Island homes drink groundwater. Every figure here is the Province of British Columbia's own — from its aquifer mapping and its GWELLS well registry — shown verbatim and linked to source. The Province maps 3 aquifers beneath Hornby Island's 1,185 land lots, carrying 725 registered wells, 30 of them with provincial water-chemistry data, and 3 provincial observation wells recording long-term water levels.
Bedrock — Fractured sedimentary rock; 18.8 km²; mapped 2020. Beneath 732 of Hornby Island's lots.
Vulnerability Moderate; productivity Moderate; demand High; quality concern Local.
499 wells on record; 7 water licences; 10 artesian; 16 wells with provincial water-chemistry data; 1 provincial observation well (#288 Active).
Bedrock — Fractured sedimentary rock; 3.8 km²; mapped 2020. Beneath 278 of Hornby Island's lots.
Vulnerability Moderate; productivity Low; demand High; quality concern Regional.
137 wells on record; 2 artesian; 10 wells with provincial water-chemistry data; 1 provincial observation well (#323 Inactive).
Bedrock — Fractured sedimentary rock; 5.2 km²; mapped 2020. Beneath 135 of Hornby Island's lots.
Vulnerability Moderate; productivity Low; demand High; quality concern Local.
89 wells on record; 2 water licences; 2 artesian; 4 wells with provincial water-chemistry data; 1 provincial observation well (#324 Inactive).
The Province classifies each mapped aquifer's intrinsic vulnerability — how easily contamination at the surface could reach the water — as Low, Moderate or High, based on factors like depth to water and what covers the aquifer. A High rating means relatively little natural protection between the surface and the water people draw from. It describes susceptibility, not current contamination. Productivity describes how readily the aquifer yields water; demand describes the level of use. These are the Province's classifications, not ours.
Most Gulf and Northern Gulf island aquifers are fractured rock: water sits in cracks in sedimentary or crystalline bedrock rather than in a porous bed of sand and gravel. Fractured-rock aquifers store comparatively little water and move it unevenly, which is why neighbouring wells on the same island can report very different yields, and why the Province rates most of these aquifers Low productivity.
Aquifer boundaries are a toggleable layer on the island map. This page presents provincial data with explanatory context; it makes no claims about individual wells or properties.