The decision to test your water depends on various factors, including your and your family's health. Signs such as taste, color, odor, and staining of clothes or fixtures may indicate water quality issues. Considerations include the proximity of your water well to septic systems and the composition of your home's plumbing materials. This fact sheet offers information to help you determine whether testing your water is necessary, along with suggested tests based on your situation.

• If you suspect lead in your household plumbing or water service lines, testing your water is essential. Most water systems conduct lead tests as part of routine monitoring, providing a system-wide perspective that may not reflect conditions at individual faucets. Testing your home's drinking water is necessary to determine if unsafe lead levels are present. NSF International-certified faucet or pitcher filters can effectively remove lead from drinking water.
• If considering a home water treatment unit, test your water to identify contaminants and make informed decisions before contacting dealers.

Reference: https://www.epa.gov/sites/default/files/2015-11/documents

It is recommended to test your water annually for total coliform bacteria, nitrates, total dissolved solids, and pH levels. This is especially crucial if you have a new well or if there have been replacements or repairs to pipes, pumps, or the well casing.

Reference: https://www.epa.gov/sites/default/files/2015-11/documents

• Recurring gastro-intestinal illness: Coliform bacteria
• Household plumbing or service lines that contain lead: pH, lead, copper
• Radon in indoor air or region is radon rich: Radon
• Corrosion of pipes, plumbing: Corrosion, pH, lead
• Nearby areas of intensive agriculture: Nitrate, nitrite, pesticides, coliform bacteria
• Coal or other mining operations nearby: Metals, pH, corrosion
• Gas drilling operations nearby: Chloride, sodium, barium, strontium
• Dump, junkyard, landfill, factory, gas station or dry-cleaning operation nearby: Volatile organic compounds, total dissolved solids, pH, sulfate, chloride, metals
• Odor of gasoline or fuel oil, and near gas station or buried fuel tanks: Volatile organic compounds
• Objectionable taste or smell: Hydrogen sulfide, corrosion, metals
• Stained plumbing fixtures, laundry: Iron, copper, manganese
• Salty taste and seawater, or a heavily salted roadway nearby: Chloride, total dissolved solids, sodium
• Scaly residues, soaps don’t lather: Hardness
• Rapid wear of water treatment equipment: pH, corrosion
• Water softener needed to treat hardness: Manganese, iron
• Water appears cloudy, frothy, or colored: Color, detergents

Reference: https://www.epa.gov/privatewells/protect-your-homes-water

Environmental Protection Agency