Frequent Questions

What are the different systems schedules and their population numbers?

There are four Initial Distribution System Evaluation (IDSE) compliance schedules. The four schedules are:

 

 If you are this kind of system:

 You are on IDSE schedule number:

 A system serving 100,000 or more people OR a system belonging to a combined distribution system in which the largest system serves 100,000 or more people

 1

 A system serving 50,000 to 99,999 people OR a system belonging to a combined distribution system in which the largest system serves 50,000 to 99,999 people

 2

 A system serving 10,000 to 49,999 people OR a system belonging to a combined distribution system in which the largest system serves 10,000 to 49,999 people

 3

 A community water system serving fewer than 10,000 people (and not belonging to a combined distribution system with a system serving greater than 10,000 people)

 4

 

For additional guidance on the Stage 2 Disinfectants and Disinfection Byproducts rule please visit http://water.epa.gov/lawsregs/rulesregs/sdwa/stage2/regulations.cfm.

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