Well Water Guide: Testing, Common Problems, and Treatment
Roughly 43 million Americans rely on private wells for drinking water. The federal government regulates none of them.
The Safe Drinking Water Act covers public water systems, those serving 25 or more people. Your private well sits outside that framework entirely. No agency tests it, reports violations, or requires treatment. That’s entirely your responsibility.
The Testing You Actually Need
The CDC minimum recommendation is annual testing for:
- Total coliform bacteria (indicates whether surface contamination is reaching the well)
- E. coli (direct indicator of fecal contamination)
- Nitrates
- pH and total dissolved solids
But that’s the bare minimum. A more complete picture also includes:
Iron and manganese. Aesthetic problems (staining, metallic taste) at moderate levels; manganese has documented neurological effects at high levels.
Arsenic. Naturally occurring in bedrock in New England, the Rocky Mountain West, the midwest, and parts of the south. The EPA MCL for arsenic is 10 ppb, but some research suggests health effects at lower levels.
Hardness. Not a health risk, but affects treatment decisions.
Volatile organic compounds (VOCs). Relevant if you’re near industrial sites, dry cleaners, or gas stations.
PFAS. Relevant if you’re near military installations, airports, or industrial manufacturers.
Radon. Occurs in well water in granite-heavy geology. When you use hot water, radon off-gases into the air. New England and the mid-Atlantic have higher rates.
A comprehensive baseline well water test costs $150, $400 depending on the panel. Do it once, then test annually for bacteria and nitrates and repeat the full panel every few years or when anything changes.
The Most Common Problems and Fixes
Coliform bacteria. If you test positive for total coliform, follow up immediately with an E. coli test. E. coli confirms fecal contamination. For ongoing protection, UV disinfection systems kill bacteria without chemicals and are the standard solution for private wells. Shock chlorination is a temporary disinfection step, not a permanent fix.
Nitrates above 10 mg/L. A health risk for formula-fed infants under six months. Boiling does not remove nitrates, it concentrates them. Reverse osmosis removes nitrates effectively. Distillers also work.
Iron above 0.3 mg/L (the aesthetic limit). Causes orange-brown staining in sinks, tubs, and laundry. The form of iron matters: dissolved iron needs an oxidizing filter, iron bacteria need shock chlorination first. See how to remove iron from well water and best iron filters for well water.
Manganese above 0.05 mg/L. Black staining and a documented health advisory for neurological effects. Oxidizing filters handle manganese below 3 mg/L. Higher levels need aeration first.
Arsenic above 10 ppb. RO removes arsenic effectively. So does activated alumina, which is less expensive and handles arsenic specifically without treating the whole water supply.
Hard water. An ion exchange water softener handles it. Very common in well water depending on local geology. Salt-free conditioners don’t actually reduce hardness. See water softener vs. salt-free conditioner for the honest comparison.
Well Maintenance
Beyond testing, basic well maintenance reduces contamination risk:
Keep a six-foot cleared zone around the wellhead, no fertilizer, pesticide, or fuel storage within that radius.
Inspect the well casing annually for cracks, gaps at the top, or signs of surface water entry.
After flooding, pump the well and test before drinking. Floodwater carries surface bacteria directly into the aquifer through improperly sealed casings.
Know where your wellhead is. If contractors or landscapers are working near it, they need to know too.
Getting a Water Test
Best Mail-In Water Tests covers certified labs that handle well water panels. A state-certified lab with NELAP accreditation is the standard to look for.
Your county health department may also offer subsidized or free testing for bacteria and nitrates. Worth calling before paying for a private lab.