4
There are various regulations that set turbidity standards for different types of public water systems, including 40 CFR 141.13, the 1989 Surface Water Treatment Rule, and the 1998 Interim Enhanced Surface Water Treatment Rule. The MCL for the monthly turbidity average is 1 NTU; the MCL for the 2-day average is 5 NTU for public water systems that are required to filter but have not yet installed filtration (40 CFR 141.13).
5 NTU--Nephelometric turbidity unit.
6
There are various regulations that set turbidity standards for different types of public water systems, including 40 CFR 141.13, the 1989 Surface Water Treatment Rule, and the 1998 Interim Enhanced Surface Water Treatment Rule. Systems subject to the Surface Water Treatment Rule (both filtered and unfiltered) may not exceed 5 NTU. In addition, in filtered systems, 95 percent of samples each month shall not exceed 0.5 NTU in public water systems using conventional or direct filtration and shall not exceed 1 NTU in public water systems using slow sand or diatomaceous earth filtration or other filtration technologies approved by the department.
7 TT--Treatment technique.
8
There are various regulations that set turbidity standards for different types of public water systems, including 40 CFR 141.13, the 1989 Surface Water Treatment Rule, and the 1998 Interim Enhanced Surface Water Treatment Rule. For public water systems subject to the interim enhanced surface water treatment rule (public water systems serving at least 10,000 people, using surface water or groundwater under the direct influence of surface water), that use conventional filtration or direct filtration, after January 1, 2002, the turbidity level of a public water system's combined filter effluent may not exceed 0.3 NTU in at least 95 percent of monthly measurements, and the turbidity level of a public water system's combined filter effluent shall not exceed 1 NTU at any time. Public water systems subject to the interim enhanced surface water treatment rule using technologies other than conventional, direct, slow sand, or diatomaceous earth filtration shall meet turbidity limits set by the department.
9 Surface water treatment rule and interim enhanced surface water treatment rule treatment technique violations that involve turbidity exceedances may use the health effects language for turbidity instead.
10 The bacteria detected by heterotrophic plate count are not necessarily harmful. HPC is simply an alternative method of determining disinfectant residual levels. The number of bacteria is an indicator of whether there is enough disinfectant in the distribution system.
11 Million fibers per liter.
12 Action Level = 0.015 mg/L.
13 Action Level = 1.3 mg/L.
14 Millirems per year.
15 Picocuries per liter.
16
Surface water systems and groundwater systems under the direct influence of surface water are regulated under Subpart H of 40 CFR part 141. Community and non-transient non-community systems using groundwater under the direct influence of surface water serving 10,000 or more shall comply with DBP MCLs and disinfectant maximum residual disinfectant levels beginning January 1, 2002. All other community and non-transient non-community systems shall meet the MCLs and MRDLs beginning January 1, 2004. Transient non-community systems using groundwater under the direct influence of surface water serving 10,000 or more persons and using chlorine dioxide as a disinfectant or oxidant shall comply with the chlorine dioxide MRDL beginning January 1, 2002. Transient non-community systems using groundwater under the direct influence of surface water serving fewer than 10,000 persons and public water systems using only groundwater not under the direct influence of surface water and using chlorine dioxide as a disinfectant or oxidant shall comply with the chlorine dioxide MRDL beginning January 1, 2004.
17 The MCL for total trihalomethanes is the sum of the concentrations of the individual trihalomethanes.
18 The MCL for haloacetic acids is the sum of the concentrations of the individual haloacetic acids.
19 MRDLG — Maximum residual disinfectant level goal.
20 MRDL — Maximum residual disinfectant level.
Appendix C to Subchapter VII
List of Acronyms Used in Public Notification Regulation
CCR Consumer Confidence Report
CWS Community Water System
DBP Disinfection Byproduct
EPA Environmental Protection Agency
HPC Heterotrophic Plate Count
IESWTR Interim Enhanced Surface Water Treatment Rule
IOC Inorganic Chemical
LCR Lead and Copper Rule
MCL Maximum Contaminant Level
MCLG Maximum Contaminant Level Goal
MRDL Maximum Residual Disinfectant Level
MRDLG Maximum Residual Disinfectant Level Goal
NCWS Non-Community Water System
NPDWR National Primary Drinking Water Regulation
NTNCWS Non-Transient Non-Community Water System
NTU Nephelometric Turbidity Unit
OGWDW Office of Groundwater and Drinking Water
OW Office of Water
PN Public Notification
PWS Public Water System
SDWA Safe Drinking Water Act
SMCL Secondary Maximum Contaminant Level
SOC Synthetic Organic Chemical
SWTR Surface Water Treatment Rule
TCR Total Coliform Rule
TT Treatment Technique
TWS Transient Non-Community Water System
VOC Volatile Organic Chemical
