Cover - shares	9 Months Ended
	Sep. 30, 2022	Nov. 01, 2022
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, 2022
Entity Filer Category	Non-accelerated Filer
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2022
Entity Ex Transition Period	false
Entity Common Stock Shares Outstanding		126,680,895
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	000-27866
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	88-0271109
Entity Interactive Data Current	Yes
Entity Address City Or Town	Durham
Entity Address State Or Province	NC
Entity Address Postal Zip Code	27701
Entity Address Address Line 1	701 W Main Street
Entity Address Address Line 2	Suite 410
Security 12b Title	Common Stock, par value $0.0001
Trading Symbol	SCWO
Security Exchange Name	NASDAQ
City Area Code	919
Local Phone Number	888-8194