A Practice Note addressing the regulation of oil and gas injection and disposal wells in Texas, including the Safe Drinking Water Act's (SDWA) Underground Injection Control (UIC) provisions, injection and disposal well permitting under Railroad Commission of Texas (RRC) Statewide Rules 9 and 46, injection and disposal permit terms and conditions, and monitoring, reporting, and testing requirements. This Note also describes RRC injection application protests, complaints, and hearings, special requirements for hydrogen sulfide (H₂S) injection wells, and issues posed by induced seismic activity associated with injection and disposal wells.