The Environmental Protection Agency is proposing to require that states survey all drinking water systems. Ground water systems at risk of contamination would have to be monitored at the source and corrective action taken to deal with any contamination found. A final rule is expected to be announced in November.

Now only surface water systems and systems using ground water under the direct influence of surface water must disinfect water supplies. The 1996 amendments to the Safe Drinking Water Act require EPA to develop regulations that require disinfection of ground water systems "as necessary" to protect public health.

The proposed ground water rule will specify when corrective action, including disinfection, is required to protect consumers from bacteria and viruses when they receive water from ground water systems. The proposal calls for system sanitary surveys by the states and identification of significant deficiencies; hydrogeologic sensitivity assessments for undisinfected systems; source water microbial monitoring by systems that do not disinfect and draw from hydrogeologically sensitive aquifers or have detected fecal indicators within the system’s distribution system and corrective action by any system with significant deficiencies or positive microbial samples indicating fecal contamination.

For a copy of the proposed rule, click here.