Sediment Control BMPs: Perimeter Controls, Track-Out, Inlet Protection and Basins

Sediment control practices slow runoff enough for soil particles to settle out, or filter them out, before water leaves the disturbed area. They work best for coarser particles. Fine silts and clays pass through many controls, which is why erosion control comes first.

Natural buffers

For discharges to receiving waters within 50 feet of the site's earth disturbance, the EPA CGP requires one of three options: keep a 50-foot undisturbed natural buffer; keep a smaller buffer supplemented by controls that together achieve the same sediment reduction; or, if no buffer is feasible, use controls that achieve the sediment load reduction equivalent to a 50-foot buffer.

Perimeter controls

The CGP requires sediment controls along perimeter areas downslope of exposed soil. Examples include silt fence, wire-backed silt fence, fiber rolls (wattles), compost filter socks, and filter berms. The permit says to:

• Install them upgradient of any natural buffer.
• Install them on the contour and extend both ends up slope (for example, at 45 degrees), forming a crescent instead of a straight line, so water can't run around the ends.
• Remove sediment before it accumulates to one-half of the above-ground height of the control.
• After a storm, if water is going around or under the control, extend or repair it.

Construction exits and track-out

Mud tracked onto roads washes straight into storm drains. The CGP requires operators to:

• Restrict vehicles to designated exit points.
• Stabilize exit points onto paved roads, for example with aggregate stone over geotextile, or construction mats.
• Add track-out controls as needed, such as wheel washes, rumble racks or shaker plates.
• Remove tracked-out sediment by the end of the same business day (or by the end of the next business day if it happens on a non-business day), by sweeping, shoveling or vacuuming. Hosing or sweeping it into a storm drain is prohibited.

Stockpiles

For soil stockpiles and land-clearing debris piles, the CGP requires:

• Locate them outside natural buffers and away from drainage features, storm drain inlets and concentrated flow.
• Install a sediment barrier along all downgradient sides.
• For piles unused for 14 or more days, provide cover or temporary stabilization.

Storm drain inlet protection

Install inlet protection on any storm drain inlet that carries stormwater from the site to a receiving water, where you have authority to access it (unless the inlet drains to a sediment basin or similar control). Clean or replace inlet protection as sediment builds up, filters clog or performance drops, and remove sediment that accumulates next to the inlet by the end of the same business day (or the next business day if same-day isn't feasible). Common devices: filter bags in the grate, curb inlet socks, gravel and wire mesh, and block-and-gravel filters.

Sediment traps and basins

Traps and basins pond runoff so sediment settles. If you install a sediment basin or similar impoundment under the EPA CGP:

• Locate it outside receiving waters and natural buffers, and avoid collecting water from wetlands.
• Provide storage for either the runoff from a 2-year, 24-hour storm or 3,600 cubic feet per acre drained.
• Use outlets that withdraw water from the surface (such as skimmers) unless infeasible, since the cleanest water is at the top.
• Use erosion controls and velocity dissipation at inlets and outlets.
• Maintain it so sediment storage capacity is kept.

Size one with the sediment basin calculator.

Key takeaways

• Keep a 50-foot natural buffer to nearby waters or provide equivalent controls.
• Perimeter controls go on the contour with ends turned up slope; clean them before sediment reaches half the height.
• Stabilize exits and remove track-out by the end of the same business day. Never hose it into a drain.
• Stockpiles need downgradient barriers, and cover if unused 14 days or more.
• Basins: 2-year, 24-hour storm volume or 3,600 cubic feet per acre drained, with surface outlets.

Last reviewed: October 25, 2026 · Free general education based on the Clean Water Act, EPA NPDES rules and the EPA Construction General Permit. Your governing permit (EPA, state, tribal or local) controls. This is not legal advice, not EPA-approved, and not a California QSP/QSD or other state credential, and it does not issue a certificate. Nothing you enter on this page is saved or sent.