Water Affordability, Transparency, Equity, and Reliability Act of 2025

Amends section 1465 of the Safe Drinking Water Act: (a) replaces the phrase 'fountains manufactured prior to 1988' with 'infrastructure'; (b) replaces subsection (b) to specify allowable uses of grant funds (installing/repairing/replacing infrastructure to ensure school drinking water fountains, coolers, and bottle filling stations are lead free; monitoring and reporting of lead levels as determined appropriate by the Administrator); (d) strikes '$5,000,000' and inserts 'inserting,050,000,000' (text as shown).

Amends the first sentence of 42 U.S.C. 300j–12(i)(1) by striking '1½' and inserting 'Three', and by striking 'may' and inserting 'shall'.

Amends paragraph (2) to change wording about the timing and availability of funds, specifying 'were made to the State with funds made available for fiscal year 2021.'

Adds a new paragraph (13) to the list of projects and activities eligible for assistance, and makes minor punctuation edits to existing subparagraphs (11)(B) and (12)(B). The new paragraph authorizes assistance to municipalities or intermunicipal, interstate, or State agencies for purchasing a privately owned treatment works and for expenses related to canceling a contract for operation or management of a publicly owned treatment works.

Rewrites subparagraph (B) to set the additional limitation: a State may use not less than 50 percent of the total amount received by the State in capitalization grants under this title for a fiscal year for providing additional subsidization under this subsection.

Revises subsection (d) authorization of appropriations by replacing the prior fiscal-year-limited authorization with a new per-fiscal-year authorization.

Adds a new section 9512 to chapter 98 of the Internal Revenue Code establishing the Water Affordability, Transparency, Equity, and Reliability Trust Fund in the Treasury; authorizes transfers to the Trust Fund equal to estimated increases in Federal revenues attributable to the corporate tax amendment, sets an annual cap on transfers (larger of $35,000,000,000 or one-twentieth of specified 20-year needs), and makes amounts in the Trust Fund available without further appropriation and without fiscal year limitation.

Amends 26 U.S.C. §11(b) by striking the existing text of subsection (b) and inserting new text to change the corporate tax rate (text of the new rate is not provided in the section text supplied).