Texas Local Government Code - LOC GOV'T § 43.129. Consensual Annexation

The municipality may annex for limited purposes any land for which the landowner requests annexation and provides to the municipality before the effective date of the annexation the landowner's written consent to annexation for limited purposes. With respect to any larger parcels of property, consent of the owners of at least 51 percent of the total affected territory must be evidenced by appropriate signatures on the limited-purpose annexation request.  A landowner's written consent to limited-purpose annexation is binding on all future owners of land in the area annexed for limited purposes pursuant to the consent.