Roof collection and final site drainage should be reviewed on one coordination drawing because they are a single water path, not two separate systems. Every gallon that leaves a downspout eventually crosses graded soil, a swale, a driveway, or a neighboring lot line, and if the roof plan and the site grading plan are drawn by different people at different times, the discharge point on paper often does not match a place on the ground that can actually carry water away without causing erosion or ponding.
This article explains why a combined roof-to-site coordination drawing is useful planning practice and summarizes what two public agencies, the City of Charlotte and York County, South Carolina, publish about stormwater review. It is not a substitute for a site-specific stormwater plan, a licensed engineer's grading design, or a determination from the authority having jurisdiction. Requirements change, and every property owner should confirm current submittal and review expectations directly with the applicable city or county stormwater office before design work advances.
What Current Public Sources Establish
The City of Charlotte publishes stormwater regulations covering how development and redevelopment projects manage runoff, including standards that apply to both public and private property within its jurisdiction. The published material addresses topics such as post-construction runoff controls and the general framework property owners and design teams work within when a project falls under the city's stormwater program.
York County, South Carolina maintains a separate stormwater plan review process for projects within county jurisdiction. Its published page describes the review function local government performs before certain site work proceeds, which is a reminder that stormwater review is a jurisdiction-specific process rather than a single statewide or regional standard.
Because Charlotte and York County are two different authorities with two different published programs, a project near the state line or within either jurisdiction should never assume one set of expectations applies to both. The specific submittal requirements, review triggers, and documentation each authority expects can differ, and both can change over time.
- Charlotte's stormwater regulations page addresses runoff management expectations within city jurisdiction.
- York County's stormwater plan review page describes the county's own review process for qualifying projects.
- Neither source should be treated as a universal statewide standard; jurisdiction determines which rules apply.
Inputs and Existing Conditions to Document
Before a coordination drawing can be useful, the project team needs an honest picture of what already exists on the lot. That means documenting existing grades, natural drainage patterns, any existing impervious area, the location of nearby storm structures or swales, and any easements or setbacks that limit where water can be directed.
On the building side, the roof plan needs to show every roof area, valley, and downspout location along with the general direction each downspout will discharge. On the site side, the grading plan needs to show finished contours, any planned swales or drainage structures, and the final discharge point where water leaves the property or enters an approved system.
- Existing topography and drainage patterns across the lot before any new construction.
- Location and capacity assumptions for every roof downspout or scupper.
- Planned finished grades, swales, and any drainage structures shown on the site plan.
- Property lines, easements, and adjacent property conditions that could be affected by discharge.
Step-by-Step Owner and Project-Team Review
A useful coordination review starts by placing the roof plan and the site grading plan side by side, or ideally overlaid on one drawing, so every downspout can be traced to a specific point on the finished grade. The team then follows that water visually from the roof edge to the ground, across the yard, and to wherever it is intended to leave the property or enter a stormwater feature.
This walk-through often reveals gaps that are hard to catch when the two plans are reviewed separately. A downspout might discharge onto a slope that has not been shown with enough detail, or a grading plan might assume a flow path that does not account for where the roof actually concentrates water. Catching these gaps on a drawing, before construction, is far more practical than discovering them after a storm.
For any property under Charlotte or York County jurisdiction, this internal coordination step does not replace whatever formal stormwater plan review that authority requires. It is a practical planning exercise that a project team can use to prepare a more complete and coordinated submission when a jurisdiction does require formal review.
- Overlay or align the roof plan and site grading plan on one working drawing.
- Trace each downspout's discharge point to a specific location on the finished grade.
- Confirm the flow path across the lot to the final discharge point or connection.
- Note any location where roof discharge and site grading do not clearly connect.
Responsibilities, Dependencies, and Hold Points
Coordinating roof and site drainage depends on clear roles. The architect or designer typically controls the roof plan and downspout layout. A civil designer, engineer, or site planner typically controls the grading plan and any drainage structures. The property owner is often the only party who sees both documents together unless someone on the project team is specifically tasked with that coordination review.
Because these two disciplines can be produced on different schedules, it helps to set a hold point, meaning a specific stage in design where the roof plan and site plan must be reviewed together before either moves forward to permitting or construction. Without that hold point, it is common for a roof design to be finalized before the site grading plan is complete, or the reverse, leaving no one responsible for confirming the two agree.
- Identify who controls the roof plan and who controls the site grading plan.
- Set a specific project stage where both plans are reviewed together before proceeding.
- Confirm who is responsible for updating either plan if a conflict is found.
- Keep the coordination drawing available for reference through construction, not just design.
Common Coordination Failures
Some of the most frequent problems are not dramatic engineering errors but simple gaps between documents drawn separately. A downspout may be shown discharging directly onto a neighbor's side of a shared low point, or a site plan may show a swale that no longer lines up once the final roof layout shifts a downspout during construction documents.
Other common issues include roof discharge aimed at a foundation planting bed with no clear path away from the structure, or a grading plan that assumes even sheet flow across the yard without accounting for the concentrated volume a roof downspout actually delivers at one point. These are the kinds of details a single coordination drawing is meant to catch before they become field problems.
- Downspout discharge points that were never checked against final site grading.
- Grading plans that assume even sheet flow but do not account for concentrated roof discharge.
- Drainage directed toward a foundation, planting bed, or neighboring property without a clear path away.
- Site plan revisions made after the roof plan was finalized, without updating drainage assumptions.
Questions for the Responsible Authority or Qualified Professional
Because stormwater requirements are set by the applicable jurisdiction and can change, a property owner working in Charlotte, York County, or any nearby jurisdiction should confirm the current, project-specific requirements directly with that authority before finalizing a design. The published pages from Charlotte and York County are a starting point for understanding that a formal review process exists, not a substitute for a jurisdiction's current submittal checklist.
A licensed engineer, surveyor, or qualified site designer is generally the right professional to confirm whether a project triggers formal stormwater plan review, what documentation is required, and how roof discharge should be treated within that jurisdiction's stormwater program. Any property-specific code, environmental, or engineering question should go to that authority or professional rather than being answered by general educational content.
- Does this project trigger formal stormwater plan review under the applicable jurisdiction?
- What documentation does the authority require regarding roof discharge and site grading?
- Are there specific setback, easement, or discharge-point requirements for this property?
- What is the current process for submitting and revising a stormwater plan if conditions change?
Next Action and Related CDG Service Resource
A roof and site drainage coordination checklist is most useful early, before a roof plan and a grading plan have already been finalized separately. Reviewing both documents together, tracing every downspout to its final discharge point, and confirming that path makes sense across the finished lot is a practical planning step that supports whatever formal stormwater review a jurisdiction ultimately requires.
Property owners planning new construction or major site work in the Lake Wylie area can review CDG's site planning service page for general information on how site planning fits into a project. For additional background on drainage, grading, and related topics, the CDG blog includes further educational articles, and property owners with project-specific questions are welcome to reach out through the consultation page to discuss general planning next steps.
- Review the roof plan and site grading plan together before either is finalized.
- Confirm every downspout has a traceable path to a specific discharge point.
- Visit the site planning service page for general information relevant to Lake Wylie area projects.
- Use the consultation page to discuss general project planning questions with CDG.
Questions homeowners ask
Why can't the roof plan and site grading plan just be reviewed separately by each designer?
They can be drawn separately, but reviewing them only in isolation makes it easy to miss where a downspout's discharge point does not actually line up with the finished grade shown on the site plan. A combined roof and site drainage coordination review is a practical way to catch that gap before construction, even though each plan may still be produced by a different discipline.
Does a coordination drawing replace a formal stormwater plan required by a city or county?
No. A coordination drawing is a planning-level tool that helps a project team confirm roof discharge and site grading agree with each other. Whether a formal stormwater plan is required, and what that plan must contain, is determined by the applicable jurisdiction, such as the City of Charlotte or York County, and must be confirmed with that authority directly.
Who is responsible for making sure roof drainage and site drainage are coordinated?
This can vary by project, since the architect or designer typically controls the roof plan while a civil designer or engineer typically controls the site grading plan. Setting a clear hold point where both plans are reviewed together, and assigning someone the responsibility to confirm that review happens, helps avoid the two documents being finalized without ever being compared.
What should a property owner do if roof drainage and site grading seem to conflict on the plans?
The conflict should be raised with whoever controls each affected plan, typically the designer for the roof plan and the engineer or site designer for the grading plan, so it can be resolved before construction. Any question about whether the resolution meets a jurisdiction's stormwater requirements should be directed to the responsible authority having jurisdiction or a licensed professional familiar with that jurisdiction's current standards.
Plan the next step
Use this article as a planning aid, then confirm project-specific requirements with the responsible authority and qualified professionals. Review CDG's related service, construction articles, or consultation page when you are ready to organize the next decision.
Official sources and verification
Authority pages, forms, fees, review steps, and code references can change. Verify the current path for the property and scope before relying on a planning assumption.