July 9, 2026
How to Negotiate NPDES Permit Limits
Lessons From 40 Years of Clean Water Act Practice
The Art of NPDES Permit Negotiation
National Pollutant Discharge Elimination System (NPDES) permit limits are not always set in stone. After four decades of writing and negotiating permits, one truth stands out: the data you bring to the table, and when you bring it, can significantly shape the outcome of the NPDES permitting process.
This blog explores how permit negotiation works, what drives the most complex permit limit discussions, and what two landmark cases reveal about the future of NPDES permitting. At GFT, our water quality team draws on regulatory experience to help clients navigate the full complexity of Clean Water Act (CWA) compliance.
What Is the NPDES Permit Program?
In 1972, Congress amended the Federal Water Pollution Control Act, more commonly referred to as the CWA. While technically a set of amendments, the changes represented a fundamental overhaul of the law. Among the most significant outcomes was the creation of the NPDES Permit Program, which has since become one of the most impactful regulatory programs in U.S. environmental law.
As its name suggests, the NPDES program’s goal is to eliminate pollutant discharges. This was consistent with Congress’ ambitious 1972 target of achieving zero discharge of pollutants by 1985 (CWA Section 101(a)(1)). Rather than mandating a specific technology, the program was designed to progressively tighten permit limits with the expectation that treatment technology would improve over time and ultimately achieve zero discharge.
Recognizing that this goal would take time, Congress also established interim milestones. One of the most well-known was the “fishable, swimmable” goal: achieving water quality that “provides for the protection and propagation of fish, shellfish, and wildlife and provides for recreation in and on the water” by July 1, 1983 (CWA Section 101(a)(2)). This goal continues to shape how states develop their water quality standards today.
How Are NPDES Permits Structured?
NPDES permits share a common structure. Each permit includes a cover page, a limits section, a monitoring and reporting section, special conditions, and standard conditions. Of these, the limits section and the monitoring and reporting section tend to draw the most attention from permittees, and for good reason. These are the sections that most directly drive resource requirements and, frequently, negotiation.
What Drives NPDES Permit Limit Negotiation?
The mix of technology-based and water-quality-based limit-setting creates a two-step process for permit writers that may sound straightforward but involves compiling and assessing a significant amount of data. The quantity and quality of the data provide the opportunity for discussion, negotiation, and creativity. The process for calculating technology-based effluent limitations (TBEL) tends to be more structured than the process for calculating water quality-based effluent limitations (WQBEL). This is because the TBELs are based on national standards, which have already undergone extensive negotiation. Calculating WQBELs is heavily based on site-specific conditions and data.
Step 1: Technology-Based Effluent Limitations
The permit writer first determines the category of discharge and the appropriate TBEL. For publicly owned treatment works (POTW), the municipal wastewater treatment plants that serve cities and towns, the CWA requires that limits be set based on secondary treatment standards. This applies uniformly, regardless of where the POTW’s discharge is located. For industrial discharges, the TBELs are set by effluent limitation guidelines for individual industrial categories. Like secondary treatment standards, these guidelines are applied uniformly across the country.
Step 2: Water Quality-Based Effluent Limitations
Next, the permit writer evaluates whether the TBEL is sufficiently protective of water quality standards in the receiving water body. CWA Section 301(b)(1)(C) requires that permits include any more stringent limitations necessary to meet those standards. The resulting WQBELs are site-specific and depend on the conditions of both the effluent and the receiving water.
As noted above, TBELs are calculated based on national standards that have undergone extensive regulatory development and negotiation. WQBELs, by contrast, are highly site-specific, focusing on local water quality, which is affected by many variables. The site-specific issues and number of variables also create considerably more room for negotiation. In addition to creating a basis for negotiation, these factors also create opportunities for collaboration. Permitting authorities and permit holders share the same goal, which is clean water, but often approach it with different perspectives and different responsibilities regarding how to achieve it. Permitting authorities have regulations that outline the permit development process and individual permit requirements, while permit holders are expected to comply with them. The opportunity for creativity lies in determining appropriate permit requirements.
There are many examples that highlight the differences in perspective between permitting authorities and permit holders, owing to the many variables to consider. The following two examples highlight very different sets of variables. The first involves the need for more comprehensive data, and the second for more reasonable expectations regarding regulatory requirements.
Case Study 1: Clean Water Services and Oregon’s Watershed-Based NPDES Permit
In 2004, Clean Water Services (CWS), a public water resources management utility in Oregon, was issued the nation’s first integrated, municipal watershed-based NPDES permit, which included Oregon’s first approved and implemented water quality trading program.
The initial driver for the creation of the watershed-based permit and trading program was a draft permit proposing very stringent temperature limits based on a water quality assessment and total maximum daily load (TMDL) for the river. Meeting those limits would have required CWS to install costly technology at its wastewater treatment plants (WWTP).
The permit was developed using a very traditional approach and assumptions for the effluent discharge and mixing with the river flow. CWS took a different approach. Rather than addressing the WWTP discharge in isolation, CWS proposed a watershed-based strategy that accounted for WWTP discharges, stormwater discharges, and nonpoint sources of pollutants, managing all of these through a combination of water quality trading and habitat restoration. The watershed analysis revealed a critical insight: the primary driver of elevated river temperatures was not the WWTP; it was solar radiation caused by the absence of riparian vegetation along the riverbank. Planting trees, it turned out, made more sense than installing chillers.
Traditional permitting approaches, which focus narrowly on point source effluent quality, can lead to the construction of costly treatment technologies that reduce relatively minor pollutant loads without meaningfully improving public health or water quality. The watershed approach, by contrast, directs resources toward the interventions with the greatest potential environmental impact, whether that means controlling stormwater, addressing WWTP discharges, or restoring riparian habitat.
CWS’s water quality trading program allowed the utility to earn regulatory credit toward compliance with temperature wasteload allocations (the share of a water body’s total allowable pollutant load assigned to a specific point source) by funding riparian restoration in the watershed. The results have been significant: trees planted along the river and its tributaries provide shade that moderates stream temperatures, improve habitat for fish and wildlife, and deliver broader ecological benefits that no wastewater treatment technology could replicate.
The CWS case is a compelling example of why combining watershed management with integrated planning produces better outcomes. When the full system is examined, it becomes clear that narrowly addressing WWTP effluent alone may not achieve the desired in-stream results. A more detailed description of this example can be found in: Cochran, Bobby, and Charles Logue. ‘A Watershed Approach to Improve Water Quality: Case Study of Clean Water Services’ Tualatin River Program.’ Journal of the American Water Resources Association (JAWRA) 47(1):29–38, 2011.
Case Study 2: San Francisco v. EPA and the End-Result Limits Ruling
On March 4, 2025, the U.S. Supreme Court issued a 5-4 decision in City and County of San Francisco v. Environmental Protection Agency (EPA), a case that addressed a long-standing and widespread problem in NPDES permitting: the use of “end-result” permit limits.
The case centered on the San Francisco Public Utilities Commission Oceanside Water Pollution Control Plant, which discharges into the Pacific Ocean. Because it is an ocean discharge, the facility’s NPDES permit is issued jointly under both state and federal jurisdiction. In its 2019 permit reissuance, EPA included two new provisions prohibiting the facility from causing or contributing to a violation of any applicable water quality standard (WQS, the numeric and narrative criteria set by states to protect designated uses of a water body) or creating a water quality nuisance.
The Court characterized these as “end-result” limits, provisions that hold permittees responsible for the overall condition of receiving waters, without specifying the measurable effluent limits needed to achieve that outcome. The Court held:
“…that §1311(b)(1)(C) does not authorize the EPA to include ‘end-result’ provisions in NPDES permits. Determining what steps a permittee must take to ensure that [WQS] are met is the EPA’s responsibility.”
In plain terms: the EPA must now set specific, measurable effluent limits in permits rather than holding permittees broadly accountable for the water quality of the receiving water body. Going forward, the EPA and state permitting agencies will need to impose direct, quantifiable restrictions in place of end-result conditions.
The San Francisco case highlights the importance of reading permits carefully and assessing the permit’s provisions regarding how compliance will be measured and achieved. Often, when permit provisions are unclear, they can be resolved through negotiation when they are identified early in the process. Unfortunately, there are times when litigation is needed. A more detailed assessment of this example can be found in: Bradley, P., and P. Calamita. ‘A Question of Authority: U.S. Supreme Court Reinforces the Need for Fair Notice and Due Process in Clean Water Act Permitting.’ Water Environment Technology, June 2025.
Key Takeaways for Permittees
The mix of technology-based and water-quality-based limit-setting creates a two-step process for permit writers that may sound straightforward but involves compiling and assessing a significant amount of data. The quantity and quality of the data provide the opportunity for discussion, negotiation, and creativity. The process for calculating technology-based effluent limitations (TBEL) tends to be more structured than the process for calculating water quality-based effluent limitations (WQBEL). This is because the TBELs are based on national standards, which have already undergone extensive negotiation. Calculating WQBELs is heavily based on site-specific conditions and data.
For permittees preparing for an upcoming permit renewal or facing challenging draft limits, three principles hold true:
- Engage early. Contact your permitting agency well in advance of permit reissuance. Early dialogue gives you the opportunity to share relevant data, raise concerns, and shape the permit before positions become fixed.
- Read the draft permit carefully. Submit substantive, data-supported comments on the draft permit. The comment period is one of the most underutilized tools available to permittees.
- Think beyond the discharge point. As the CWS case demonstrates, the most effective and cost-efficient solutions are often found by examining the entire system, not just the end of the pipe.
GFT’s water quality specialists apply deep NPDES permitting experience to complex permit negotiations, watershed-based planning, and Clean Water Act program management. If you’re navigating a permit renewal or facing emerging regulatory challenges, we’re here to help.
Meet our expert
Patrick Bradley
Senior Project Manager, Water
Pat Bradley has over 40 years of experience in National Pollutant Discharge Elimination System (NPDES) permit writing and negotiation, stormwater management, and Clean Water Act implementation.
Patrick Bradley
Senior Project Manager, Water
Pat Bradley has over 40 years of experience in National Pollutant Discharge Elimination System (NPDES) permit writing and negotiation, stormwater management, and Clean Water Act implementation.
Patrick Bradley
Senior Project Manager, Water
Pat Bradley has over 40 years of experience in National Pollutant Discharge Elimination System (NPDES) permit writing and negotiation, stormwater management, and Clean Water Act implementation.
Featured News & INSIGHTS
Searching for Water: Engineering Solutions for the Colorado River’s Survival
How Updated Data and Regional Detention Are Reducing Flood Risk in Texas
UPCOMING 10/22: Taking Back Control: Managing Cost and Risk Through Collaborative Delivery
UPCOMING 11/12: PFAS in 2026: From Detection to Decisions
Brown Receives 2026 George Warren Fuller Award From AWWA
In the News: WHCRWA Honors GFT’s Wayne Ahrens for 25 Years of Service
Abe Khademi, PEng
Amy Dziuk, PE, CFM
