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Water: Water Quality Standards Academy

Basic Course: Supplemental Topics (NPDES Permit 10)

NPDES Permit Program

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Establishing WQBELs: A Four-Step Process

EPA has identified the following steps to assess the need for water quality-based effluent limits (WQBELs) and to then establish the limits as necessary based on the assessment:

Step 1.  Identify applicable water quality standards.
Step 2.  Characterize the effluent and receiving water.
Step 3.  Determine the need for parameter-specific WQBELs.
Step 4.  Calculate parameter-specific WQBELs.

Following these steps will enable States/Tribes to implement water quality standards in NPDES permits based on:

  • Knowing the current water quality standards, including any changes.
  • Being familiar with water quality standards implementation policies.
  • Using procedures adopted by the permitting authority to establish limitations that are as stringent as necessary to attain the State/Tribe’s water quality standards.

Key Point. The CWA requires effluent limits in NPDES permits that will ensure compliance with water quality standards. (CWA Section 301(b)(1)(C)) These limits are generally referred to as WQBELs.

This section of the module considers the four-step process in more detail.

For informational purposes only–Not official statements of EPA policy.

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