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Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Federal Rule Requirements for Unpaved Parking Lots, Unpaved Roads, and Vacant Lots in Maricopa County

These requirements apply to:

  • Owners/operators of unpaved parking lots
  • Owners/operators of unpaved roads
  • Owners/operators of disturbed vacant lots
  • Responsible parties for weed abatement on vacant lots
  • Does not apply to any of the above who are already covered under a Dust Control Plan in a permit issued by Maricopa County Environmental Services Department


General requirements

Unpaved Parking Lots
Pave, apply chemical/organic stabilizers or gravel by May 2, 1999. For lots used no more than 35 days a year, stabilize the surface on any days when over 100 vehicles are parked in the lot. Lots that are less than 5000 square feet or are low-usage (10 or fewer cars per day) are exempt.

Unpaved Roads
Pave, apply chemical/organic stabilizers or gravel unpaved roads which receive 250 or more vehicle trips per day, by June 10, 2000.

Vacant lots: Weed Removal
Stabilize the surface with a dust suppressant before or during weed removal. Prevent or eliminate the tracking of dust onto paved surfaces. Stabilize the disturbed surface immediately after the weed removal by compacting the ground or applying gravel or dust suppressants. Weed removal operations that disturb less than 0.5 acres are exempt.

Vacant lots: Disturbed Surfaces
Revegetate, apply water or chemical/organic stabilizers, restore to a natural state or gravel by May 2, 1999 or within 60 days following a disturbance, whichever is later. Vacant lots with less than 0.5 acres of disturbed surface are exempt.

Vacant Lots: Motor Vehicle Trespass
Place fencing, trees, or other barriers to prevent vehicle access, or apply gravel or chemical/organic stabilizers by May 2, 1999 or within 60 days following a disturbance, whichever is later. Vacant lots with less than 5,000 square feet of disturbed surface are exempt.

Alternative Control Measures
Owners/operators may use other control measures as long as the surface is stabilized.

Stabilizers or Gravel
Chemical stabilizers or gravel must be periodically maintained to stabilize the surface in accordance with the rule's test methods.

For more information:

Please contact colleen McKaughan, Associate Director, air Division, U.S. EPA Region 9 at (520) 498-0118. Send questions and comments to r9.phoenixdust@epa.gov.

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