Sampling is conducted at the system’s entry point to the distribution system (EPDS).¹ The EPDS is the compliance sampling point anywhere on the finished water line that is representative of a water source. The EPDS tap must be located after the well or surface water intake, treatment, storage or pressure tank, and immediately prior to where the water is discharged into the distribution system, and before the first service connection.

So that sampling can be completed as scheduled, the water system owner/operator should ensure each EPDS:

• is in working order (when an EPDS is out of service, contact ADEQ to avoid missed monitoring violations and to help the monistoring assistance program (MAP) avoid unnecessary trips)
• has sampling taps installed
• has a sampling tag for proper identification (contact MAP sampler or MAP coordinator to obtain tags; MAP samplers can also assist in tagging)
• is easily accessible (if the EPDS is locked behind a security gate, make sure a water system representative is available with a key for sampling)
  
  

If MAP is unable to sample an EPDS, the water system must resolve the issue and contact MAP to re-schedule the sampling. Missed monitoring violations will be issued if sampling is not conducted.

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¹Arizona Administrative Code (A.A.C.) R18-4-206(D) | View >