I realize there's some irony in a stormwater consultant writing an article about how to choose a stormwater consultant. But after over a decade on the Front Range, I've been brought in to fix enough problems created by the wrong consultant that I think this is worth addressing honestly.
Not all stormwater consultants are the same. Some have deep expertise in your specific type of project and jurisdiction. Some are generalists who list stormwater as one of twenty services on their website. Some are great engineers with no construction experience. Some are great inspectors who couldn't design a detention facility if their career depended on it.
Choosing the right one for your project comes down to asking the right questions. Here are the five that matter most.
1. Have You Worked in This Jurisdiction Before?
This is the single most important question you can ask, and it's the one most people skip. Stormwater requirements in Colorado are layered. You've got the state CDPS permit (COR400000) setting the baseline, and then every MS4 jurisdiction adds its own standards on top. Denver's requirements are different from Aurora's. Douglas County is different from Lakewood. The Cherry Creek Basin has its own overlay through Regulation 72.
A consultant who has worked in your specific jurisdiction knows the local reviewers, understands their interpretation of the criteria, and can anticipate the comments you'll get during plan review. A consultant who hasn't will submit a plan that meets the state requirements and gets kicked back by the municipality for missing local details. That costs you time and money.
This isn't about having a personal relationship with the reviewer (though that doesn't hurt). It's about understanding that one municipality might require a pre-construction meeting before you mobilize, while another is fine with a plan submission and a phone call. It's about knowing that a specific jurisdiction requires inlet protection details from the MHFD USDCM Volume 3 rather than generic manufacturer specifications. It's the kind of knowledge that only comes from doing the work in that jurisdiction repeatedly.
If the consultant says “I've worked all over Colorado” but can't name a specific project in your city or county, that's a data point worth noting.
2. Will This Plan Be Site-Specific?
Every legitimate stormwater consultant starts with some kind of template or standard framework. That's fine and expected. The question is whether the deliverable will be customized to your actual site conditions or whether you're paying full price for a template with your project name pasted in.
A site-specific SWMP or SWPPP should reflect your actual topography, your actual drainage patterns, your actual soil conditions, your actual construction sequence, and the specific control measures appropriate for your site. The plan should show where water actually flows on your property, not where it flows on a generic site map. The control measures should be sized and located based on your contributing drainage areas, not copied from a standard detail sheet.
Ask to see a sample plan from a comparable project (with the client's permission, of course). Look for site-specific calculations, photographs of existing conditions, a phasing plan that reflects how the project will actually be built, and control measure details that reference specific locations on the site map. If everything looks generic and interchangeable, that's what you're buying.
3. Do You Provide Both Plan Preparation and Inspection Services?
This isn't a strict requirement, but there's genuine value in having the same consultant who prepared the SWMP also perform the ongoing inspections. The person who designed the control measure layout understands the intent behind every placement. They know why the sediment basin was located where it is, what drainage area it's capturing, and how it's supposed to perform. That context makes their inspections more insightful and their recommendations more practical.
It also creates a single point of accountability. If a control measure fails, you're not caught between the plan preparer saying “it was installed wrong” and the inspector saying “it was designed wrong.” One firm owns the whole process.
If the consultant only prepares plans, ask who they recommend for inspections. If they only do inspections, ask whether they can evaluate the quality of your existing SWMP or whether you need a separate review. The worst scenario is hiring a plan preparer who disappears after delivering the document and an inspector who's never seen the plan until their first site visit.
4. What Happens When Things Change?
Construction sites are dynamic. Phases shift. Grading plans get modified. The contractor decides to access the site from the east side instead of the west. A utility conflict moves the storm sewer alignment. An unexpected spring emerges in the middle of your excavation.
Every one of these changes can affect your stormwater management plan. The question is how your consultant handles it.
Ask about their process for plan revisions. Is there a set number of revisions included in the original scope? Are changes billed hourly? Is there a retainer option for projects that expect frequent modifications? How quickly can they turn around a revised plan when you need it for a municipal re-review?
The best consultants build flexibility into their scope and pricing because they know from experience that construction never goes exactly according to plan. The worst consultants deliver a plan on day one and charge you full price every time you need a change. Understand the arrangement before you sign.
5. Can You Explain the Permit Requirements in Plain English?
This one might sound odd, but it tells you a lot about whether the consultant is going to be a useful partner or just a document generator.
Stormwater compliance is full of jargon, permit references, and regulatory nuance. Your superintendent doesn't need to understand the difference between an EURV and a WQCV. What they need to understand is which areas of the site require protection, what needs to happen after a rain event, and what they should do if something fails. A good consultant translates the regulations into practical, job-site-level guidance.
Ask the consultant to explain what your CDPS permit requires. If they can lay it out clearly, in terms that a non-engineer would understand, without defaulting to acronyms and regulatory citations, they're likely going to be easy to work with and effective at communicating with your field team. If they can't explain it without reading from the permit, they might be technically competent but they're going to be difficult to work with when your superintendent calls with a question at 7 AM.
A Few Other Things Worth Considering
Certifications matter, but they're not everything. A PE (Professional Engineer) license means the consultant has met education, experience, and examination requirements and carries professional liability for their work. A CPESC (Certified Professional in Erosion and Sediment Control) demonstrates specific competence in stormwater and erosion control. A CESSWI (Certified Erosion, Sediment, and Stormwater Inspector) indicates training in field inspection. These credentials signal baseline competence, but they don't guarantee quality of work or fit for your project.
Size of firm doesn't determine quality. Some of the best stormwater work I've seen comes from solo practitioners and small firms that do nothing but stormwater. Some of the worst comes from large multi-disciplinary firms where stormwater is an afterthought handled by whoever has available hours. The right question isn't “how big is your firm” but “who specifically will be doing the work on my project, and what's their experience?”
Responsiveness is a feature. Construction doesn't wait for consultants to return emails. If you send a question on Tuesday morning and don't hear back until Friday, that's going to be a problem when your inspector finds a failed control measure before a rain event and you need guidance now. Ask about typical response times and communication preferences. The best working relationships I've had with clients are built on quick, practical communication, not formal reports delivered a week after the question was asked.
The Bottom Line
Choosing a stormwater consultant is like choosing any professional service provider: the cheapest option is rarely the best value, the most expensive option isn't automatically the best, and the right choice depends on what your specific project needs.
Ask these five questions, evaluate the answers honestly, and go with the consultant who demonstrates local knowledge, site-specific thinking, and the ability to communicate clearly. Everything else will follow from there.