Drainage Permits in Davidson County, TN: What You Need to Know
Most residential french drain installations in Nashville don't require a permit. Here's exactly when one is needed, and who issues it.
The most common question Nashville homeowners ask before hiring a drainage contractor: "Do I need a permit?" In most cases, the answer is no. Metro Nashville's grading permit threshold, 10,000 square feet of disturbed area or 100 cubic yards of moved soil, is designed for larger construction activity, not the narrow trenches of a residential french drain.
That said, there are situations where permits are required: properties in flood zones, work that connects to the municipal storm system, or projects that are part of larger land disturbance. The table below covers every scenario.
Permit Requirements for Drainage Work in Davidson County
| Project Condition | Permit Required |
|---|---|
| Land disturbance ≥ 10,000 sq ft | Metro Grading Permit |
| Soil displacement ≥ 100 cubic yards | Metro Grading Permit |
| Connection to municipal storm drain | Storm Drain Connection Permit |
| Work in FEMA floodplain (Zone A/AE) | Floodplain Development Permit |
| Construction site ≥ 1 acre total disturbance | NPDES Construction Stormwater Permit |
| Typical residential french drain (< 10,000 sq ft) | No permit required |
Official Sources for Davidson County Drainage Permits
Metro Nashville Public Works issues grading permits for projects that disturb 10,000 or more square feet of land or move 100 or more cubic yards of soil. Most residential french drain installations fall below both thresholds. For project-specific confirmation:
Metro Nashville: Who Needs a Grading Permit? →Metro Water Services handles stormwater infrastructure connections and floodplain development permits for Davidson County properties. Contact them for projects connecting to the municipal storm drain system or in flood zones:
Metro Nashville Water Services, Stormwater →Check whether your Davidson County property is in a FEMA-designated Special Flood Hazard Area. Any grading or fill work in Zone A or Zone AE requires a local floodplain development permit regardless of project size:
FEMA Flood Map Service Center →Tennessee's NPDES construction stormwater permit program applies to projects disturbing one acre or more. Residential french drains are far below this threshold. For projects part of larger construction activity:
TDEC NPDES Stormwater Permitting Program →What “10,000 Square Feet” Means in Practice
10,000 square feet is roughly 100 feet by 100 feet, nearly a quarter acre of disturbed surface. A french drain trench is typically 12 to 18 inches wide. Even a 200-foot drain run only disturbs about 250 to 300 square feet of surface area. The volume of excavated soil from a standard residential french drain is typically 3 to 8 cubic yards, compared to the 100-cubic-yard permit threshold.
The 10,000 sq ft threshold was designed for subdivision grading, commercial site preparation, and other large-scale earthwork. Standard residential drainage installations, yard drains, foundation perimeter drains, downspout extensions, do not approach that scale.
When to Call Metro Before Starting Work
Even when a permit isn't required, there are situations where it's worth a call to Metro before starting:
- Your property is near a creek, stream, or wetland area, check the FEMA map first
- The natural drainage outlet for your system would cross a neighbor's property (drainage easement may be required)
- You're in a neighborhood with a stormwater management district or HOA covenant
- The drainage work is connected to a new home construction project
- Your lot is within a designated greenway buffer or conservation easement
We assess every job before quoting. If your project triggers a permit requirement, we identify it upfront, no surprises mid-project.