| Cover | Jul. 31, 2024 |
| Cover [Abstract] | |
| Entity Registrant Name | 374WATER INC. |
| Entity Central Index Key | 0000933972 |
| Document Type | 8-K |
| Amendment Flag | false |
| Entity Emerging Growth Company | false |
| Document Period End Date | Jul. 31, 2024 |
| Entity File Number | 001-41420 |
| 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 | 440 |
| Local Phone Number | 609-9677 |
| Security 12b Title | Common Stock, par value $0.001 |
| Trading Symbol | SCWO |
| Security Exchange Name | NASDAQ |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
