From source to sink
Where London water comes from
A plain-language tour of the lakes, rivers, or wells that feed London, the plants that clean the water, and how it reaches kitchen taps. Lab grades for hardness, lead, and pH live on the water quality page.
On the map
Where London water lives
Source waters and treatment plants pinned from published utility names. Open a pin below for the full OpenStreetMap view.
- CityLondon
Municipal service area
- Source waterLake Huron
Lake Huron supply corridor
- Source waterLake Erie
Source water
- Treatment plantLake Huron Primary Water Supply System Water Treatment Plant
Approximate pin near London (exact plant coordinates pending)
- Treatment plantElgin Area Primary Water Supply System Water Treatment Plant
Approximate pin near London (exact plant coordinates pending)
Map data © OpenStreetMap contributors. Pins are approximate for orientation, not legal survey points.
Deep dive for households
London drinking water starts as surface water (rivers, lakes, or reservoirs). The named sources on the utility record are Lake Huron, Lake Erie. That is the water that eventually reaches kitchen taps after treatment, not a separate bottled brand.
London uses more than one treatment plant (Lake Huron Primary Water Supply System Water Treatment Plant; Elgin Area Primary Water Supply System Water Treatment Plant). Utilities often run plants in parallel so different neighbourhoods can be served, or so one plant can cover for another during maintenance. Lake Huron Primary Water Supply System Water Treatment Plant: Regional plant north of Grand Bend treating Lake Huron water for London and other member municipalities. Board-owned; OCWA-operated; capacity about 340 ML/day. Elgin Area Primary Water Supply System Water Treatment Plant: Regional plant east of Port Stanley treating Lake Erie water. Board-owned; OCWA-operated; capacity about 91 ML/day. Water reaches London via the Elgin-Middlesex Pumping Station.
After treatment, water moves through pumps, storage, and underground mains to reach streets and buildings. City of London owns and operates the local Drinking Water System (Class IV distribution / Class II treatment rating for city assets) with more than 2,100 km of pipes, reservoirs, and pumping stations. Regional boards supply bulk treated water; London is administering municipality for the Lake Huron board.
One detail that makes London water feel local: London is unusual among large Ontario cities in blending two Great Lakes,Huron via Grand Bend and Erie via Port Stanley,into one municipal distribution system. Lab grades for hardness, lead, and pH sit on the city water quality page; this overview is about the route the water travels.
Where it starts
Surface water
Rivers, lakes, or reservoirs, not underground wells as the main draw.
Research confidence: high
Named source waters
- Lake Huron
- Lake Erie
Treatment plants
These are the buildings that filter and disinfect water before it enters city pipes.
Lake Huron Primary Water Supply System Water Treatment Plant
Regional plant north of Grand Bend treating Lake Huron water for London and other member municipalities. Board-owned; OCWA-operated; capacity about 340 ML/day.
Elgin Area Primary Water Supply System Water Treatment Plant
Regional plant east of Port Stanley treating Lake Erie water. Board-owned; OCWA-operated; capacity about 91 ML/day. Water reaches London via the Elgin-Middlesex Pumping Station.
How it reaches your street
City of London owns and operates the local Drinking Water System (Class IV distribution / Class II treatment rating for city assets) with more than 2,100 km of pipes, reservoirs, and pumping stations. Regional boards supply bulk treated water; London is administering municipality for the Lake Huron board.