Document and Entity Information	12 Months Ended
	Dec. 31, 2020 shares
Cover [Abstract]
Entity Registrant Name	EURO TECH HOLDINGS CO LTD
Entity Central Index Key	0001026662
Document Type	20-F
Document Period End Date	Dec. 31, 2020
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Is Entity a Well-known Seasoned Issuer?	No
Is Entity a Voluntary Filer?	No
Is Entity's Reporting Status Current?	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	D8
Entity File Number	000-22113
Document Annual Report	true
Document Transition Report	false
Document Shell Company Report	false
Entity Common Stock, Shares Outstanding	3,092,859
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020