Iron in Drinking Water
EPA limits, health effects, and what to do if your water is affected.
🩨 Health Effects
Iron has no federal primary health-based MCL but is regulated under secondary standards for aesthetics. High iron gives water a metallic taste, rusty or orange-brown color, and stains laundry and fixtures. Elevated iron can encourage bacterial growth in distribution pipes.
📍 Sources in Water
Iron occurs naturally and is very common in groundwater, especially in regions with iron-bearing rock or soil. It also enters water from corrosion of iron and steel pipes in distribution systems and home plumbing.
✅ What To Do
An iron filter (oxidizing or greensand filter), water softener, or whole-house sediment filter can help reduce iron. If you see rust-colored water suddenly, contact your water utility, as this may indicate pipe damage.
📜 Regulation History
Iron has a secondary MCL of 0.3 mg/L (300 ppb), set by the EPA for aesthetic reasons (taste, color, staining) rather than health effects. Secondary standards are non-enforceable guidelines. The WHO does not establish a health-based guideline for iron but notes that taste becomes objectionable above 0.3 mg/L.
🔬 How To Test Your Water
Iron is one of the easiest contaminants to detect visually: rusty-orange staining, metallic taste, or reddish sediment. Home test kits for iron cost $10-$20 and are widely available. Lab tests cost $15-$25. Test for both ferrous (dissolved/clear water) and ferric (particulate/rusty) iron to choose the right treatment.
💧 Which Filters Remove Iron?
Oxidizing filters (birm, greensand, or air injection) are the best whole-house treatment for iron. Water softeners remove low levels of ferrous iron. Sediment filters catch ferric (particulate) iron. For drinking water, NSF/ANSI 53-certified carbon block filters or reverse osmosis systems also reduce iron.
Check your tap water for Iron
Search your ZIP code to see if your water system has had Iron violations, plus lead testing results and an overall safety grade.
Search your ZIP code →Data from the EPA's Safe Drinking Water Information System (SDWIS). MCLs reflect minimum federal standards; some contaminants may pose health risks below these thresholds.