Cover - shares	9 Months Ended
	Sep. 30, 2023	Nov. 09, 2023
Cover [Abstract]
Entity Registrant Name	374WATER INC.
Entity Central Index Key	0000933972
Document Type	10-Q
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Small Business	true
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Current Reporting Status	Yes
Document Period End Date	Sep. 30, 2023
Entity Filer Category	Non-accelerated Filer
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2023
Entity Ex Transition Period	false
Entity Common Stock Shares Outstanding		132,667,107
Entity File Number	000-27866
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	88-0271109
Entity Address Address Line 1	701 W Main Street
Entity Address Address Line 2	Suite 410
Entity Address City Or Town	Durham
Entity Address State Or Province	NC
Entity Address Postal Zip Code	27701
City Area Code	919
Local Phone Number	888-8194
Security 12b Title	Common Stock, par value $0.0001
Trading Symbol	SCWO
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes