EPA is promulgating the Unregulated Contaminant Monitoring Regulation (UCMR) for Public Water Systems (PWSs), which revises substantially the existing regulations for unregulated contaminant monitoring. This final rule includes a list of contaminants to be monitored, procedures for selecting a representative nationwide sample of small PWSs that will be required to monitor, the frequency and schedule for monitoring, the sampling points, the approved analytical methods to be used, and procedures for entering the monitoring data in the National Drinking Water Contaminant Occurrence Database (NCOD), as required under section 1445 of SDWA, as amended. The data in the database will be used to identify contaminants on the Drinking Water Contaminant Candidate List (CCL), to support the Administrator's determination of whether or not to develop drinking water standards for a particular contaminant, and to develop standards for the contaminants that the Administrator selects.

"EPA/815-Z-99-004." "Federal Register/Vol. 64, No. 180/Friday, September 17, 1999." "40 CFR Parts 9, 141 and 142." "FRL-6433-1." "RIN 2040-AD15."