Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * Cook Gregory B 2. Issuer Name and Ticker or Trading Symbol ECOLAB INC. [ECL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Co-COO - Global Businesses (Last) (First) (Middle) 1 ECOLAB PLACE 3. Date of Earliest Transaction (Month/Day/Year) 05/04/2026 (Street) ST. PAUL, MN 55102 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 05/04/2026 M 8,396 A (1) 20,069.394 D Common Stock 05/04/2026 F(2) 3,828.576 D $257.925 16,240.818 D Common Stock 3,614.855(3) I By Ecolab Savings Plan

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Restricted Stock Units

(4)

05/04/2026

M

8,396

05/04/2026(1)

05/04/2026(1)

Common Stock

8,396

$ 0

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Cook Gregory B 1 ECOLAB PLACE ST. PAUL, MN 55102			Co-COO - Global Businesses

Signatures

/s/ Corinne Lawson, as Attorney-in-Fact for Gregory B. Cook		05/06/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	On May 4, 2022, the reporting person was granted 8,396 restricted stock units, vesting as to 100% of the units on the fourth anniversary of the date of grant.
(2)	Reflects the reporting person's payment of minimum statutory tax obligations by withholding shares of Ecolab Common Stock incident to the vesting of restricted stock units in accordance with Rule 16b-3.
(3)	Number of UNITS in the Ecolab Stock Fund of the Ecolab Savings Plan (401(k) Plan) as of April 30, 2026. Includes 58.726 UNITS acquired since the reporting person's last report. (The 3,614.855 UNITS are the equivalent of approximately 6,635 shares of the issuer's Common Stock.)
(4)	Restricted stock units convert into common stock on a one-for-one basis.

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