SCWO · 374Water Inc.

The stock option was granted pursuant to the 374Water Inc. 2021 Equity Incentive Plan, as amended. The option vests as follows: 25% (37,500 shares) on the grant date (July 1, 2026), and the remaining 75% (112,500 shares) in 12 equal quarterly installments of 9,375 shares commencing October 1, 2026 (subject to a rounding adjustment on the final installment). The exercise price equals the closing price of the Issuer's common stock on the Nasdaq Capital Market on the date of grant.

The restricted stock unit award was granted pursuant to the 374Water Inc. 2021 Equity Incentive Plan, as amended. The RSUs vest as follows: 25% (31,250 shares) on the grant date (July 1, 2026), and the remaining 75% (93,750 shares) in 12 equal quarterly installments of 7,813 shares commencing October 1, 2026 (subject to a rounding adjustment on the final installment to account for the aggregate total of 93,750 shares).

This transaction was executed in multiple trades at prices ranging from $0.420 to $0.5229 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

This transaction was executed in multiple trades at prices ranging from $0.4208 to $0.4211 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

This transaction was executed in multiple trades at prices ranging from $0.4207 to $0.4210 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

This transaction was executed in multiple trades at prices ranging from $0.420 to $0.4208 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

This transaction was executed in multiple trades at prices ranging from $0.4202 to $0.4211 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

This transaction was executed in multiple trades at prices ranging from $0.4200 to $0.4383 The price set forth above reflects the weighted-average price per share.

This transaction was executed in multiple trades at prices ranging from $0.5108 to $0.5140 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

This transaction was executed in multiple trades at prices ranging from $0.5103 to $0.5202 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

This transaction was executed in multiple trades at prices ranging from $0.5092 to $0.5231 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

Represents stock options granted to the Reporting Person as a special retention incentive award in connection with his continued service as Chief Operating Officer of 374Water Inc. (the "Company"). 50% of the stock options vest and become exercisable on the first anniversary of the grant date and the remaining 50% of the stock options vest and become exercisable on the second anniversary of the grant date, subject to the Reporting Person's continuous service through each vesting date. In the event of an involuntary termination of the Reporting Person without cause, all remaining unvested stock options will vest and become exercisable immediately. Upon vesting, each stock option gives the Reporting Person the right to purchase one share of the Company's Common Stock at the exercise price. The stock options expire on the date which is ten years from the grant date, unless earlier terminated in accordance with the stock option grant agreement.

Represents stock options granted to the Reporting Person as a special retention incentive award in connection with his continued service as Chief Technology Officer of 374Water Inc. (the "Company"). 50% of the stock options vest and become exercisable on the first anniversary of the grant date and the remaining 50% of the stock options vest and become exercisable on the second anniversary of the grant date, subject to the Reporting Person's continuous service through each vesting date. In the event of an involuntary termination of the Reporting Person without cause, all remaining unvested stock options will vest and become exercisable immediately. Upon vesting, each stock option gives the Reporting Person the right to purchase one share of the Company's Common Stock at the exercise price. The stock options expire on the date which is ten years from the grant date, unless earlier terminated in accordance with the stock option grant agreement.

. Represents stock options granted to the Reporting Person as a special retention incentive award in connection with his continued service as Chief Financial Officer of 374Water Inc. (the "Company"). 50% of the stock options vest and become exercisable on the first anniversary of the grant date and the remaining 50% of the stock options vest and become exercisable on the second anniversary of the grant date, subject to the Reporting Person's continuous service through each vesting date. In the event of an involuntary termination of the Reporting Person without cause, all remaining unvested stock options will vest and become exercisable immediately. Upon vesting, each stock option gives the Reporting Person the right to purchase one share of the Company's Common Stock at the exercise price. The stock options expire on the date which is ten years from the grant date, unless earlier terminated in accordance with the stock option grant agreement.

This transaction was executed in multiple trades at prices ranging from $0.4500 to $0.4891 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

Represents stock options granted to the Reporting Person as compensation in connection with his appointment as Interim Chief Executive Officer of 374Water Inc. (the "Company"). The vesting commencement date of the stock options is October 7, 2025. 25% of the stock options vest and become exercisable on the vesting commencement date, 25% of the stock options vest and become exercisable 90 days after the vesting commencement date, 25% of the stock options vest and become exercisable 180 days after the vesting commencement date and 25% of the stock options vest and become exercisable 270 days after the vesting commencement date, subject to the Reporting Person's continuing service through each vesting date. (Continues in footnote no. 2)

Notwithstanding the foregoing, the stock options will vest and become exercisable immediately in the event of (i) a change of control of the Company, (ii) the hiring of a full-time Chief Executive Officer for the Company, or (iii) the termination of the Reporting Person other than for cause. Upon vesting, each stock option gives the Reporting Person the right to purchase one share of the Company's Common Stock at the exercise price. The stock options expire on the date which is ten years from the date on which the applicable shares vest, unless earlier terminated in accordance with the stock option grant agreement.

This transaction was executed in multiple trades at prices ranging from $0.3901 to $0.4127 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

This transaction was executed in multiple trades at prices ranging from $0.3900 to $0.3999 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

100% of the shares vest on August 28, 2026, subject to the Reporting Person's continuous service through such date

The restricted stock unit vests in equal monthly installments over 36 months, on the last day of each month, beginning on March 31, 2025, subject to the Reporting Person's continuous service through each vesting date.

The restricted stock unit vests in equal monthly installments over 36 months, on the last day of each month, beginning on March 31, 2025, subject to the Reporting Person's continuous service through each vesting date

The shares subject to the Restricted Stock Unit vest in equal increments on the last day of every month over 36 months, beginning on March 31, 2025, subject to the Reporting Person's continued employment with the Issuer on each vesting date.

100% of the shares vest on August 28, 2026, subject to the Reporting Person's continuous service through such date.

Fully vested on date of grant.

100% of the shares vest on August 28, 2026, subject to the Reporting Person's continuous service through such date.

Fully vested on date of grant.

100% of the shares vest on August 28, 2026.subject to the Reporting Person's continuous service through such date.

Fully vested on date of grant.

100% of the shares vest on August 28, 2026, subject to the Reporting Person's continuous service through such date.

The restricted stock unit vests in equal monthly installments over 36 months, on the last day of each month, beginning on March 31, 2025, subject to the Reporting Person's continuous service through each vesting date.

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.2849 to $0.2903, inclusive. The reporting person undertakes to provide to 374Water Inc., any security holder of 374Water Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in footnote (1) to this Form 4.

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.2541 to $0.2640, inclusive. The reporting person undertakes to provide to 374Water Inc., any security holder of 374Water Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in footnote (1) to this Form 4.

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.2450 to $0.2519, inclusive. The reporting person undertakes to provide to 374Water Inc., any security holder of 374Water Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in footnote (2) to this Form 4.

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.2444 to $0.2493, inclusive. The reporting person undertakes to provide to 374Water Inc., any security holder of 374Water Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in footnote (1) to this Form 4.

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.2368 to $0.2416, inclusive. The reporting person undertakes to provide to 374Water Inc., any security holder of 374Water Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in footnote (1) to this Form 4.

This transaction was executed in multiple trades at prices ranging from $0.4200 to $0.4202 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

This Form 4 amends the Form 4 filed on 6/18/2025 to correct the amount of common stock sold. The number of common stock sold was inadvertently reported as 57,650 shares; the correct amount of common stock sold was 51,598.

This transaction was executed in multiple trades at prices ranging from $0.400 to $0.402 The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

This transaction was executed in multiple trades at prices ranging from $0.400 to $0.403. The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.