Groundwater

Groundwater is water stored underground in soil, sand, and rock. Rain and snowmelt seep down to fill these spaces, forming the water table. Wells must reach below the water table to access enough water for daily use.

As groundwater moves through soil and rock, many contaminants are naturally filtered out, making it generally a safe drinking water source. However, groundwater can still be affected by nearby pollution, such as fertilizers, septic systems, or industrial chemicals, so regular testing is important to ensure its safety.

Groundwater Protection & Testing
Groundwater is a valuable resource, but it can be contaminated by sources such as leaking underground tanks, failing septic systems, landfills, fertilizers, pesticides, and spills of oil or chemicals. Once pollution reaches groundwater, it is difficult and costly to clean up—sometimes requiring a new well. The easiest and most effective way to protect groundwater is prevention: properly dispose of household chemicals, use fertilizers carefully, and practice conservation.

Contaminants can appear in drinking water without taste, smell, or color, so regular testing is essential, especially for private well owners. The Department of Health recommends testing at least once a year for coliform bacteria and nitrate. If nitrate levels are 5 mg/L or higher, consider retesting in six months. Testing for arsenic twice—once in summer and once in winter—is also suggested, as seasonal changes may affect levels.