What is a common plan of development?

The rule that surprises the most builders: your small lot can still need a SWPPP if it is part of a larger development.

This is the rule that surprises more Tennessee builders than any other: your lot can be well under an acre and still need a SWPPP. The reason is the "common plan of development or sale."

The concept

Permit coverage is triggered at one acre of disturbance. But the acre is measured across the larger common plan, not just your individual parcel. If your lot is part of a development that, as a whole, disturbs one acre or more, your lot is generally covered even if it alone disturbs a fraction of an acre.

Common examples

• A single lot in a subdivision. The subdivision was designed and platted as one development; each lot is part of that common plan.
• A phased project. Building out in phases does not reset the acre count; the overall plan controls.
• A business park or multi-building site developed under one plan.

Why it catches people

An individual homebuilder looks at their own small lot and reasonably assumes they are under the threshold. But regulators look at the whole platted development. That gap is exactly where unpermitted disturbance, and violations, happen.

How to tell if it applies

Ask: was the larger tract subdivided, platted, or marketed as a single development? Is there a master plan, a subdivision plat, or common infrastructure? If yes, and the whole disturbs an acre or more, assume your lot is covered and confirm with your local authority or TDEC.

What to do

Get coverage. For eligible at-grade single-family lots, TDEC's CN-1249 homebuilder SWPPP is the streamlined path, and SWPPP Builder generates it for you.