Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2012	Jul. 01, 2012	Jan. 31, 2013 Class A Common Stock	Jan. 31, 2013 Class B Common Stock
Entity Registrant Name	WATTS WATER TECHNOLOGIES INC
Entity Central Index Key	0000795403
Document Type	10-K
Document Period End Date	Dec. 31, 2012
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float		$ 924,049,140
Entity Common Stock, Shares Outstanding			28,661,416	6,588,680
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY