# Revisions to the Unregulated Contaminant Monitoring Regulation (UCMR 3) for Public Water Systems
**Correction**
In rule document 2012-9978 appearing on pages 26072-26101 in the issue of Wednesday, May 2, 2012, make the following correction:
On pages 26072-26073, the table entitled
“EXHIBIT 1—APPLICABILITY OF UCMR 3 TO WATER UTILITIES BY SYSTEM TYPE AND SIZE” should read as set forth below:
| | | |
| --- | --- | --- |
| | | |
| System type | System size | |
| | Serving >10,000 | Serving ≤10,000 |
| CWS & NTNCWS | Requires all systems to monitor for List 1 chemicals | Requires 800 randomly selected systems to monitor for List 1 chemicals. EPA will pay for the analysis of samples. |
| TNCWS | No requirements | No requirements. |
| | | |
| System Type | System size | |
| | Serving >10,000 | Serving ≤10,000 |
| CWS & NTNCWS | Requires all systems serving more than 100,000, and 320 randomly selected systems serving 10,001 to 100,000 to monitor for List 2 chemicals | Requires 480 randomly selected systems to monitor for List 2 chemicals. EPA will pay for the analysis of samples. |
| TNCWS | No requirements | No requirements. |
| | | |
| System type | System size | |
| | Serving >1,000 | Serving ≤1,000 |
| CWS, TNCWS & NTNCWS | No requirements | Requires 800 randomly selected systems to permit EPA to sample and analyze List 3 microbes. The selected systems will be served by non-disinfecting ground water wells in vulnerable areas. EPA will pay for the analysis of samples. |