Document and Entity Information - shares	6 Months Ended
	Jul. 01, 2018	Jul. 25, 2018
Entity Registrant Name	WATTS WATER TECHNOLOGIES INC
Entity Central Index Key	0000795403
Document Type	10-Q
Document Period End Date	Jul. 01, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q2
Class A
Entity Common Stock, Shares Outstanding		27,804,706
Class B
Entity Common Stock, Shares Outstanding		6,329,290