Salt water is continuing to creep into private wells and some deep aquifers on the Cape May peninsula, forcing some homeowners to consider other sources of drinking water.

Prompting Cape May City to plan a sharp increase in capacity for a plant that desalinates sea water, state and local officials said.

Although salinity levels in about two dozen “sentinel” wells — those designed to provide an early warning of salt water intrusion — are still below limits set by the state Department of Environmental Protection, coastal communities are being urged to consider their options for ensuring that drinking water supplies are sustainable in the long term.