(a) Discovery shall be conducted according to the Texas Rules of Civil Procedure, unless commission rules provide or the judge orders otherwise. The Texas Rules of Civil Procedure shall be interpreted consistently with this chapter, the Texas Water Code, the Texas Health and Safety Code, and the Texas Administrative Procedure Act. Drafts of prefiled testimony are not discoverable.
(b) Discovery in contested case hearings using prefiled testimony.
  (1) This subsection is applicable to contested case hearings for applications which are subject to the jurisdiction of the State Office of Administrative Hearings (SOAH) under 1 TAC §155.51 (relating to Jurisdiction), except for:
    (A) water ratemaking proceedings; and
    (B) sewer ratemaking proceedings.
  (2) All discovery on a party must be completed before the deadline for that party to submit its prefiled testimony.
  (3) In cases where all parties share the same deadline for submission of prefiled testimony, a single deadline for completion of discovery shall apply to all parties.
  (4) If parties have different deadlines for the submission of prefiled testimony, the deadline to complete discovery on a party shall be no later than the final deadline for that party to submit prefiled testimony. After a party's final deadline to submit its prefiled testimony in a contested case, that party is no longer subject to discovery from other parties in the case.
  (5) The requirements of this subsection do not relieve a party's duty to supplement its discovery responses as required by Texas Rules of Civil Procedure, §193.5 and §195.6.
(c) All other contested case hearings are governed by this section as it existed immediately before the effective date of this section and the rule is continued in effect for that purpose.

Source Note: The provisions of this §80.151 adopted to be effective June 6, 1996, 21 TexReg 4763; amended to be effective May 3, 2012, 37 TexReg 3147; amended to be effective May 14, 2020, 45 TexReg 3087