|(a) Except as provided by subsection (b) of this section, a
certificate of adjudication, permit, certified filing or unadjudicated claim
to appropriate state water is subject to all prior and vested riparian rights
of others using water on the stream or other source of supply.
(b) Except for water rights granted on the mainstem of the
Rio Grande below the Amistad Reservoir (see, generally, Chapter 303 of this
title relating to Operation of the Rio Grande) and certain uses exempt from
permitting under Texas Water Code §§11.142, 11.1421 and 11.1422
(see, generally, Subchapter C of this Chapter), as between appropriators,
first in time is first in right.
(c) The time priority of an appropriation of water dates from
the filing of the related application with the commission or as determined
with a final decree in accordance with Texas Water Code §11.323. The
application is considered filed after the application has been declared administratively
complete in accordance with §281.17 of this title (relating to Notice
of Receipt of Application and Declaration of Administrative Completeness)
and filed with the chief clerk.