CDPHE Site Application vs. Discharge Permit Application: The Two-Step Process Colorado Developers Often Confuse Into One

Quick Answer

Colorado wastewater projects, particularly private treatment plants serving developments outside immediate municipal sewer service, often require more than one distinct approval step from the Colorado Department of Public Health and Environment, commonly referred to as CDPHE. A site application generally focuses on whether the proposed location, design basis, service area, and treatment concept are appropriate for the site and its surrounding conditions. A discharge permit application, evaluated separately, focuses on the actual legal authorization to discharge treated effluent along with the specific limits, monitoring requirements, and reporting obligations that follow. Developers who treat these as one combined approval, expecting a single review process to resolve both site feasibility and discharge authorization simultaneously, often run into schedule problems, missing information requests, redesign, and delayed review that a clearer understanding of the two-step sequence would have avoided.

Why Colorado Wastewater Approval Often Involves More Than One Step

A wastewater treatment facility raises two related but genuinely distinct questions. First, is this location, with this proposed treatment concept and this anticipated service area, actually a reasonable and appropriate place to put a treatment facility, considering site conditions, disposal or discharge method, and surrounding constraints. Second, assuming the site and concept are appropriate, what specific legal authorization, limits, and ongoing compliance conditions will actually govern the facility once it’s built and operating. These are different evaluations requiring different information, and treating them as a single combined question, rather than as sequential steps each requiring its own focused review, is where much of the confusion and resulting delay in this process tends to originate.

What a Site Application Focuses On

A site application generally addresses the fundamental feasibility question: does this specific site, given its location, surrounding land use, topography, and other physical characteristics, appropriately support the proposed wastewater treatment works. This includes evaluating the proposed treatment concept and design basis at a level sufficient to confirm the general approach is sound, understanding the anticipated service area and the flows it will generate, and confirming the proposed receiving water or disposal method, whether a stream discharge, land application, or another approach, is a reasonable fit for the site’s actual conditions. A site application is fundamentally about establishing that the proposed facility belongs where the developer wants to put it, before the more detailed work of establishing specific discharge limits and compliance conditions begins.

What a Discharge Permit Application Focuses On

A discharge permit application, evaluated as its own distinct step, focuses on the actual legal authorization for the facility to discharge treated effluent, and it establishes the specific limits, monitoring requirements, reporting obligations, and other compliance conditions that will govern the facility’s ongoing operation once approved. This step requires a more detailed technical and regulatory analysis than the site application, since it’s establishing the actual enforceable terms the facility will need to meet, rather than confirming general feasibility at the site level. A discharge permit application generally depends on the site-level questions already being resolved, since the specific limits and conditions that make sense for a facility depend on where it’s located, what it’s discharging to, and what treatment concept it’s using, all information the site application step is meant to establish first.

The Common Developer Mistake: Treating This as One Combined Approval

A developer who assumes site feasibility and discharge authorization will be evaluated together, in a single combined process, risks submitting an application that’s incomplete for whichever step is actually being reviewed, since the specific information needed to support a site feasibility determination differs from the information needed to support specific discharge limits and permit conditions. This mismatch commonly leads to information requests partway through review, project delays while missing information is prepared and submitted, and in some cases, a realization partway through the process that a design decision made without waiting for site level feedback needs to be revisited, requiring redesign before the discharge permit application can proceed on solid footing.

Schedule Problems From Combining the Two Steps

Developers planning a project timeline around a single combined wastewater approval process, rather than the actual sequential nature of site application followed by discharge permit application, often build an unrealistic assumption into their overall project schedule about when construction can actually begin. Understanding that these are genuinely sequential steps, with the discharge permit application generally depending on site level questions being resolved first, allows a more realistic project timeline that accounts for this sequence rather than assuming both approvals will move forward and conclude on the same timeline as a single unified process.

Package Plant Siting and the Site Application Step

For a private package treatment plant, siting decisions, exactly where on the property the facility will be located, how it relates to the proposed service area, and what disposal or discharge approach it will use, are central to the site application step specifically. Working through these siting questions with clear engineering justification before submitting a site application, rather than proposing a location chosen primarily for construction convenience without regard for how well it actually supports the proposed treatment and disposal approach, produces a stronger, more defensible site application likely to move through review with fewer follow-up questions.

Phased Development Flows

For a project developing in phases, the site application step needs to address anticipated flows across the development’s full intended build out, not just an initial phase, since the site’s fundamental appropriateness for the proposed treatment works depends on understanding what the facility will eventually need to handle, not only what it needs to handle on day one. A site application that only addresses initial phase flows risks needing revisiting as later phases come online, an outcome better avoided by addressing full anticipated build-out flows during the initial site-level evaluation.

Treatment Technology Selection

The specific treatment technology proposed for a facility is relevant to both the site application, at the level of confirming the general treatment concept is sound and appropriate for the site, and to the discharge permit application, at the level of establishing what specific effluent quality and corresponding limits the technology can reasonably be expected to achieve. Confirming treatment technology selection early, and ensuring it’s presented clearly and consistently across both application steps, helps keep the two steps aligned rather than risking a mismatch where a technology decision made after the site application was already submitted creates a inconsistency that needs to be resolved during discharge permit review.

Outfall Planning and Land Application Options

Whether a facility proposes a direct discharge to a receiving stream, requiring outfall planning similar in concept to the civil design considerations relevant to any surface water discharge, or a land application approach avoiding a direct stream discharge, this choice is fundamentally a site-level question that should be addressed and reasonably settled during the site application step, since it affects which specific discharge permit pathway and requirements will apply during the subsequent discharge permit application. Deferring this decision until the discharge permit application step, after the site application has already been submitted based on an unresolved or different assumption, creates exactly the kind of misalignment between the two steps this article is meant to help developers avoid.

Receiving Stream Constraints

Where a direct discharge to a receiving stream is proposed, that stream’s specific characteristics and any applicable water quality constraints are relevant to both the site application, at the level of confirming the receiving water can reasonably support a discharge at all, and the discharge permit application, at the level of establishing the specific limits that discharge will need to meet. Evaluating receiving stream constraints early, during site level planning, rather than discovering a significant constraint only once detailed discharge permit application work is already underway, helps avoid a late stage surprise that could affect the entire proposed treatment and discharge approach.

Engineering Reports and Application Materials

Each step in this process generally requires its own supporting engineering documentation, tailored to the specific questions that step is meant to address, and preparing thorough, well organized materials specifically suited to each step, rather than assuming materials prepared for one step will adequately serve the other, produces a stronger application and reduces the likelihood of a follow up information request slowing down review. Confirming exactly what supporting documentation each specific step requires, directly with CDPHE for the project at hand, is a necessary part of preparing a complete, review-ready application for either step.

Public Agency Coordination

Depending on a project’s specific location and circumstances, coordination with other public agencies beyond CDPHE, a local municipality, a special district, or another relevant authority, may factor into either the site application or discharge permit application process, or both. Identifying which other agencies are relevant to a specific project and coordinating with them proactively, rather than treating this coordination as a detail to handle only if it becomes necessary later, helps keep a project’s overall approval timeline realistic and reduces the risk of an unanticipated coordination requirement surfacing late in the process.

Timing Between Planning, Design, Permitting, and Construction

Because the site application and discharge permit application are sequential steps, each with its own review timeline, a realistic overall project schedule needs to account for this sequence explicitly, planning meaningful time for the site application to be reviewed and resolved before the discharge permit application is submitted, rather than assuming both will be prepared and submitted simultaneously and resolved on the same timeline. Developers who build this realistic sequential timeline into their overall project planning, and who coordinate engineering design work to align with this sequence rather than racing ahead of it, are considerably less likely to encounter the schedule problems this article describes.

Frequently Asked Questions

Can the site application and discharge permit application be submitted at the same time?

This depends on the specific project and CDPHE’s current procedural requirements, and should be confirmed directly with CDPHE rather than assumed, since even where some overlap in timing may be possible, the two steps generally still require their own distinct information and evaluation regardless of how their submission timing is coordinated.

What happens if we submit a discharge permit application before our site application is resolved?

This risks the kind of misalignment and follow up information requests discussed throughout this article, since discharge permit review generally depends on site level questions, siting, disposal method, treatment concept, already being settled, and submitting out of this sequence can create delay rather than saving time.

Does a phased development need a new site application for each phase?

This depends on how the original site application addressed anticipated build out, and should be confirmed with CDPHE and evaluated by an engineer familiar with the specific project, since an application that adequately addressed full anticipated build out from the start may not require a separate site application for each subsequent phase, while one that didn’t may need revisiting as phases progress.

Should we hire an engineer before starting either application?

Yes, engaging a qualified engineer early, before preparing either application, helps ensure siting, treatment concept, and discharge or disposal approach are all evaluated together and presented consistently across both steps, reducing the risk of the misalignment problems described throughout this article.

Related Resources

• Decentralized Wastewater Clusters: Designing Multiple Small Package Plants Across a Phased Development
• Package Plant Operator Staffing Requirements: What TCEQ Certification Level Does a Development Actually Need?
• Emergency Bypass and Backup Power Requirements for Package Plants: What TCEQ Requires for Reliability During Outages
• Outfall Design and Diffuser Engineering: The Overlooked Civil Design Work Behind a Compliant Discharge Point

Planning a Colorado Wastewater Project and Need Help Sequencing Site and Discharge Approvals?

MES helps Colorado developers understand the sequence of CDPHE approvals, prepare complete application materials, coordinate engineering design with permitting strategy, and reduce review delays before a project depends on wastewater approval.

We specialize in:

• Site feasibility evaluation for package plants, rural subdivisions, resort projects, and mixed use developments
• Treatment technology and disposal method selection aligned across site and discharge permit steps
• Engineering report preparation tailored to the specific requirements of each CDPHE application step
• Phased development flow projections that support long term site application adequacy
• Receiving stream and outfall evaluation for proposed direct discharge approaches
• Realistic project scheduling that accounts for the sequential nature of Colorado wastewater approvals

Modern Engineering Solutions, McKinney, Texas. Contact: (214) 833-6748 or mod-eng.com