Water Regulations

USEPA

A US government agency responsible for implementing the Safe Drinking Water Act

C x T

A combination of the residual concentration of a disinfectant (mg/L) multiplied by the contact time (min), can be used as a measure of the disinfectant's effectiveness in killing or inactivating microorganisms.

Chlorite

A degradation product of chlorine dioxide and monitoring is required only for systems using chlorine dioxide as an oxidant or disinfectant. formation will increase over time so daily monitoring at the distribution system entry point and monthly samples are required.

Stage 1 DBPR (Disinfection By-products Rule)

Established an MCL of 0.080 mg/L for TTHM and 0.060 mg/L for HAA5 ("80/60" for 80 μg/L and 60 μg/L)

Ground Water Rule (GWR)

Established to reduce the risk of exposure to fecal contamination that may be present in PWSs that use groundwater sources

FBRR key components

1) recycle must reenter the treatment process prior to primary coagulant addition 2) direct filtration plants must report their recycle practices to the state and may need to treat their recycle streams 3) a self assesment must be done at those plants that use direct recycle and that operate fewer than 20 filters

Combined or Total Chlorine MRDL

4.0mg/L as Cl2

Filter Backwash Recycle Rule (FBRR)

Intended to help utilities minimize potential health risks associated with recycle, particularly associated with respect to Giardia and Crypto. Other contaminants of concern in the recycle stream include suspended solids (turb), dissolved metals (iron and manganese), and dissolved organic carbon.

Revised Total Coliform Rule (RTCR)

requires PWSs that are vulnerable to microbial contamination to identify and fix problems. Also established criteria for systems to qualify for and stay on reduced monitoring, thereby providing incentives for improved water system operation. Established an MCLG and an MCL for E. Coli (0mg/L) and eliminated the MCLG and MCL for total coliform

Unregulated Contaminant Monitoring Rule (UCMR)

the 1996 amendments to the SDWA require USEPA to establish criteria for a monitoring program for currently unregulated contaminants to generate data that USEPA can use to evaluate and prioritize contaminants that could potentially be regulated in the future.

Enhanced coagulation endpoint

the coagulant dosage and/or pH value that, when achieved, no longer produces significant TOC reduction

Haloacetic Acids (HAA5)

the sum of five specific haloacetic acids, which are mono-, di-, and trichloroacetic acids plus mono-, and dibromoacetic acids. cancer risks involve long periods of exposure

Total Trihalomethanes (TTHMs)

the sum of four trihalomethans, which are chloroform, bromodichloromethane, dibromochloromethane, and bromoform. cancer risks involve long periods of exposure.

Public Water System

A supply of piped water for human consumption that has at least 15 service connections, or serves 25 or more people 60 or more days/year.

Community PWS

A system whose customers are full time residents

Nontransient noncommunity PWS

An entity having its own water supply, serving an average of at least 25 people who do not live at the location but who use the water for more than 6 months per year. Must monitor only for nitrite, nitrate, and biological contamination.

Transient noncommunity PWS

An establishment having its own water system, where an average of at least 25 people per day visit and use the water occasionally or for only short periods of time. Must monitor only for nitrite, nitrate, and biological contamination.

Sanitary Survey

An onsite review of the water source, facilities, equipment, operation, and maintenance of the public water system for the purpose of evaluating the adequacy of such source, facilities, equipment, operation, and maintenance fo rproducing and distributing safe drinking water.

TTHM&HAA5 compliance value

Calculated number obtained by monitoring locations representative of the distribution system (systems serving >10,000 people who use surface water sources are required to monitor at least 4 locations per plant). Those systems with only one monitoring point must be representative of maximum residence time in the distrubtion system

Disinfection By-products (DBPs)

Chemical compounds formed by the reaction of disinfectants with organic compounds in water. At high concentrations, they are considered a danger to human health. Exposure of these needs to be evaluated on an average basis over time not a single incident.

Surface Water Treatment Rule (SWTR)

Goal of this regulation is to limit human exposure to harmful organisms, including cryptosporidium, by promoting achievement of particle and turbidity removal targets for surface water treatment systems. Combined filter effluent turb must be <0.3 ntu for 95% of samples collected each month. If in compliance, facilities have provided 2-log virus removal, 2.5-log Giardia removal and 2-log Cryptosporidium removal.

Bromate

MCL=0.010mg/L. Can be present in systems using ozone. Potentially formed during manufacture and storage of sodium hypochlorite.

Maximum Contaminant Level Goal (MCLG)

Nonenforceable health-based goals published along with the promulgation of an MCL. (originally called recommended maximum contaminant levels)

Lead and Copper Rule (LCR)

Objective is to control corrosiveness of the finished water in drinking water disribution systems to limit the amount of lead (Pb) and copper (Cu) that may be leached from certain metal pipes and fittings in the distribution system. Action level for Pb=0.015mg/L and Cu=1.3mg/L

Total Coliform Rule (TCR)

Objective is to promote routine surveillance of distribution system water quality to search for fecal matter and/or disease-causing bacteria.

Arsenic MCL

Reduced from 50μg/L to 10μg/L. Original SDWA required MCL to be set as close to the health goal (zero for arsenic and all other suspected carcinogens) as technically feasible.Amendments allowed USEPA the discretion to set the MCL above the technically feasible level.

LT2ESWTR

Supplements the SWTR requirements contained in the IESWTR for large surface water systems (>10,000 people). Uses cryptosporidium monitoring results to classify surface water sources into one of four USEPA-defined risk levels called "bins"

Maximum Residual Disinfectant Level (MRDL)

The highest level of a disinfectant allowed in drinking water without causing an unacceptable possibility of adverse health effects.

Maximum contaminant level (MCL)

The maximum permissible level of a contaminant in water as specified in the regulations of the Safe Drinking Water Act. The enforceable regulated level that is reasonably and economically achievable.

Stage 2 DBPR

Tightened requirements for DBPs. Makes compliance more challenging under the Stage 1 DBPR by changing the way compliance value is calculated and changing the compliance monitoring locations to sites representative of the greatest potential for THM and HAA formation. Compliance value under this rule is called the locational running annual average.

Enhanced Coagulation Requirements

Treatment plants must remove specific percentages of total organic carbon (TOC) based on their source water TOC and alkalinity levels. Unless they meet exemptions under the USEPA stage 1 DBPR Guidance, they must meet these requirements.

Running Annual Average

Used to determine the compliance value for TTHM and HAA5. Typically based on 4 monitoring locations sampled quarterly.

Public Notification Rule

includes requirements for reporting certain water quality monitoring violations and other water quality incidents, as well as requirements for the timing, distribution, and language of the public notices.