40 C.F.R. § 1090.285
For purposes of this part, the RFG covered areas are as follows:
Table 1 to Paragraph (a)-RFG Covered Areas Under 42 U.S.C. 7545(k)(10)(D)
| Area designation | State | Counties | Independent cities |
| Los Angeles-Anaheim-Riverside | California | Los Angeles, Orange, Ventura, San Bernardino,1 Riverside2 | |
| San Diego County | California | San Diego | |
| Greater Connecticut | Connecticut | Hartford, Middlesex, New Haven, New London, Tolland, Windham, Fairfield (only the City of Shelton), Litchfield (all except the towns of Bridgewater and New Milford) | |
| New York-Northern New Jersey-Long Island-Connecticut | Connecticut | Fairfield (all except the City of Shelton), Litchfield (only the towns of Bridgewater and New Milford) | |
| New Jersey | Bergen, Essex, Hudson, Hunterdon, Middlesex, Monmouth, Morris, Ocean, Passaic, Somerset, Sussex, Union | ||
| New York | Bronx, Kings, Nassau, New York, Orange, Putnam, Queens, Richmond, Rockland, Suffolk, Westchester | ||
| Philadelphia-Wilmington-Trenton | Delaware | Kent, New Castle | |
| Maryland | Cecil | ||
| New Jersey | Burlington, Camden, Cumberland, Gloucester, Mercer, Salem | ||
| Pennsylvania | Bucks, Chester, Delaware, Montgomery, Philadelphia | ||
| Chicago-Gary-Lake County | Illinois | Cook, Du Page, Kane, Lake, McHenry, Will, Grundy (only Aux Sable Township and Goose Lake Township), Kendall (only Oswego Township) | |
| Indiana | Lake, Porter | ||
| Baltimore | Maryland | Anne Arundel, Baltimore, Carroll, Harford, Howard | Baltimore. |
| Houston-Galveston-Brazoria | Texas | Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, Waller | |
| Milwaukee-Racine | Wisconsin | Kenosha, Milwaukee, Ozaukee, Racine, Washington, Waukesha |
1 That portion of San Bernardino County, CA that lies south of latitude 35 degrees, 10 minutes north and west of longitude 115 degrees, 45 minutes west.
2 That portion of Riverside County, CA that lies to the west of a line described as follows: Beginning at the northeast corner of Section 4, Township 2 South, Range 5 East, a point on the boundary line common to Riverside and San Bernardino Counties; then southerly along section lines to the centerline of the Colorado River Aqueduct; then southeasterly along the centerline of said Colorado River Aqueduct to the southerly line of Section 36, Township 3 South, Range 7 East; then easterly along the township line to the northeast corner of Section 6, Township 4 South, Range 9 East; then southerly along the easterly line of Section 6 to the southeast corner thereof; then easterly along section lines to the northeast corner of Section 10, Township 4 South, Range 9 East; then southerly along section lines to the southeast corner of Section 15, Township 4 South, Range 9 East; then easterly along the section lines to the northeast corner of Section 21, Township 4 South, Range 10 East; then southerly along the easterly line of Section 21 to the southeast corner thereof; then easterly along the northerly line of Section 27 to the northeast corner thereof; then southerly along section lines to the southeast corner of Section 34, Township 4 South, Range 10 East; then easterly along the township line to the northeast corner of Section 2, Township 5 South, Range 10 East; then southerly along the easterly line of Section 2, to the southeast corner thereof; then easterly along the northerly line of Section 12 to the northeast corner thereof; then southerly along the range line to the southwest corner of Section 18, Township 5 South, Range 11 East; then easterly along section lines to the northeast corner of Section 24, Township 5 South, Range 11 East; and then southerly along the range line to the southeast corner of Section 36, Township 8 South, Range 11 East, a point on the boundary line common to Riverside and San Diego Counties.
Table 2 to Paragraph (b)-Additional RFG Covered Areas Under 42 U.S.C. 7545(k)(10)(D)
| Area designation | State or district | Counties | Independent cities |
| Washington, DC-Maryland-Virginia | District of Columbia | Washington | |
| Maryland | Calvert, Charles, Frederick, Montgomery, Prince George's | ||
| Virginia | Arlington, Fairfax, Loudoun, Prince William, Stafford | Alexandria, Fairfax, Falls Church, Manassas, Manassas Park. | |
| Sacramento Metro | California | Sacramento, Yolo, El Dorado (except Lake Tahoe and its drainage area), Placer,1 Solano,2 Sutter3 | |
| San Joaquin Valley | California | Fresno, Kings, Madera, Merced, San Joaquin, Stanislaus, Tulare, Kern4 | |
| Eastern Kern County | California | Kern County5 | |
| Dallas | Texas | Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant, Wise | |
| Denver-Boulder-Greeley-Ft. Collins-Loveland | Colorado | Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Jefferson, Larimer County,6 Weld County7 |
1 All portions of Placer County except that portion of the County within the drainage area naturally tributary to Lake Tahoe including said Lake, plus that area in the vicinity of the head of the Truckee River described as follows: Commencing at the point common to the aforementioned drainage area crestline and the line common to Townships 15 North and 16 North, Mount Diablo Base and Meridian (M.D.B.&M.), and following that line in a westerly direction to the northwest corner of Section 3, Township 15 North, Range 16 East, M.D.B.&M., thence south along the west line of Sections 3 and 10, Township 15 North, Range 16 East, M.D.B.&M., to the intersection with the said drainage area crestline, thence following the said drainage area boundary in a southeasterly, then northeasterly direction to and along the Lake Tahoe Dam, thence following the said drainage area crestline in a northeasterly, then northwesterly direction to the point of beginning.
2 That portion of Solano County that lies north and east of a line described as follows: Beginning at the intersection of the westerly boundary of Solano County and the 1/4 section line running east and west through the center of Section 34; T. 6 N., R. 2 W., M.D.B.&M.; thence east along said 1/4 section line to the east boundary of Section 36, T. 6 N., R. 2 W.; thence south 1/2 mile and east 2.0 miles, more or less, along the west and south boundary of Los Putos Rancho to the northwest corner of Section 4, T. 5 N., R. 1 W.; thence east along a line common to T. 5 N. and T. 6 N. to the northeast corner of Section 3, T. 5 N., R. 1 E.; thence south along section lines to the southeast corner of Section 10, T. 3 N., R. 1 E.; thence east along section lines to the south 1/4 corner of Section 8, T. 3 N., R. 2 E.; thence east to the boundary between Solano and Sacramento Counties.
3 That portion of Sutter County south of a line connecting the northern border of Yolo Co. to the SW tip of Yuba Co. and continuing along the southern Yuba Co. border to Placer Co.
4 Boundary between the Kern County and San Joaquin Valley air districts that generally follows the ridge line of the Sierra Nevada and Tehachapi Mountain Ranges. That portion of Kern County that lies west and north of a line described as follows: Beginning at the Kern-Los Angeles County boundary and running north and east along the northwest boundary of the Rancho La Liebre Land Grant to the point of intersection with the range line common to Range 16 West and Range 17 West, San Bernardino Base and Meridian; north along the range line to the point of intersection with the Rancho El Tejon Land Grant boundary; then southeast, northeast, and northwest along the boundary of the Rancho El Tejon Grant to the northwest corner of Section 3, Township 11 North, Range 17 West; then west 1.2 miles; then north to the Rancho El Tejon Land Grant boundary; then northwest along the Rancho El Tejon line to the southeast corner of Section 34, Township 32 South, Range 30 East, Mount Diablo Base and Meridian; then north to the northwest corner of Section 35, Township 31 South, Range 30 East; then northeast along the boundary of the Rancho El Tejon Land Grant to the southwest corner of Section 18, Township 31 South, Range 31 East; then east to the southeast corner of Section 13, Township 31 South, Range 31 East; then north along the range line common to Range 31 East and Range 32 East, Mount Diablo Base and Meridian, to the northwest corner of Section 6, Township 29 South, Range 32 East; then east to the southwest corner of Section 31, Township 28 South, Range 32 East; then north along the range line common to Range 31 East and Range 32 East to the northwest corner of Section 6, Township 28 South, Range 32 East; then west to the southeast corner of Section 36, Township 27 South, Range 31 East; then north along the range line common to Range 31 East and Range 32 East to the Kern-Tulare County boundary.
5 That portion of the county (with the exception of that portion in Hydrologic Unit Number 18090205 the Indian Wells Valley) east and south of a line described as follows: Beginning at the Kern-Los Angeles County boundary and running north and east along the northwest boundary of the Rancho La Liebre Land Grant to the point of intersection with the range line common to Range 16 West and Range 17 West, San Bernardino Base and Meridian; north along the range line to the point of intersection with the Rancho El Tejon Land Grant boundary; then southeast, northeast, and northwest along the boundary of the Rancho El Tejon Grant to the northwest corner of Section 3, Township 11 North, Range 17 West; then west 1.2 miles; then north to the Rancho El Tejon Land Grant boundary; then northwest along the Rancho El Tejon line to the southeast corner of Section 34, Township 32 South, Range 30 East, Mount Diablo Base and Meridian; then north to the northwest corner of Section 35, Township 31 South, Range 30 East; then northeast along the boundary of the Rancho El Tejon Land Grant to the southwest corner of Section 18, Township 31 South, Range 31 East; then east to the southeast corner of Section 13, Township 31 South, Range 31 East; then north along the range line common to Range 31 East and Range 32 East, Mount Diablo Base and Meridian, to the northwest corner of Section 6, Township 29 South, Range 32 East; then east to the southwest corner of Section 31, Township 28 South, Range 32 East; then north along the range line common to Range 31 East and Range 32 East to the northwest corner of Section 6, Township 28 South, Range 32 East, then west to the southeast corner of Section 36, Township 27 South, Range 31 East, then north along the range line common to Range 31 East and Range 32 East to the Kern-Tulare County boundary.
6 That portion of the county that lies south of a line described as follows: Beginning at a point on Larimer County's eastern boundary and Weld County's western boundary intersected by latitude 40 degrees, 42 minutes, and 47.1 seconds north, proceed west to a point defined by the intersection of latitude 40 degrees, 42 minutes, 47.1 seconds north and longitude 105 degrees, 29 minutes, and 40.0 seconds west, proceeding south on longitude 105 degrees, 29 minutes, 40.0 seconds west to the intersection with latitude 40 degrees, 33 minutes and 17.4 seconds north, proceeding west on latitude 40 degrees, 33 minutes, 17.4 seconds north until this line intersects Larimer County's western boundary and Grand County's eastern boundary.
7 That portion of the county that lies south of a line described as follows: Beginning at a point on Weld County's eastern boundary and Logan County's western boundary intersected by latitude 40 degrees, 42 minutes, 47.1 seconds north, proceeding west on latitude 40 degrees, 42 minutes, 47.1 seconds north until this line intersects Weld County's western boundary and Larimer County's eastern boundary.
Table 3 to Paragraph (c)-RFG Covered Areas Under 42 U.S.C. 7545(k)(6)(A)(i)
| Area designation at the time of opt-in | State | Counties | Independent cities |
| Sussex County | Delaware | Sussex | |
| St. Louis, Missouri-Illinois | Illinois | Jersey, Madison, Monroe, St. Clair | |
| Missouri | Franklin, Jefferson, St. Charles, St. Louis | St. Louis. | |
| Kentucky portion of Louisville | Kentucky | Jefferson, Bullitt,1 Oldham2 | |
| Kent and Queen Anne's Counties | Maryland | Kent, Queen Anne's | |
| Statewide | Massachusetts | All | |
| Strafford, Merrimack, Hillsborough, Rockingham Counties | New Hampshire | Hillsborough, Merrimack, Rockingham, Strafford | |
| Atlantic City | New Jersey | Atlantic, Cape May | |
| New Jersey portion of Allentown- Bethlehem-Easton | New Jersey | Warren | |
| Dutchess County | New York | Dutchess | |
| Essex County | New York | Essex (the portion of Whiteface Mountain above 4,500 feet in elevation) | |
| Statewide | Rhode Island | All | |
| Norfolk-Virginia Beach, Newport News (Hampton Roads) | Virginia | James City, York | Chesapeake, Hampton, Newport News, Norfolk, Poquoson, Portsmouth, Suffolk, Virginia Beach, Williamsburg. |
| Richmond | Virginia | Charles City, Chesterfield, Hanover, Henrico | Colonial Heights, Hopewell, Richmond. |
1 In Bullitt County, KY, beginning at the intersection of Ky 1020 and the Jefferson-Bullitt County Line proceeding to the east along the county line to the intersection of county road 567 and the Jefferson-Bullitt County Line; proceeding south on county road 567 to the junction with Ky 1116 (also known as Zoneton Road); proceeding to the south on KY 1116 to the junction with Hebron Lane; proceeding to the south on Hebron Lane to Cedar Creek; proceeding south on Cedar Creek to the confluence of Floyds Fork turning southeast along a creek that meets Ky 44 at Stallings Cemetery; proceeding west along Ky 44 to the eastern most point in the Shepherdsville city limits; proceeding south along the Shepherdsville city limits to the Salt River and west to a point across the river from Mooney Lane; proceeding south along Mooney Lane to the junction of Ky 480; proceeding west on Ky 480 to the junction with Ky 2237; proceeding south on Ky 2237 to the junction with Ky 61 and proceeding north on Ky 61 to the junction with Ky 1494; proceeding south on Ky 1494 to the junction with the perimeter of the Fort Knox Military Reservation; proceeding north along the military reservation perimeter to Castleman Branch Road; proceeding north on Castleman Branch Road to Ky 44; proceeding a very short distance west on Ky 44 to a junction with Ky 1020 and proceeding north on Ky 1020 to the beginning.
2 In Oldham County, KY, beginning at the intersection of the Oldham-Jefferson County Line with the southbound lane of Interstate 71; proceeding to the northeast along the southbound lane of Interstate 71 to the intersection of Ky 329 and the southbound lane of Interstate 71; proceeding to the northwest on Ky 329 to the intersection of Zaring Road on Ky 329; proceeding to the east-northeast on Zaring Road to the junction of Cedar Point Road and Zaring Road; proceeding to the north-northeast on Cedar Point Road to the junction of Ky 393 and Cedar Point Road; proceeding to the south-southeast on Ky 393 to the junction of county road 746 (the road on the north side of Reformatory Lake and the Reformatory); proceeding to the east-northeast on county road 746 to the junction with Dawkins Lane (also known as Saddlers Mill Road) and county road 746; Proceeding to follow an electric power line east-northeast across from the junction of county road 746 and Dawkins Lane to the east-northeast across Ky 53 on to the La Grange Water Filtration Plant; proceeding on to the east-southeast along the power line then south across Fort Pickens Road to a power substation on Ky 146; proceeding along the power line south across Ky 146 and the Seaboard System Railroad track to adjoin the incorporated city limits of La Grange; then proceeding east then south along the La Grange city limits to a point abutting the north side of Ky 712; proceeding east-southeast on Ky 712 to the junction of Massie School Road and Ky 712; proceeding to the south-southwest and then north-northwest on Massie School Road to the junction of Ky 53 and Massie School Road; proceeding on Ky 53 to the north-northwest to the junction of Moody Lane and Ky 53; proceeding on Moody Lane to the south-southwest until meeting the city limits of La Grange; then briefly proceeding north following the La Grange city limits to the intersection of the northbound lane of Interstate 71 and the La Grange city limits; proceeding southwest on the northbound lane of Interstate 71 until intersecting with the North Fork of Currys Fork; proceeding south-southwest beyond the confluence of Currys Fork to the south-southwest beyond the confluence of Floyds Fork continuing on to the Oldham-Jefferson County Line and proceeding northwest along the Oldham-Jefferson County Line to the beginning.
40 C.F.R. §1090.285