U.S. Stormwater Regulation Directory

Agency: ADEM

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale

Agency: DEC

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale

Agency: ADEQ

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale

Agency: DEQ

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre

Agency: SWRCB

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan)

Agency: CDPHE WQCD

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development exceeding 1 acre)

Agency: DEEP

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale; also applies to any dewatering discharges from construction sites of any size

Agency: DNREC

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale)

Agency: FDEP

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan)

Agency: EPD

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale); ≥ 5 acres triggers additional land disturbance activity permit requirements under state law

Agency: DOH-CWB

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale); some activities < 1 acre may require an individual NPDES permit depending on proximity to sensitive waters

Agency: IDEQ

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale); disturbing < 1 acre may still require coverage if DEQ determines the site poses a risk to water quality

Agency: IEPA

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale); Chicago Metropolitan Agency for Planning (CMAP) area may have additional requirements through local MS4 permits

Agency: IDEM

Threshold: ≥ 1 acre of land disturbance; < 1 acre if part of a larger common plan of development or sale

Agency: IDNR

Threshold: ≥ 1 acre of land disturbance; < 1 acre if part of a larger common plan of development or sale

Agency: KDHE

Threshold: ≥ 1 acre of land disturbance; < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre

Agency: DOW

Threshold: ≥ 1 acre of land disturbance; < 1 acre if part of a larger common plan of development or sale expected to disturb ≥ 1 acre in total

Agency: LDEQ

Threshold: ≥ 1 acre of land disturbance; < 1 acre if part of a larger common plan of development or sale that will disturb ≥ 1 acre in total

Agency: DEP

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale)

Agency: MDE

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale); sites disturbing < 5,000 sq ft in certain Priority Protection Areas may also require coverage

Agency: MassDEP

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale); Massachusetts also requires coverage for sites that are within certain Zone II (public water supply) or Interim Wellhead Protection Areas regardless of acreage

Agency: EGLE

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale); Michigan also requires permit coverage for any activity that discharges to a water of the state with potential to cause or contribute to a water quality violation

Agency: MPCA

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale); Minnesota's permit also applies to all construction activity that discharges to a Special Water or impaired water regardless of acreage

Agency: MDEQ

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre)

Agency: MDNR

Threshold: ≥ 1 acre of total land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre); also applies to any earth-disturbing activity that the Director determines has the potential to cause water quality violations

Agency: MT DEQ

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre); individual construction sites < 1 acre may also require coverage if they discharge to impaired waters

Agency: NDEE

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre)

Agency: NDEP

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre). Note: Nevada is a predominantly arid state, and many small sites that would not generate discharge in wetter climates are still required to obtain coverage.

Agency: NHDES

Threshold: ≥ 1 acre of land disturbance; also applies to sites < 1 acre that are part of a larger common plan of development. Separately, NH RSA 485-A:17 (Alteration of Terrain) requires permit for disturbing ≥ 50,000 sq ft (≈1.15 acres) or within 250 ft of a surface water.

Agency: NJDEP

Threshold: ≥ 1 acre of total land disturbance, or < 1 acre if part of a larger common plan of development or sale that will disturb ≥ 1 acre in total. Individual lot disturbances < 1 acre in a larger subdivision require coverage.

Agency: NMED

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre. Sites < 1 acre not part of a larger plan are regulated by NMED on a case-by-case basis if they discharge to waters of New Mexico.

Agency: NYSDEC

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan)

Agency: NCDEQ

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale that will disturb ≥ 1 acre. NC also regulates land-disturbing activity ≥ 500 sq ft under the NC Sedimentation Pollution Control Act (SPCA) of 1973, which is a parallel but distinct state requirement.

Agency: NDDEQ

Threshold: ≥ 1 acre of total land disturbance, or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre. Linear projects (pipelines, roads) use total disturbance area for threshold calculation.

Agency: Ohio EPA

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre

Agency: ODEQ

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre

Agency: Oregon DEQ

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre; projects < 1 acre not part of a common plan are generally exempt from 1200-C

Agency: PA DEP

Threshold: ≥ 1 acre of earth disturbance, or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre; Pennsylvania also requires a separate E&S permit (via Chapter 102) for all earth disturbance ≥ 5,000 sq ft (approximately 0.11 acre)

Agency: RIDEM

Threshold: ≥ 1 acre of land disturbance, or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre

Agency: SCDES

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre)

Agency: DANR

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre); sites disturbing ≥ 5 acres that discharge to waters of the state require a Notice of Intent

Agency: TDEC

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre); all sites must also comply with Tennessee's Construction General Permit and the Stormwater Management Act

Agency: TCEQ

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development)

Agency: UDEQ

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre); Utah administers this under its own UPDES (Utah Pollutant Discharge Elimination System) program, which is the state equivalent of NPDES

Agency: DEC

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre); Vermont also regulates stormwater from smaller sites through its municipal stormwater program and Act 250 land use review process; sites disturbing ≥ 1 acre in regulated watersheds may face additional requirements under the Vermont Stormwater Management Rule

Agency: VDEQ

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre)

Agency: Ecology

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan)

Agency: WVDEP

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre)

Agency: WDNR

Threshold: ≥ 1 acre of land disturbance; also applies to sites < 1 acre that are part of a larger common plan of development or sale disturbing ≥ 1 acre; Wisconsin additionally requires a Notice of Intent for sites disturbing ≥ 4,000 sq ft in certain MS4 areas under local ordinance (not state permit threshold)

Agency: WDEQ

Threshold: ≥ 1 acre of land disturbance (or < 1 acre if part of a larger common plan of development or sale that will ultimately disturb ≥ 1 acre)