Common Tap Water Contaminants

Understanding Tap Water

Municipal water is treated and tested, but "safe" doesn't mean "pure." Contaminants can come from the source, treatment process, or pipes between the plant and your tap. Here are the most common concerns.

Chlorine & Chloramine

Added intentionally to kill bacteria. Chlorine is the most common cause of bad-tasting tap water.

• Health effects: Generally safe at municipal levels, but linked to some health concerns at high exposure
• Other issues: Dry skin, hair damage, bad taste and smell
• Removal: Any carbon filter removes chlorine easily

Lead

Doesn't come from the water supply—it leaches from old pipes and fixtures. Homes built before 1986 are at higher risk.

• Health effects: Serious, especially for children. No safe level. Affects brain development, kidneys, cardiovascular system
• Removal: Quality carbon filters (NSF 53 certified), RO systems

More about lead in water →

PFAS (Forever Chemicals)

Industrial chemicals that don't break down. Found in thousands of water supplies. Used in non-stick coatings, firefighting foam, and many products.

• Health effects: Linked to cancer, thyroid disease, immune problems, developmental issues
• Removal: RO, activated carbon (but not all carbon filters—check certifications), ion exchange

Bacteria & Parasites

Rare in municipal water (chlorine kills them) but common in well water. Includes E. coli, coliform, Giardia, Cryptosporidium.

• Health effects: Gastrointestinal illness, serious illness in immunocompromised
• Removal: UV treatment, RO, filters rated for cysts (1 micron or less)

Nitrates

From agricultural runoff and septic systems. Common in rural well water.

• Health effects: Dangerous for infants ("blue baby syndrome"), may be carcinogenic
• Removal: RO, ion exchange, distillation

Fluoride

Added to most municipal water for dental health. Controversial—some prefer to remove it.

• Health effects: Dental benefits at low levels; concerns about thyroid, brain at higher levels
• Removal: RO, activated alumina, bone char. Most carbon filters do NOT remove fluoride

More about fluoride →

Hard Water Minerals

Calcium and magnesium. Not harmful—actually beneficial for health—but cause scale buildup.

• Effects: Scale on fixtures, spots on dishes, soap scum, reduced appliance life
• Removal: Water softener (not a filter)

More about hard water →

Other Contaminants

• Pharmaceuticals: Trace amounts of medications. Removed by RO, advanced carbon
• Microplastics: Increasingly common. Removed by RO, fine mechanical filtration
• Arsenic: Natural in some groundwater. Removed by RO, specialized media
• Radon: Radioactive gas in some well water. Removed by aeration or GAC