A metal finishing prospect's environmental consultant will ask for your POTW's local limits schedule within the first week of due diligence. A food processor's engineer will want your surcharge rate structure and BOD baseline threshold before agreeing to a site visit. A chemical blender will need to know whether your plant has ever permitted a categorical industrial user under 40 CFR Part 403.
Most EDOs cannot answer any of these questions from existing materials. The information exists. Your pretreatment coordinator has it or can produce it. No one in the economic development office has asked for it in a format that functions as a prospect-facing document. The result is the same gap described in Issue #1 of The Playbook: the city has more infrastructure than it can prove, and the proof failure shows up as a screening elimination.
The POTW operates like any other infrastructure asset in the site data package. It has documentable capacity, numeric limits, and defined exclusions. The pretreatment coordinator is the counterparty who holds that data. The single most valuable output of the preparation work described here is a schedule of what the plant cannot accept, expressed in concentration limits and loading thresholds that sort compatible prospects from incompatible ones before either party burns pursuit resources.
Who Is in the Game
The sectors that generate process wastewater requiring POTW discharge and that are relevant to tier-3 and mid-sized city targeting: metal finishing and surface treatment, electroplating, food processing (dairy, meat, poultry, baked goods), beverage production, chemical blending and formulation, industrial laundry. If any of these appear in your sector-targeting strategy, your pretreatment coordinator is a counterparty you have not yet pre-cleared.
Two city profiles should stop here.
First: cities whose POTW has no remaining hydraulic headroom. If the plant is operating at or above 90% of design capacity with no funded expansion, you cannot absorb meaningful industrial process flow without a capital project that will outlast most prospect timelines.
Second: cities whose POTW is operating under a consent decree or administrative order for capacity or effluent violations. Under most consent decrees with capacity provisions, the POTW must demonstrate that new industrial connections will not cause or contribute to the violations that triggered the order. The coordinator may need to submit a loading analysis to the oversight authority before issuing a new SIU permit. Not a prohibition in principle. But the timeline and documentation burden makes the city uncompetitive for any deal where speed to operation matters.
Hydraulic headroom is in your POTW's monthly operating reports. Consent decrees and enforcement actions are searchable through EPA ECHO: search by facility name or NPDES permit number, open the Detailed Facility Report, and review compliance history and enforcement action sections. ECHO shows inspections over five years, noncompliance quarters over three years, and formal enforcement actions over five years. State environmental agency records may contain additional actions not yet reflected in ECHO.
The city that should keep reading: a POTW with 20–30% or more remaining hydraulic headroom, an approved pretreatment program, published local limits, and at least one current SIU permit on the books. That profile means the plant has capacity, the regulatory infrastructure to accept industrial discharge, and demonstrated experience managing the permit process.
The Federal Floor
40 CFR 403.5 establishes prohibitions that apply to every nondomestic discharger to every POTW in the country before local limits enter the picture. No coordinator can waive them. No local ordinance overrides them.
The prohibited categories: wastestreams with a closed-cup flashpoint below 140°F. Discharges with pH below 5.0, unless the POTW is specifically designed to accommodate them. Solid or viscous pollutants causing obstruction. Heat that would push plant influent above 104°F. Petroleum oil, nonbiodegradable cutting oil, or mineral-oil products in amounts causing interference or pass-through. Pollutants generating toxic gases, vapors, or fumes at levels creating acute worker health and safety problems.
These are universal refusal fields. Any prospect whose process generates wastestreams in these categories needs on-site pretreatment to bring the discharge below the prohibition threshold before it reaches the collection system. That pretreatment system is the prospect's capital cost. The EDO's role is to surface the prohibition in the site profile during initial evaluation, not during permit review.
Categorical Standards vs. Local Limits
Above the 403.5 floor, two separate regulatory structures govern what your POTW can accept. The distinction between them determines whether your pretreatment coordinator has any flexibility at all.
Categorical pretreatment standards are federal, technology-based limits for specific industrial categories codified in 40 CFR Parts 405–471. They apply as Pretreatment Standards for Existing Sources (PSES) and Pretreatment Standards for New Sources (PSNS). They are fixed. Your coordinator cannot waive them. They apply regardless of whether the POTW has an approved pretreatment program and regardless of whether the discharger has been issued a permit.
The two categories most relevant to tier-3 targeting are metal finishing (Part 433) and electroplating (Part 413). Both establish concentration-based PSES limits in mg/L for cadmium, chromium, copper, lead, nickel, silver, zinc, cyanide, and total toxic organics. Any facility performing electroplating, electroless plating, anodizing, coating, chemical etching and milling, or printed circuit board manufacture triggers categorical status the moment its process falls within the regulatory definition.
Local limits are where the coordinator has discretion. 40 CFR 403.5(c) requires POTWs with approved pretreatment programs to develop and enforce specific local limits derived from site-specific conditions: treatment technology, NPDES permit limits, receiving water quality, sludge disposal method. The limits come from a headworks loading analysis, which calculates total pollutant mass arriving at the plant's influent and allocates it across all industrial and nondomestic sources to prevent pass-through and interference. Local limits set the acceptance envelope: numeric thresholds for metals, BOD, TSS, FOG, pH, and other constituents from any industrial user.
The distinction matters for sector targeting because food processing, beverage production, and chemical blending generally do not trigger categorical pretreatment standards for indirect dischargers. Dairy products processing (Part 405) lists "No limitation" in its PSES sections and references only Part 403 general requirements. Meat and poultry products (Part 432) has PSES and PSNS reserved, not established, for key subparts. EPA withdrew a 2024 proposed rule on August 28, 2025 that would have established certain new pretreatment standards for the industry. Beverage production has no single EPA effluent guideline category; a brewery or bottling operation must be mapped by process and raw material to any relevant category or evaluated under Part 403, state rules, and local limits.
The beverage case is worth pausing on. A craft brewery or beverage bottling facility typically generates high-BOD, low-metals wastewater with pH variability from clean-in-place chemical cycles. No categorical standard governs the discharge. Whether the prospect works in your jurisdiction comes down to your local BOD surcharge threshold, your FOG limit, and your pH range. The pretreatment coordinator's numbers are the only numbers that matter.
A food or beverage prospect's discharge acceptability is governed primarily by local limits and Part 403 general requirements. The coordinator has real authority over whether that discharge works. A metal finishing prospect's discharge is governed by categorical standards the coordinator cannot change. Both need the local limits schedule, but for different reasons.
The Variance Is the Intelligence
Local limits vary dramatically between cities. The variance is the targeting data.
| Parameter | Pocatello, ID | Canton, OH | Albany, OR | Everett, WA |
|---|---|---|---|---|
| Copper | 0.515 mg/L daily max | 1.3067 mg/L | 3.4 mg/L | 5.91 lb/day (loading-based) |
| Oil & Grease / FOG | 350 mg/L (animal/vegetable) | 200 mg/L (total O&G) | — | — |
| pH range | 6.0–10.0 SU | 5.0–10.0 SU | 6.0–10.0 SU | 5.0–11.0 SU |
A metal finishing operation whose treated effluent runs 1.0 mg/L copper is viable in Canton, Albany, and potentially Everett. It fails in Pocatello without additional treatment. That single number eliminates or qualifies a sector target. Multiply it across cadmium, chromium, nickel, zinc, and the other regulated metals, and you have a compatibility matrix that tells you which wet-process industries can physically operate in your jurisdiction.
The same variance governs food processing viability through FOG thresholds. Pocatello allows 350 mg/L animal/vegetable oil and grease. Canton caps total oil and grease at 200 mg/L. A rendering operation or a large-scale fryer facility faces a fundamentally different pretreatment burden depending on which city it evaluates.
A chemical blending operation with alkaline wash cycles needs to know whether its discharge pH will require neutralization before it reaches the collection system. Canton's 5.0–10.0 SU range and Everett's 5.0–11.0 SU range accommodate different process chemistries than Pocatello's and Albany's 6.0–10.0 SU.
None of these numbers are secret. They are published in sewer use ordinances and on municipal websites. Most EDOs have never compiled them into a prospect-facing document.
SIU Triggers and Surcharge Economics
A prospect becomes a Significant Industrial User under 40 CFR 403.3 if it discharges an average of 25,000 gallons per day or more of process wastewater, contributes 5% or more of the POTW's average dry-weather hydraulic or organic capacity, or is designated by the control authority based on reasonable potential to affect operations. Any industrial user subject to categorical pretreatment standards is automatically an SIU. SIU designation triggers individual permit requirements under 40 CFR 403.8(f): effluent limits, self-monitoring and reporting, compliance schedules, slug-discharge controls.
Both thresholds are pre-clearable screening numbers. If your POTW's average dry-weather flow is 4 MGD, the 5% hydraulic trigger is 200,000 GPD. A food processing facility discharging 30,000 GPD of process wastewater clears the SIU volume trigger alone. A small craft brewery at 8,000 GPD will not, unless it triggers categorical status or the coordinator designates it. Knowing where the thresholds fall lets you tell a prospect immediately whether they face an individual discharge permit or a general control mechanism.
Surcharges are the other pre-clearable cost element. Most POTWs with industrial users assess surcharges for discharges exceeding residential-strength assumptions. The structure is consistent: a baseline threshold for BOD, TSS, and sometimes COD, FOG, ammonia, or phosphorus, with a per-pound charge for concentrations above the threshold.
| City | BOD Threshold | BOD Rate ($/lb above) | TSS Threshold | TSS Rate ($/lb above) |
|---|---|---|---|---|
| Austin, TX | 200 mg/L | $0.82 | 200 mg/L | $0.77 |
| Killeen, TX | 250 mg/L | $0.3825 | 300 mg/L | $0.240 |
A food processing facility discharging 50,000 GPD at 800 mg/L BOD faces a materially different annual surcharge bill depending on which city it evaluates. The prospect's engineer will run the cost model. The inputs need to be in the site data package.
The Pre-Clearable Inventory
The following can be compiled from the pretreatment coordinator into a single document before any prospect appears:
Remaining hydraulic headroom. Design capacity minus current average dry-weather flow, expressed in MGD. Include the five-year trend: increasing, stable, or declining.
Current local limits schedule. The full numeric table: every regulated parameter, the concentration or loading limit, and the effective date. If limits are under review or revision, note the expected timeline.
Surcharge rate schedule. Baseline thresholds and per-unit rates for every surcharged parameter. Current effective date and any scheduled rate adjustments.
SIU and categorical-user thresholds. The 25,000 GPD process-wastewater threshold, the 5% capacity threshold calculated for your specific plant, and a list of which EPA effluent guideline categories the POTW has experience permitting. If the plant currently has categorical industrial users, note the categories.
General pretreatment permit review timeline. Application to issued permit. Everett, Washington quotes three weeks for initial review and 90 days to final permit. Express it as a named sequence: application completeness review, discharge characterization evaluation, draft permit, public notice if required, final permit issuance.
Pretreatment program status. Does the POTW have an EPA- or state-approved pretreatment program? POTWs with design flow above 5 MGD that receive industrial pollutants subject to pretreatment standards are required to have one. Smaller POTWs may not. If no approved program exists, the state or EPA regional office is the control authority, and the permit path is different.
NPDES permit status and compliance history. Current permit expiration date, any compliance schedule or administrative order conditions that constrain new industrial loading, and the ECHO facility report URL so the prospect's environmental team can verify independently.
Title the compiled document "Industrial Discharge Profile" or equivalent. The pretreatment coordinator reviews and signs off on the final version with a date. Format it as a standalone PDF. It goes into the site data package alongside utility capacity letters and zoning confirmations, positioned so the prospect's environmental team can hand it to their consultant without calling your office. Every number in it is the coordinator's to defend.
What Requires a Named Prospect
Everything above can be compiled today. Everything below requires a specific discharge characterization from a specific facility.
The Everett, Washington discharge permit application illustrates the scope. It requires the applicant's process description, products manufactured, wastewater-generating processes with gallons per day by process, production rate, batch versus continuous discharge profile, materials and chemicals with potential to enter the sewer, pretreatment methods and equipment, a plant layout diagram showing all discharge points, and a pollutant inventory across metals, volatile compounds, semivolatile compounds, and other regulated constituents.
None of this can be answered generically. The EDO cannot complete it on the prospect's behalf. What the EDO can do is provide the blank application or checklist to the prospect's environmental team at first contact, alongside the pre-clearable inventory. The pre-clearable document answers whether the plant can handle this category of discharge. The application process determines whether the plant can handle this specific discharge at this specific volume. Crossing that boundary prematurely wastes the coordinator's time and produces answers that do not bind.
Refusal Fields as Targeting Intelligence
Most EDOs present POTW capacity as an asset. It is one. But the constraint profile sorts prospects faster than the capacity claim.
Compile the refusal fields. Map them against the sector targets in the economic development strategy.
If the local copper limit is 0.5 mg/L and the strategy targets metal finishing, the city is pursuing a sector whose typical treated effluent will not comply without significant additional on-site investment by the prospect. That is eight months of courtship ending in a due-diligence exit. If the BOD surcharge threshold is 200 mg/L and the strategy targets food processing, the pre-cleared prospect set narrows to operations with on-site equalization or inherently low-strength discharge: bakeries, dry-goods packaging, beverage bottling with CIP recovery. Not rendering. Not wet pet food manufacturing. Not large-scale dairy processing without pretreatment. And if the POTW has no experience permitting categorical users under Part 433, a metal finishing prospect's environmental team will flag the learning curve as a timeline risk regardless of local limits.
The pretreatment coordinator is the counterparty whose pre-clearance makes the deal defensible. The document described here is the proof artifact. Most cities served by a POTW with remaining headroom and published local limits can produce it in two meetings with the coordinator and a week of compilation.
- Utility infrastructure still dominates: The 2026 Site Selectors Guild/DCI Pulse Check reported utility and infrastructure capacity as the top site-elimination factor at 61%, reinforcing that wastewater documentation sits inside a broader infrastructure-proof problem.
- FERC's large-load orders expand: FERC's June 2026 action directed all six RTOs/ISOs to justify or reform rules governing how manufacturing facilities and other large energy users connect to the grid, a parallel to the pretreatment permit path for wet-process users.
- State site-readiness rounds are open: Alabama's SEEDS Round 4 is accepting applications through August 31 for approximately $11.7 million in site-assessment grants requiring at least 50 acres and documented site ownership, a funding path that could support wastewater infrastructure studies alongside other due diligence.
- Meat and poultry pretreatment standards withdrawn: EPA withdrew a 2024 proposed rule on August 28, 2025 that would have established new pretreatment standards for the meat and poultry products industry, leaving indirect dischargers in that sector governed by Part 403 general requirements and local limits rather than categorical standards.