Your 5-Point Pre-Construction Checklist for a More Resilient Stormwater Management System

Stormwater management is one of those things that looks straightforward on paper but can turn into a costly headache once the excavators arrive. A system that performs beautifully in a design model may fail in the field because of a single overlooked detail: a pipe slope that wasn't checked against actual grades, an inlet that gets buried during grading, or a detention basin that was built too shallow because the contractor misread the plans. The pre-construction phase is the last chance to catch these issues before they become expensive change orders or, worse, compliance violations. This guide offers a five-point checklist that we've found useful for teams who want to move from reactive fixes to proactive resilience. It's not a substitute for a full peer review, but it's a practical tool to bring to the pre-construction meeting and run through with your contractor, inspector, and design team.

1. Why a Pre-Construction Checklist Matters Now

Stormwater regulations have tightened significantly over the past decade. Many jurisdictions now require systems to manage not only the 10-year storm but also a 100-year event with an additional climate change factor. At the same time, construction schedules are often compressed, and material supply chains remain unpredictable. The result is that teams are under pressure to deliver complex systems faster, with less margin for error.

A pre-construction checklist is not just a bureaucratic step. It's a decision-making framework that surfaces hidden assumptions. For example, the design might assume that the subgrade soil has a certain infiltration rate, but if that rate was based on a single test pit dug during a dry season, it may not represent the conditions encountered during wet-season construction. Without a checklist that prompts you to verify soil conditions before mobilization, you could end up with a system that doesn't drain as intended.

Another reason this matters now is the growing use of low-impact development (LID) techniques like bioretention cells, permeable pavers, and green roofs. These systems are more sensitive to construction sequencing than conventional pipe-and-pond solutions. If the bioretention soil mix is compacted by heavy equipment before it's planted, its performance is permanently compromised. A checklist that includes a sequencing review can prevent that kind of damage.

We've seen projects where the design team and contractor had different interpretations of the same plan. The designer assumed the underdrain would be connected to a daylight outlet, while the contractor assumed it would tie into a storm sewer that didn't exist yet. A pre-construction checklist that includes a review of connection points and assumptions can resolve these mismatches before they become field problems.

Finally, there's the question of liability. When a system fails and a regulatory agency asks for documentation, having a signed-off checklist that shows you considered key risk factors can be invaluable. It demonstrates due diligence and can help protect your firm in disputes. So this isn't just about building better systems—it's about building defensible systems.

Who Should Use This Checklist

This checklist is intended for project engineers, construction managers, municipal plan reviewers, and general contractors who are responsible for stormwater compliance. It's designed to be reviewed collaboratively at the pre-construction conference, not handed out as a homework assignment. Each point should be discussed and documented, with action items assigned.

2. The Core Idea: Five Points That Cover the Most Common Failure Modes

After reviewing dozens of post-construction stormwater reports and talking with inspectors, we've identified five areas that account for the majority of field failures. These are not the only things that can go wrong, but they are the ones that are most often overlooked during pre-construction planning.

Point 1: Verify Site-Specific Infiltration Rates

Many designs rely on a single infiltration test result taken from a location that may not be representative of the entire site. During pre-construction, we recommend conducting at least three infiltration tests in the area where the infiltration system will be located, spaced to capture variability. If the system is large, consider additional tests. The tests should be performed at the actual depth of the proposed facility, not at the surface. We've seen cases where the surface soil had good infiltration but a shallow clay layer was present at the bottom of the excavation, rendering the system ineffective.

Point 2: Confirm Emergency Overflow Routing

Every detention or retention system needs a way to handle storms that exceed the design event. In the field, we've found that overflow weirs are sometimes built at the wrong elevation, or the overflow pipe is undersized because the contractor substituted a different pipe schedule. The pre-construction checklist should include a review of the overflow path from the basin to the receiving water body or storm sewer, and a confirmation that the overflow structure is clearly marked on the plans and accessible for inspection.

Point 3: Plan Sediment Control Sequencing

Sediment is the enemy of stormwater infrastructure. During construction, runoff carries soil into inlets, pipes, and basins, clogging them before the system is even operational. A common mistake is to install permanent stormwater structures too early, before the site is stabilized. The checklist should define the order of construction: temporary sediment basins first, then rough grading, then permanent structures, and finally stabilization. It should also specify who is responsible for cleaning out structures after major rain events during construction.

Point 4: Review Material Lead Times and Substitutions

We've seen projects where a proprietary treatment device was specified, but when the contractor went to order it, the lead time was 16 weeks—longer than the construction schedule. The team then had to scramble to find a substitute, which required a redesign and regulatory approval. The pre-construction checklist should include a review of all long-lead items and a discussion of acceptable substitutions. This is also the time to verify that the specified materials are actually available in the local market.

Point 5: Ensure Post-Construction Monitoring Access

Many systems require ongoing maintenance—cleaning of inlets, mowing of vegetated swales, replacement of filter media. But if the access roads or easements were not clearly defined in the construction documents, it can be difficult or impossible to perform this maintenance. The checklist should confirm that there is a legal and physical means to access all components of the system after the site is complete. This includes verifying that manholes are not paved over, that valve boxes are accessible, and that the maintenance plan is realistic given the site layout.

3. How the Checklist Works Under the Hood

The checklist is not a static document—it's a process. Each point should be discussed, documented, and assigned to a responsible party. Here's how we recommend using it in practice.

Step-by-Step Process

1. Pre-Meeting Preparation: The design team compiles the relevant information for each point (infiltration test results, overflow design details, sediment control plan, material list, and access plan). This is sent to the contractor and inspector at least one week before the pre-construction meeting.
2. Meeting Discussion: At the meeting, each point is reviewed in order. The team discusses potential conflicts, asks clarifying questions, and agrees on actions. For example, if the infiltration rate is lower than assumed, the team may decide to increase the size of the infiltration bed or add an underdrain.
3. Documentation: The outcomes are recorded on a checklist form. Each item is marked as "verified," "requires further action," or "not applicable." Action items are assigned a due date and a responsible person.
4. Follow-Up: Before construction begins, the project manager checks that all action items are resolved. If any item remains open, the start of construction is delayed until it's closed.

Why This Process Works

The checklist forces explicit communication at a point in the project where changes are still relatively cheap. Once the excavator is on site, every change costs time and money. By front-loading the verification, you reduce the likelihood of surprises. Additionally, the checklist creates a shared understanding among all parties. The contractor knows what the designer expects, the inspector knows what to look for, and the designer knows what the contractor is actually building.

Common Pitfalls

One pitfall is treating the checklist as a rubber-stamp exercise. We've seen teams go through each point and say "yes, that's fine" without actually checking the supporting data. To avoid this, require that each point be backed by a specific document or field observation. For example, for Point 1, the team should have the infiltration test reports in hand and compare the test location to the proposed facility location. For Point 4, the team should have written confirmation from suppliers that the specified materials can be delivered within the required timeframe.

4. Worked Example: A Medium-Density Residential Subdivision

Let's walk through a composite scenario that illustrates how the checklist might play out on a real project. This example is based on patterns we've observed across multiple projects, not a specific site.

Project Background

A 20-acre residential subdivision in the Mid-Atlantic region, with 60 single-family homes. The stormwater design includes a regional detention basin, two bioretention cells, and a series of grass swales. The design is based on a 10-year, 24-hour storm event with a 20% climate change factor. The soil report, based on two test pits, indicates a silt loam with an infiltration rate of 0.5 inches per hour.

Pre-Construction Meeting

At the pre-construction meeting, the team reviews the five points.

Point 1: Infiltration Rates. The contractor points out that the two test pits were dug in an area that will be the detention basin, but the bioretention cells are located in a different soil unit. The team decides to perform two additional infiltration tests at the bioretention locations. The results show a rate of 0.2 inches per hour, which is below the design assumption. The team decides to add an underdrain to the bioretention cells to ensure proper drainage.

Point 2: Emergency Overflow. The overflow weir for the detention basin is designed to discharge into a natural swale that leads to a stream. However, the contractor notes that the swale is currently blocked by a stockpile of topsoil. The team agrees to clear the swale before the basin is constructed and to install a temporary bypass if needed.

Point 3: Sediment Control Sequencing. The sediment control plan calls for a temporary silt fence around the entire site. But the contractor points out that the fence will need to be moved multiple times as grading progresses. The team revises the plan to use a combination of silt fence and a temporary sediment basin that can be converted into the permanent detention basin later. This reduces the number of fence relocations.

Point 4: Material Lead Times. The bioretention cells require a specific soil mix that includes sand, compost, and topsoil. The contractor calls his supplier and learns that the compost component is on backorder for six weeks. The team identifies an alternative supplier that can deliver within two weeks, and the designer confirms that the alternative mix meets the specifications. The change is documented.

Point 5: Access for Maintenance. The detention basin is located in a rear-yard easement that is only accessible through a narrow path between two houses. The contractor notes that this path is too narrow for a small backhoe, which would be needed to clean out the basin. The team decides to widen the path to 12 feet and record an access easement. This change is added to the construction documents.

Outcome

Because the team used the checklist, they identified and resolved five potential issues before construction began. The project was completed on schedule, and the stormwater system passed its first-year inspection with no problems. Without the checklist, the bioretention cells might have failed due to poor drainage, the overflow could have been blocked, and maintenance access would have been impossible.

5. Edge Cases and Exceptions

No checklist is perfect, and there are situations where the standard five points may need to be adapted. Here are some edge cases to consider.

High Groundwater Sites

On sites with shallow groundwater, infiltration may not be feasible. In these cases, Point 1 should be modified to focus on groundwater mounding analysis and the potential for exfiltration to cause basement flooding. The checklist should also include a review of dewatering plans during construction, as high groundwater can complicate excavation.

Retrofit Projects

When adding stormwater management to an existing development, the checklist needs to account for existing utilities, structures, and traffic. Point 5 (access) becomes especially critical because the system may be located in a constrained area. Additionally, Point 3 (sequencing) may need to include temporary traffic control and protection of existing landscaping.

Very Large Sites (>100 acres)

On large sites, the variability in soil conditions and topography can be significant. The checklist should include a requirement for a geotechnical baseline report that covers the entire site, not just a few test pits. Point 4 (materials) should also consider bulk material delivery logistics, as large volumes of stone or soil may require multiple deliveries and staging areas.

Green Infrastructure Only

For projects that rely entirely on green infrastructure (rain gardens, permeable pavement, etc.), the checklist should add a point about construction sequencing to prevent compaction. Many green infrastructure failures are caused by heavy equipment driving over the soil before it's planted. The checklist should specify that no construction traffic is allowed on areas designated for infiltration after the soil is prepared.

Regulatory Overlay

In some jurisdictions, the checklist items may overlap with regulatory requirements. For example, the National Pollutant Discharge Elimination System (NPDES) permit already requires a sediment control plan. In these cases, the checklist should be integrated with the permit requirements, not treated as a separate document. The pre-construction meeting can serve as a joint review of both the checklist and the permit conditions.

6. Limits of the Approach

While the five-point checklist covers many common failure modes, it is not a comprehensive quality assurance program. There are several limitations to be aware of.

It Does Not Replace Design Review

The checklist assumes that the design is already complete and correct. If the design itself has fundamental flaws—such as an undersized pipe or an incorrect watershed delineation—the checklist will not catch them. A separate design review, preferably by an independent engineer, should be conducted before the pre-construction meeting.

It Relies on Good Data

The checklist is only as good as the information fed into it. If the infiltration test results are inaccurate because the tests were performed incorrectly, the checklist will produce a false sense of security. Similarly, if the material lead times are based on optimistic vendor promises, the project may still face delays. The checklist should include a requirement that all data be verified by a qualified professional.

It Cannot Predict Extreme Events

Even with a thorough checklist, a stormwater system can be overwhelmed by an event that exceeds the design standard. The checklist can help ensure that the overflow works as intended, but it cannot prevent flooding from a 500-year storm. Teams should communicate this limitation to clients and regulators, and ensure that the system's design standard is clearly documented.

It Assumes a Collaborative Team

The checklist works best when all parties are willing to share information and work together. If the contractor is adversarial or the designer is unwilling to consider changes, the checklist becomes a box-checking exercise rather than a problem-solving tool. In such cases, the project manager may need to use the checklist as a contract document to enforce compliance.

It Does Not Cover Construction Phase Changes

Once construction begins, field conditions may change—a buried utility is discovered, a pipe breaks, or the owner requests a change. The checklist is a pre-construction tool; it does not address how to handle changes during construction. Teams should have a separate process for managing field changes, such as a request for information (RFI) or a change order procedure.

7. Reader FAQ

We've collected some common questions that come up when teams first adopt this checklist.

How long does a typical pre-construction meeting take with this checklist?

For a straightforward project, the meeting can be completed in 90 minutes to two hours. For complex projects with multiple sub-drainage areas, it may take half a day. The key is to prepare the data in advance so that the meeting is focused on discussion, not data gathering.

Who should attend the meeting?

At a minimum, the project engineer (or a senior design representative), the general contractor's project manager and superintendent, the civil inspector (if one is assigned), and the developer's representative. If the system includes proprietary components, the manufacturer's representative may also be invited for Point 4.

What if we find an issue that requires a redesign?

That's exactly the purpose of the checklist. If a redesign is needed, it should be done before construction starts. The team should agree on a timeline for the redesign and a budget for additional design fees. It's much cheaper to redesign on paper than to demolish and rebuild in the field.

Can we use this checklist for a project that is already under construction?

It's not ideal, but you can still use it as a gap analysis. Review each point and identify any that have not been addressed. For example, if you haven't verified the infiltration rate, you can still test it before the system is built. If you haven't confirmed overflow routing, you can check it before the final grading is done. The earlier you apply it, the more value you'll get.

Should the checklist be shared with the regulatory agency?

We recommend sharing it if the agency requests it, but it's not required. Some agencies appreciate the documentation because it shows proactive quality control. However, if the checklist reveals unresolved issues, you may want to resolve them before sharing. Consult with your legal team if you have concerns about liability.

What happens if a point is marked 'not applicable'?

That's fine, as long as the reason is documented. For example, if the project uses only conveyance (pipes and inlets) with no infiltration, then Point 1 is not applicable. But be careful: sometimes a point is marked 'not applicable' simply because the team didn't think about it. Require a brief justification for each 'not applicable' entry.

8. Practical Takeaways

We've covered the five points and how to apply them. Here are the concrete next steps to take after reading this guide.

Step 1: Download or Create a Checklist Template

Start with a simple table that lists the five points, with columns for status (verified, action needed, N/A), responsible party, due date, and notes. You can expand it later to include sub-points specific to your project. Keep it to one page if possible—a long checklist is less likely to be used.

Step 2: Customize It for Your Next Project

Before the pre-construction meeting, populate the checklist with the relevant data. For Point 1, attach the infiltration test report. For Point 4, attach the material list with lead times. The more specific you make it, the more useful it will be.

Step 3: Schedule the Pre-Construction Meeting Early

Don't wait until the week before construction starts. Schedule the meeting at least two weeks before mobilization, so there is time to resolve any issues that come up. Include the checklist as a standing agenda item.

Step 4: Document Everything

After the meeting, send out meeting minutes that include the completed checklist. Assign action items with clear deadlines. File the checklist with the project records—it could be useful for future reference or if a dispute arises.

Step 5: Review and Refine After Each Project

After construction is complete, review how the checklist performed. Did it catch everything? Were there any issues that it missed? Update the template based on lessons learned. Over time, you'll build a checklist that is tailored to your specific projects and local conditions.

Step 6: Share with Your Team

Encourage other project managers in your organization to use the checklist. The more it's used, the more feedback you'll get, and the better it will become. Consider making it a standard part of your company's quality management system.

Building a resilient stormwater system starts long before the first shovel hits the ground. The pre-construction phase is your last chance to catch errors, align expectations, and set the project up for success. Use the five-point checklist as a starting point, adapt it to your context, and make it a habit. Your future self—and the downstream environment—will thank you.