The Environmental Protection Agency (EPA) has published the final Ground Water Rule, which is designed to reduce the risk of exposure to fecal contamination that may be present in public water systems that use ground water. The rule is expected to drive the use of membrane treatment systems and disinfection technologies as utilities work to achieve the required 4-log removal or inactivation of viruses.
The GWR applies to more than 147,000 public water systems that use groundwater. The rule also applies to any system that mixes surface and ground water if the ground water is added directly to the distribution system and provided to consumers without treatment equivalent to surface water treatment. In total, these systems provide drinking water to more than 100 million consumers.
The rule calls for periodic sanitary surveys of ground water systems, requiring the evaluation of eight critical elements and the identification of significant deficiencies. States must complete the initial survey by December 31, 2012, for most community water systems (CWSs) and by December 31, 2014, for CWSs with outstanding performance and for all non-community water systems.
On-going compliance monitoring is required to ensure that treatment technologies reliably achieve at least 99.99 percent (4-log) inactivation or removal of viruses.
Systems that don’t achieve 4-log removal or that have a positive coliform sample during testing will face increased monitoring requirements. To help identify high risk systems, states also have the option to require systems, at any time, to conduct source water assessment monitoring.
Any system with a significant deficiency or source water fecal contamination must either correct all significant deficiencies, eliminate the source of contamination, provide an alternate source of water, or provide treatment which reliably achieves 99.99 percent inactivation or removal of viruses.
The sanitary survey provisions in the rule build on existing state programs established under the 1989 Total Coliform Rule and the Interim Enhanced Surface Water Treatment Rule and give states the authority to define both outstanding performance and significant deficiencies.
The rule defines eight specific components that must be reviewed during a survey (to the extent that they apply to the individual water system being surveyed):
source;treatment;distribution system;finished water storage;pumps, pump facilities, and controls;monitoring, reporting, and data verification;system management and operation; andoperator compliance with state requirements.Cost of complying is expected to reach $62 million a year. Public water systems will bear the majority of costs. The annual household costs for community water systems (including those that do not add treatment) range from $0.21 to $16.54. Annual household costs for systems that undertake corrective actions range from $0.45 to $52.38, with 90 percent having household cost increases of no more than $3.20, according to EPA estimates.BackgroundThe GWR was designed to reduce public health risk from contaminated ground water, especially in high-risk or high-priority systems. EPA hopes the rule will reduce the average number of waterborne viral (rotovirus and echovirus) illnesses by nearly 42,000 illnesses each year from the current baseline estimate of approximately 185,000 (a 23 percent reduction in total illnesses). In addition, nonquantified benefits from the rule resulting in illness reduction from other viruses and bacteria are expected to be significant.The 1996 Amendments to the Safe Drinking Water Act required EPA to develop regulations that require disinfection of ground water systems “as necessary” to protect the public health (section 1412(b)(8)).Most cases of waterborne disease are characterized by gastrointestinal symptoms (e.g., diarrhea, vomiting, etc.) that are frequently self-limiting in healthy individuals and rarely require medical treatment. However, these same symptoms are much more serious and can be fatal for persons in sensitive subpopulations (such as young children, the elderly, and persons with compromised immune systems).Ground water that is susceptible to fecal contamination may contain harmful viruses or bacteria. Viral pathogens found in ground water systems may include enteric viruses such as Echovirus, Hepatitis A and E, Rotavirus and Noroviruses (i.e., Norwalk-like viruses) and enteric bacterial pathogens such as Escherichia coli (including E. coli O157:H7), Salmonella species, Shigella species, and Vibrio cholerae.Fecal contamination can reach ground water sources, including drinking water wells, from failed septic systems, leaking sewer lines, and by passing through the soil and large cracks in the ground. Fecal contamination from the surface may also get into a drinking water well along its casing or through cracks if the well is not properly constructed, protected, or maintained.