| Chapter 20-1. AIR QUALITY - GENERAL RULES |
| Chapter 20-2. AIR QUALITY - GENERAL AND NON-ATTAINMENT AREA PERMITS |
| Chapter 20-3. AIR QUALITY - OPERATING PERMITS AND ACID RAIN PROGRAMS |
| Chapter 20-4. AIR QUALITY - AMBIENT MONITORING, EMERGENCY PROCEDURES, AND CHEMICAL ACCIDENT PREVENTION |
| Chapter 20-5. AIR QUALITY - SOURCE MONITORING AND TESTING |
| Chapter 20-6. AIR QUALITY - PARTICULATES |
| Chapter 20-7. AIR QUALITY - VOLATILE ORGANIC COMPOUNDS AND HAZARDOUS AIR POLLUTANTS |
| Chapter 20-8. AIR QUALITY - ASBESTOS, SULFUR, NITROGEN OXIDES, AND LEAD |
| Chapter 20-9. AIR QUALITY - MOTOR VEHICULAR POLLUTANTS, LEAD, ODORS, AND NUISANCE POLLUTANTS |
| Chapter 20-10. AIR QUALITY - NITROGEN OXIDES EMISSIONS BUDGET PROGRAM |
| Chapter 20-14. AIR TOXICS AND HAZARDOUS AIR POLLUTANTS |
| Chapter 20-15. AIR QUALITY - GENERAL AND TRANSPORTATION CONFORMITY |
| Chapter 20-21. SMOKING REGULATIONS |
| Chapter 20-22. PESTICIDE CONTROL - GENERAL RULES |
| Chapter 20-23. PESTICIDE CONTROL - APPLICATORS |
| Chapter 20-24. PESTICIDE CONTROL - OPERATORS |
| Chapter 20-25. PESTICIDE CONTROL - ADMINISTRATION AND ENFORCEMENT |
| Chapter 20-26. FIRE-STANDARD-COMPLIANT CIGARETTES |
| Chapter 20-27. NOISE CONTROL |
| Chapter 20-28. MAXIMUM NOISE LEVELS |
| Chapter 20-29. NOISE MEASURING TEST PROCEDURES |
| Chapter 20-31. FLOOD HAZARD RULES |
| Chapter 20-32. MOLD AND RADON LICENSURE AND CERTIFICATION |
| Chapter 20-33. REGULATION OF LEAD-BASED PAINT ACTIVITIES |
| Chapter 20-34. ENERGY CONSERVATION DEMONSTRATION AWARDS PROGRAM |
| Chapter 20-35. GREEN BUILDING REQUIREMENTS |
| Chapter 20-36. ENERGY ASSISTANCE AND CONSERVATION PROGRAMS |
| Chapter 20-40. PAINT STEWARDSHIP |
| Chapter 20-41. ELECTRONICS STEWARDSHIP |
| Chapter 20-42. HAZARDOUS WASTE MANAGEMENT - STANDARDS FOR THE MANAGEMENT OF HAZARDOUS WASTE AND USED OIL |
| Chapter 20-43. HAZARDOUS WASTE MANAGEMENT - ADMINISTRATION AND ENFORCEMENT |
| Chapter 20-55. UNDERGROUND STORAGE TANKS - GENERAL PROVISIONS |
| Chapter 20-56. UNDERGROUND STORAGE TANKS - TANK NOTIFICATION AND REGISTRATION, RECORDKEEPING, REPORTS, AND NOTICES |
| Chapter 20-57. UNDERGROUND STORAGE TANKS - NEW TANK PERFORMANCE STANDARDS |
| Chapter 20-58. UNDERGROUND STORAGE TANKS - UPGRADES OF EXISTING USTS |
| Chapter 20-59. UNDERGROUND STORAGE TANKS - OPERATION AND MAINTENANCE OF USTS |
| Chapter 20-60. UNDERGROUND STORAGE TANKS - RELEASE DETECTION |
| Chapter 20-61. UNDERGROUND STORAGE TANKS - OUT-OF-SERVICE AND CLOSURE OF UST SYSTEMS |
| Chapter 20-62. UNDERGROUND STORAGE TANKS - REPORTING OF RELEASES, INVESTIGATION, CONFIRMATION, ASSESSMENT AND CORRECTIVE ACTION |
| Chapter 20-63. UNDERGROUND STORAGE TANKS - GENERAL PROVISIONS RIGHT OF ENTRY FOR INSPECTIONS MONITORING, TESTING AND CORRECTIVE ACTION |
| Chapter 20-64. UNDERGROUND STORAGE TANKS - DISTRICT OF COLUMBIA UST TRUST FUND, DISTRICT INITIATED CORRECTIVE ACTIONS AND COST RECOVERY |
| Chapter 20-65. UNDERGROUND STORAGE TANKS - LICENSING AND CERTIFICATION OF TANK INSTALLERS, REMOVERS, TESTERS, AND OPERATOR TRAINING REQUIREMENTS |
| Chapter 20-66. UNDERGROUND STORAGE TANKS - ENFORCEMENT PROCEDURES |
| Chapter 20-67. UNDERGROUND STORAGE TANKS - FINANCIAL RESPONSIBILITY |
| Chapter 20-70. UNDERGROUND STORAGE TANKS - DEFINITIONS |
| Chapter 20-72. ENVIRONMENTAL POLICY ACT REGULATIONS |