QSD vs. QSP: Which Do You Need for Your SWPPP?

Here is the short answer: a QSD (Qualified SWPPP services Developer) prepares the SWPPP document, and a QSP (Qualified SWPPP Practitioner) implements it in the field during construction. Most projects over one acre of disturbance need both — and on smaller projects they can be the same person. Which credential you need depends on what role you are filling, not just whether your project requires a SWPPP at all.

If you are a developer, contractor, or project owner trying to figure out who to hire — or what your engineer needs to be certified as — this post breaks it down by threshold, role, and real project type so you can stop guessing.

What Is a SWPPP, and When Is One Required?

A Stormwater Pollution Prevention Plan (SWPPP) is a site-specific document required under the California Construction General Permit (CGP), Order 2009-0009-DWQ as amended by 2010-0014-DWQ and 2012-0006-DWQ, issued by the State Water Resources Control Board (SWRCB). The permit applies to construction sites that disturb one acre or more of land, or sites smaller than one acre that are part of a larger common plan of development that totals one acre or more.

The CGP classifies projects by risk level — Risk Level 1, 2, or 3 — based on factors like rainfall erosivity, proximity to receiving waters, and soil type. That risk level determines how detailed your SWPPP needs to be and what monitoring your QSP must perform. Risk Level 3 projects, for example, require a Rain Event Action Plan (REAP) and numeric action levels for turbidity and pH at discharge points.

Projects under one acre that are not part of a larger common plan are generally exempt from the CGP, though local municipal separate storm sewer system (MS4) permits may still require erosion and sediment control documentation. Always check with the local agency — a city like Oakland enforces its own stormwater ordinance under its Phase II MS4 permit, which can require BMPs even below the one-acre threshold.

What Does a QSD Actually Do?

The QSD is the person who writes and certifies the SWPPP. Under the CGP, the QSD must:

Prepare the SWPPP and all amendments
Develop the site map, erosion and sediment control BMP strategy, and good housekeeping measures
Conduct risk determination and assign the project risk level
Prepare the Rain Event Action Plan (REAP) for Risk Level 2 and 3 projects
Certify the SWPPP through the SWRCB’s Stormwater Multiple Application and Report Tracking System (SMARTS)

QSD certification is issued by the California Stormwater Quality Association (CASQA) in partnership with the SWRCB. To qualify, candidates must hold a qualifying professional credential — a California PE license, a California-licensed geologist, a Certified Engineering Geologist, or a Registered Environmental Assessor — and pass the QSD examination. A QSD without a PE license can still prepare a SWPPP, but plan sheets and grading documents require a licensed civil engineer.

What Does a QSP Actually Do?

The QSP is the person who manages the SWPPP on the ground during active construction. The QSP is responsible for:

Implementing, maintaining, and inspecting BMPs as specified in the SWPPP
Conducting pre-storm, storm event, and post-storm inspections
Completing visual monitoring and sampling (for Risk Level 2 and 3 projects)
Submitting inspection reports and annual certifications through SMARTS
Amending the SWPPP in coordination with the QSD when site conditions change

QSP certification has a broader eligibility base than QSD. Candidates need a qualifying credential — which includes, in addition to the professional licenses above, a Certified Inspector of Sediment and Erosion Control (CISEC) or other CASQA-recognized credentials — plus passing the QSP exam. This means a contractor’s field superintendent can become a QSP even without a PE license, making it feasible to keep implementation in-house.

Can One Person Hold Both Credentials?

Yes. A single individual can be both QSD and QSP, and on many mid-size projects that is exactly how it works. When your civil engineer holds both credentials, they prepare the SWPPP, certify it in SMARTS, and then oversee field implementation and inspections through construction. This is common on projects like K-12 school renovations, multifamily infill sites, and small commercial developments where the disturbed area is between one and five acres and the risk level is manageable.

On large, complex projects — think a 50-unit housing development with significant grading across multiple phases — it often makes more sense to have a dedicated QSP in the field and a QSD managing the permit compliance strategy separately. The CGP does not require them to be different people; it is a practical decision based on project size and construction pace.

What Are the Practical Thresholds and Edge Cases?

A few scenarios where the answer is not obvious:

Phased subdivisions: Under the Subdivision Map Act §66426, a tract map can be phased. If each phase individually disturbs less than one acre, but the overall project disturbs more, the CGP still applies to the common plan. You need a QSD and QSP for the whole project, not just the active phase.
Linear projects: Utility trenching and pipeline work that crosses multiple parcels and totals over one acre triggers CGP coverage, even if no single parcel segment reaches the threshold.
Redevelopment sites: Demolition of an existing structure followed by new construction counts toward disturbed acreage. Do not assume that building on a previously developed lot exempts you.
Emergency projects: The SWRCB does allow emergency permit coverage with abbreviated SWPPP requirements, but “emergency” has a specific regulatory definition — don’t assume a fast-tracked schedule qualifies.

A Practical Example: 10-Unit Condo on a 0.8-Acre Site in Oakland

Your project is a 10-unit condominium on a 0.8-acre infill lot in Oakland. The grading plan shows 0.8 acres of disturbance. You are not part of a larger common plan of development. In this case, the CGP does not apply — you are below the one-acre threshold and there is no larger plan to aggregate into.

However, Oakland’s MS4 permit and municipal code still require you to control erosion and prevent sediment from leaving the site. The City will likely require a Stormwater Control Plan and erosion/sediment control notes on your grading plan, prepared and stamped by a licensed civil engineer. You do not technically need a QSD-certified preparer for that document, but having one means the plan will be built around the same BMP framework your contractor already knows, and it will hold up if the Regional Water Quality Control Board ever reviews your project.

Now shift that same project to 1.1 acres. CGP coverage is required. You need a QSD to prepare and certify the SWPPP in SMARTS before ground disturbance, and a QSP on-site throughout construction. Risk level will likely be 1 or 2 depending on proximity to receiving waters and rainfall erosivity for the Oakland Hills versus flatlands location.

How Do QSD/QSP Requirements Interact With Other Permits?

The CGP does not operate in a vacuum. Your SWPPP strategy should be coordinated with: