Exhibit 5.1

September 8, 2025	811 Main Street, Suite 3700 Houston, TX 77002 Tel: +1.713.546.5400 Fax: +1.713.546.5401 www.lw.com FIRM / AFFILIATE OFFICES
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WaterBridge Infrastructure LLC
5555 San Felipe Street, Suite 1200
Houston, Texas 77056

Re: Initial Public Offering of Class A Shares of WaterBridge Infrastructure LLC

To the addressee set forth above:

We have acted as special counsel to WaterBridge Infrastructure LLC, a Delaware limited liability company (the “Company”), in connection with the proposed issuance of up to 31,050,000 Class A shares representing limited liability company interests in the Company (the “Class A Shares”). The Shares are included in a registration statement on Form S-1 under the Securities Act of 1933, as amended (the “Act”), initially filed with the Securities and Exchange Commission (the “Commission”) on August 22, 2025 (Registration No. 333-289823) (as amended, the “Registration Statement”). The term “Class A Shares” shall include any additional Class A shares representing limited liability company interests in the Company registered by the Company pursuant to Rule 462(b) under the Act in connection with the offering contemplated by the Registration Statement. This opinion is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Act, and no opinion is expressed herein as to any matter pertaining to the contents of the Registration Statement or related prospectus, other than as expressly stated herein with respect to the issuance of the Class A Shares.

As such counsel, we have examined such matters of fact and questions of law as we have considered appropriate for purposes of this letter. With your consent, we have relied upon certificates and other assurances of officers of the Company and others as to factual matters without having independently verified such factual matters. We are opining herein as to the Delaware Limited Liability Company Act (the “Delaware LLC Act”), and we express no opinion with respect to any other laws.

Subject to the foregoing and the other matters set forth herein, it is our opinion that, as of the date hereof, when the Class A Shares shall have been issued by the Company against payment therefor in the circumstances contemplated by the form of underwriting agreement most recently filed as an exhibit to the Registration Statement and have been duly registered on the books of the transfer agent and registrar therefor in the name or on behalf of the purchasers, the Class A Shares will be validly issued and, under the Delaware LLC Act, purchasers of the Class A Shares will

September 8, 2025

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have no obligation to make further payments for their purchase of the Class A Shares or contributions to the Company solely by reason of their ownership of the Class A Shares or their status as members of the Company, and no personal liability for the obligations of the Company solely by reason of being members of the Company.

This opinion is for your benefit in connection with the Registration Statement and may be relied upon by you and by persons entitled to rely upon it pursuant to the applicable provisions of the Act. We consent to your filing this opinion as an exhibit to the Registration Statement and to the reference to our firm in the prospectus under the heading “Legal Matters.” We further consent to the incorporation by reference of this letter and consent into any registration statement filed pursuant to Rule 462(b) with respect to the Class A Shares. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission thereunder.

Sincerely,

/s/ Latham & Watkins LLP