| Document and Entity Information | Nov. 01, 2021 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Nov. 1, 2021 |
| Entity File Number | 001-11499 |
| Entity Registrant Name | WATTS WATER TECHNOLOGIES INC |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 04-2916536 |
| Entity Address, Address Line One | 815 Chestnut Street |
| Entity Address, City or Town | North Andover |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 01845 |
| City Area Code | 978 |
| Local Phone Number | 688-1811 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Class A Common Stock, par value $0.10 per share |
| Trading Symbol | WTS |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000795403 |
| Current Fiscal Year End Date | --12-31 |
| Amendment Flag | false |
