How to Choose a Stormwater Consultant: Questions to Ask
Hiring the wrong stormwater consultant can cost you weeks of delays, permit rejections, and expensive redesigns. The right one accelerates your project, navigates agency relationships smoothly, and designs systems that are both compliant and constructible. Here’s what to evaluate before signing the contract.
What Credentials Do They Actually Hold?
Not all stormwater engineers are created equal:
PE license: Do they hold a Professional Engineer license in California? This is non-negotiable for responsible charge of stormwater plans. Ask to see the license and verify the expiration date.
Specialization: Are they a civil engineer with stormwater focus, or a general civil engineer who occasionally does stormwater? Stormwater is a distinct discipline. Prefer someone whose projects are consistently water/drainage-related.
Certifications: CEQA training, SWPPP (Storm Water Pollution Prevention Plan) QSP/QSD certification, Low Impact Development (LID) training, or LEED accreditation? These indicate deeper knowledge than a standard PE.
Continuing education: Do they attend conferences (BASMAA, ASCE, state RWQCB workshops)? Active participation in professional groups suggests they stay current on code changes and best practices.
Have They Worked in Your Jurisdiction?
Stormwater requirements vary significantly by county and city:
Alameda County: ACCWP standards, emphasis on infiltration where feasible. Oakland and Berkeley have local C.3 tweaks.
Marin County: Very infiltration-forward. Bioretention basins preferred over detention ponds.
San Francisco: SFPUC standards, stringent water-quality requirements, frequent green infrastructure mandates.
Santa Clara County (Santa Cruz Mountains): Nitrate-sensitive, often require advanced treatment or retention.
Ask for references in your specific jurisdiction. A consultant with 20 projects in Alameda County will navigate the local review culture faster than someone from San Diego.
How Many Projects Have They Permitted?
Experience matters. Ask:
How many C.3 projects have they completed from design through final sign-off?
Have they designed for projects of similar size and type to yours? (A 50-acre mixed-use project requires different expertise than a 2-acre parking lot.)
How many have gone through agency review without major comments or rework? A consultant who gets plans approved on first or second submission is worth the premium.
Prefer consultants with at least 50–100 completed stormwater designs. This isn’t a field where on-the-job training is acceptable.
Do They Have Strong Agency Relationships?
The best stormwater engineers have working relationships with local water boards, public works departments, and planning agencies:
Pre-design meetings: Do they routinely attend early coordination meetings with agencies? This prevents expensive mid-design pivots.
Known to reviewers: When an agency sees the consultant’s name on a submittal, do they groan (bad track record) or nod (trusted, responsive)? Ask your architect or contractor what the local reputation is.
Responsive to review comments: After agency feedback, do they respond promptly and incorporate feedback thoughtfully, or do they argue and delay?
Red Flags: What to Avoid
Watch out for these warning signs:
‘One-size-fits-all’ designs: A consultant who proposes the same BMP strategy for every project isn’t thinking. Stormwater design is site-specific (soil, infiltration, slope, utilities, etc.)
Unfamiliar with recent code changes: If they reference outdated versions of BASMAA guidelines or don’t know the difference between MRP and local C.3 provisions, move on.
No references: A consultant unwilling to provide project references is hiding something. Always call references and ask about rework, delays, and cost surprises.
Pressure to use their preferred BMP vendor: Some consultants have financial relationships with detention tank or separator manufacturers. That’s not necessarily disqualifying, but transparency is. Ask if they have preferred vendors and why.
Lowest bidder: Stormwater design isn’t a commodity. The cheapest bid often reflects inexperience, inadequate site investigation, or plans that will fail review. Budget 20–30% above the lowest quote for competence.
Interview Questions: Go Deeper
Beyond credentials, ask these scenario questions:
‘Walk me through your approach to site design on a 3-acre retail site in Alameda.’ Listen for mentions of: infiltration testing, site constraints, interaction with parking design, BMP sizing, and agency coordination.
‘Your client gets agency comments requesting infiltration testing. What’s your response?’ Good answer: ‘We conduct ASTM D3385 testing early in design to inform BMP sizing. If infiltration rate is low, we pivot to bioretention or proprietary treatment.’
‘How do you handle conflicts between stormwater BMPs and landscape design?’ Good answer: ‘Coordinate early with the landscape architect. Work together on tree trenches, bioswales, and planting palettes that serve both stormwater and aesthetics.’
‘Tell me about a project where stormwater requirements changed mid-design. How did you manage it?’ This reveals adaptability and communication skills.
Cost Expectations and Value
Stormwater design costs vary by project complexity:
Small commercial (2–5 acres, simple grading): $8K–15K
Mixed-use or complex site (10–20 acres, multiple BMPs): $25K–50K
Large master-planned development (50+ acres): $75K–150K+
These are professional fees. If someone quotes $2K for a 10-acre project, they’re either junior staff doing commodity work or your project is in serious trouble. A skilled stormwater engineer earning their fee will save you money on rework, delays, and post-construction compliance headaches.
Final Check: References and Verification
Before signing, call at least two references and ask:
Were there any surprises or rework in the agency review process? If yes, was it due to site conditions or the consultant’s oversight?
Did the design prove constructible? Were there issues during grading or construction related to stormwater infrastructure?
How responsive were they to changes or questions during design?
Would you hire them again?
Also verify their license with the Professional Engineers Board of California (PEBC) and check for any complaints or disciplinary actions.
Getting It Right
A good stormwater consultant accelerates your project, navigates agency relationships, and designs systems that work. A poor one delays you, creates friction with agencies, and designs systems that fail in the field. The difference in cost is minimal — the difference in outcomes is enormous.
Take 2–3 weeks to interview consultants properly. Ask references to calls. Verify credentials. The investment pays for itself many times over in faster permitting and avoided rework.
Not sure how to vet a stormwater consultant on your next project? We’ve worked alongside dozens of them. Let us help you identify the right partner. Contact Calichi Design Group.