Water supply wells located over or near the saltwater wedge can draw the saltwater upward, creating a saltwater cone that might reach and contaminate the well.

On the island's east coast, the tsunami contaminated wells on which many villagers relied for drinking water.

A growing number of jurisdictions have outlawed open-loop systems that drain to the surface because these may drain aquifers or contaminate wells.

Cesspits contaminated the wells which many people still used to get their water.

While this made removal of solid waste easier, the seeping liquid waste often contaminated well water sources, creating public health problems.