A. Suppliers of water for community public water systems shall collect and analyze one sample per plant at the entry point of the distribution system for the determination of sodium concentration. Samples shall be collected and analyzed annually for systems utilizing surface water sources in whole or in part, and at least every 3 years for systems utilizing solely ground water sources. The minimum number of samples required to be taken by the system shall be based on the number of treatment plants used by the system, except that multiple wells drawing raw water from a single aquifer may, at the Approving Authority's discretion, be considered one treatment plant for determining the minimum number of samples. The supplier of water may be required by the Approving Authority to collect and analyze water samples for sodium more frequently in locations where the sodium content is variable.
B. The supplier of water shall report to the Approving Authority the results of the analyses for sodium within the first 10 days of the month following the month in which the sample results were received or within the first 10 days following the end of the required monitoring period as stipulated by the Approving Authority, whichever of these is first. If greater than annual sampling is required, the supplier of water shall report the average sodium concentration within 10 days of the month following the month in which the analytical results of the last sample used for the annual average has been received.
C. The supplier of water shall notify appropriate local and State public health officials of the sodium levels by written notice by direct mail within 3 months. A copy of each notice required to be provided by this section shall be sent to the State within 10 days of its issuance. The supplier of water is not required to notify appropriate local and State public health officials of the sodium levels when the State provides the notices instead of the supplier.
D. Analysis for sodium shall be conducted as set forth in 40 CFR §141.23(k)(1).