374Water To Effect 1-For-10 Reverse Stock Split

On December 14, 2025, 374Water Inc. (the "Company"), entered into a letter agreement (the "Agreement") with Mr. Yaacov (Kobe) Nagar.

Pursuant to the Agreement, Ms. Deanna Rene Estes will tender her resignation as a member of the Board of Directors of the Company (the "Board"), which resignation shall be effective following and no later than the date that the inspector of elections for the 2025 Special Meeting of Stockholders of the Company held on December 15, 2025 (the "Special Meeting") certifies that the Company's stockholders approved and adopted by the requisite vote the Reverse Stock Split Proposal as defined in the definitive proxy statement of the Company furnished to stockholders of the Company in connection with the Special Meeting, which was filed with the U.S. Securities and Exchange Commission on November 3, 2025.

Further, pursuant to the Agreement, the Company agreed, among other things, to identify three candidates to be appointed to the Board (the "Candidates"), each of whom shall be mutually acceptable to the Company and Mr. Nagar, among other qualifications. Upon the identification of certain Candidates as provided in the Agreement, each of Messrs. Buddie Joe (BJ) Penn and James Vanderhider have agreed to resign as members of the Board.

The Company also agreed that if the Reverse Stock Split Proposal is approved and adopted by the requisite vote of the Company's stockholders at the Special Meeting, the reverse stock split contemplated by the Reverse Stock Split Proposal will effected at a ratio of 1-for-10 shares.

In addition, pursuant to the Agreement, Mr. Nagar has agreed to abide by certain voting commitments. Specifically, Mr. Nagar has agreed to, or his representatives will, appear in person or by proxy at the Special Meeting and to vote all shares of common stock of the Company beneficially owned in accordance with the Board's recommendations with respect to all proposals submitted to stockholders at the Special Meeting.

The Agreement will remain effective until the earlier of (i) the appointment of the third Candidate contemplated in the Agreement and (ii) the date that is thirty (30) calendar days following written notice of a breach of the Agreement from the non-breaching party, subject to certain conditions as described in the Agreement.