| Name | Location | County | Country | Power source | Type | Function | River |
| Grove Mill, Watford | Watford | Hertfordshire | United Kingdom | Water | Watermill | Corn mill | Gade |
| Hamper Mill, Watford | Watford | Hertfordshire | United Kingdom | Water | Watermill | Paper mill | Colne |
| Old Mill, Cassiobury Park | Watford | Hertfordshire | United Kingdom | Water | Watermill | Pumping mill/wheel | Gade |