 141.203(b). The notice is not required if the system is complying with a State-approved schedule to address the violation.

(3) Filtered systems must determine their Cryptosporidium treatment bin classification as described in § 141.710 and provide additional treatment for Cryptosporidium, if required, as described in § 141.711. All unfiltered systems must provide treatment for Cryptosporidium as described in § 141.712. Filtered and unfiltered systems must implement Cryptosporidium treatment according to the schedule in § 141.713.

(2) Unfiltered systems are not required to conduct source water monitoring under this subpart if the system will provide a total of at least 3-log Cryptosporidium inactivation, equivalent to meeting the treatment requirements for unfiltered systems with a mean Cryptosporidium concentration of greater than 0.01 oocysts/L in § 141.712.

(g) If the State determines that a previously collected data set submitted for grandfathering was generated during source water conditions that were not normal for the system, such as a drought, the State may disapprove the data. Alternatively, the State may approve the previously collected data if the system reports additional source water monitoring data, as determined by the State, to ensure that the data set used under § 141.710 or § 141.712 represents average source water conditions for the system.

(b) Following initial determination of the mean Cryptosporidium level under § 141.712(a)(1), unfiltered systems must provide the level of treatment for Cryptosporidium required under § 141.712 according to the schedule in paragraph (c) of this section.

(1) Systems receive the treatment credits listed in the table in paragraph (b) of this section by meeting the conditions for microbial toolbox options described in §§ 141.716 through 141.720. Systems apply these treatment credits to meet the treatment requirements in § 141.711 or § 141.712, as applicable.

(d) Unfiltered systems must report their mean source water Cryptosporidium level as described in § 141.712.

(v) The treatment processes or control measures that systems use to meet their Cryptosporidium treatment requirements under § 141.711 or § 141.712 of this chapter.

(b) The owner or operator of a community or non-community water system that is required to determine a bin classification under § 141.710, or to determine mean Cryptosporidium level under § 141.712, must notify persons served by the water system that the determination has not been made as required no later than 30 days after the system has failed report the determination as specified in § 141.710(e) or § 141.712(a), respectively. The notice must be repeated as specified in § 141.203(b). The notice is not required if the system is complying with a State-approved schedule to address the violation.

(iv) The determination of whether the mean Cryptosporidium level is greater than 0.01 oocysts/L after the initial and after the second round of source water monitoring for each unfiltered system, as described in § 141.712(a) of this chapter.

(iii) The determination of whether the mean Cryptosporidium level is greater than 0.01 oocysts/L both after the initial and after the second round of source water monitoring for each unfiltered system, as described in § 141.712(a) of this chapter.

(b) Following initial determination of the mean Cryptosporidium level under § 141.712(a)(1), unfiltered systems must provide the level of treatment for Cryptosporidium required under § 141.712 according to the schedule in paragraph (c) of this section.

(e) If the mean Cryptosporidium level for an unfiltered system changes following the second round of monitoring, as determined under § 141.712(a)(2), and if the system must provide a different level of Cryptosporidium treatment under § 141.712 due to this change, the system must meet this treatment requirement on a schedule the State approves.

(2) Systems may grandfather previously collected data where the sampling frequency within each month varied. If the Cryptosporidium sampling frequency varied, systems must follow the monthly averaging procedure in § 141.710(b)(5) or § 141.712(a)(3), as applicable, when calculating the bin classification for filtered systems or the mean Cryptosporidium concentration for unfiltered systems.