In Upper Blackstone Water Pollution Abatement District v. U.S. Environmental Protection Agency, the U.S. Court of Appeals for the First Circuit upheld NPDES permit pollution limits for Massachusetts’s Blackstone River. The court deferred to the EPA’s permit limits under the Administrative Procedure Act’s arbitrary and capricious standard. Courts usually defer to an agency’s permit limits unless a court finds that the limits are outside a zone of reasonableness. States have an option of creating specific numeric water quality criteria for bodies of water within the state, vague narrative criteria, or both. This Comment argues that states should create numeric water quality criteria. Numeric criteria will communicate the state’s water quality goals more clearly to EPA permit writers. With the relevant information, permit writers will be able to create appropriate effluent limits in the first instance, which is important because courts rarely overturn the EPA’s permit limits.