United States Environmental Protection Agency Office of Water (4606) EPA816-F-01-011 May 2001 vwvw.epa.gov/safewater &EPA Interim Enhanced Surface Water Treatment Rule: A Quick Reference Guide Overview of the Rule Title Purpose General Description Utilities Covered Interim Enhanced Surface Water Treatment Rule (IESWTR) 63 FR 69478 - 69521, December 16, 1998, Vol. 63, No. 241 Revisions to the Interim Enhanced Surface Water Treatment Rule (IESWTR), the Stage 1 Disinfectants and Disinfection Byproducts Rule (Stage 1 DBPR), and Revisions to State Primacy Requirements to Implement the Safe Drinking Water Act (SDWA) Amendments 66 FR 3770, January 16, 2001, Vol 66, No. 29 Improve public health control of microbial contaminants, particularly Cryptosporidium. Prevent significant increases in microbial risk that might otherwise occur when systems implement the Stage 1 Disinfectants and Disinfection Byproducts Rule. Builds upon treatment technique approach and requirements of the 1989 Surface Water Treatment Rule. Relies on existing technologies currently in use at water treatment plants. Sanitary survey requirements apply to all public water systems using surface water or ground water under the direct influence of surface water, regardless of size. All remaining requirements apply to public water systems that use surface water or ground water under the direct influence of surface water and serve 10,000 or more people. Major Provisions Regulated Contaminants Cryptosporidium Turbidity Performance Standards > Maximum contaminant level goal (MCLG) of zero. * 99 percent (2 -log) physical removal for systems that filter. > Include in watershed control program for unfiltered systems. Conventional and direct filtration combined filter effluent: * < 0.3 nephelometric turbidity units (NTU) in at least 95 percent of measurements taken each month. » Maximum level of 1 NTU. Turbidity Monitoring Requirements (Conventional and Direct Filtration) Combined Filter Effluent Individual Filter Effluent * Performed every 4 hours to ensure compliance with turbidity performance standards. * Performed continuously (every 15 minutes) to assist treatment plant operators in understanding and assessing filter performance. Additional Requirements > Disinfection profiling and benchmarking. * Construction of new uncovered finished water storage facilities prohibited. * Sanitary surveys, conducted by the state, for all surface water and ground water under the direct influence of surface water systems regardless of size (every 3 years for community water systems and every 5 years for noncommunity water systems). ------- Profiling and Benchmarki For additional information on the IESWTR Call the Safe Drinking Water Hotline at 1-800-426-4791; visit the EPA web site at www.epa.gov/safewater; or contact your State drinking water representative. Additional material is available at www.epa.gov/ safewater/mdbp/ implement.html. Public water systems must evaluate impacts on microbial risk before changing disinfection practices to ensure adequate protection is maintained. The three major steps are: * Determine if a public water system needs to profile based on TTHM and HAAS levels (applicability monitoring) * Develop a disinfection profile that reflects daily Giardia lamblia inactivation for at least a year (systems using ozone or chloramines must also calculate inactivation of viruses) * Calculate a disinfection benchmark (lowest monthly inactivation) based on the profile and consult with the state prior to making a significant change to disinfection practices Critical Deadlines and Requirements For Drinking Water Systems February 16, 1999 March 1999 April 16, 1999 December 31, 1999 April 1,2000 March 31, 2001 January 1, 2002 Construction of uncovered finished water reservoirs is prohibited. Public water systems lacking ICR or other occurrence data begin 4 quarters of applicability monitoring for TTHM and HAAS to determine if disinfection profiling is necessary. Systems that have 4 consecutive quarters of HAAS occurrence data that meet the TTHM monitoring requirements must submit data to the state to determine if disinfection profiling is necessary. Public water systems with ICR data must submit it to states to determine if disinfection profiling is necessary. Public water systems must begin developing a disinfection profile if their annual average (based on 4 quarters of data) for TTHM is greater than or equal to 0.064 mg/L or HAAS is greater than or equal to 0.048 mg/L. Disinfection profile must be complete. Surface water systems or ground water under the direct influence of surface water systems serving 10,000 or more people must comply with all IESWTR provisions (e.g., turbidity standards, individual filter monitoring). For States December 16, 2000 January 2002 December 16, 2002 December 2004 December 2006 States submit IESWTR primacy revision applications to EPA (triggers interim primacy). States begin first round of sanitary surveys. Primacy extension deadline - all states with an extension must submit primacy revision applications to EPA. States must complete first round of sanitary surveys for community water systems. States must complete first round of sanitary surveys for noncommunity water systems. Public Health Benefits Implementation of the IESWTR will result in ... Estimated impacts of the IESWTR include ... Increased protection against gastrointestinal illnesses from Cryptosporidium and other pathogens through improvements in filtration. Reduced likelihood of endemic illness from Cryptosporidium by 110,000 to 463,000 cases annually. Reduced likelihood of outbreaks of cryptosporidiosis. National total annualized cost: $307 million 92 percent of households will incur an increase of less than $1 per month. Less than 1 percent of households will incur an increase of more than $5 per month (about $8 per month). ------- |