Excessive iron and rust in tap water can stain fixtures and laundry, and also give tap water a rusty tinge and metallic taste. The EPA limit for iron in our water is 0.3 mg/l (0.3 ppm), while natural waters may contain as much as 10 ppm or slightly more iron. Public water supplies keep dissolved iron below 0.2 ppm, so if you have excess iron, you either have a well or seriously corroded iron pipes. Follow these steps to remove excess iron and rust particles from your tap water.
Get your tap water tested to find out the iron content and pH. Many local health departments will test water for a nominal fee. Swimming pool or water treatment supply stores also offer analytical services for tap water. If possible, have the water analyzed for iron, manganese, sulfide, pH and oxygen content.
Choose a filter system with chlorination and a mechanical filter if you have visible rust particles, or water with more than 10 ppm dissolved iron. These systems typically have a chlorination tank and a cartridge filter, a bag filter or a sand filter. Cartridge and bag filters need periodic replacement, while sand filters require backflushing.
Install a water softener system if your water has a pH of 6.8 or less and 0.3 to 10 ppm dissolved iron and moderate to low dissolved oxygen. Water softeners remove calcium and manganese as well as iron, and increase sodium content by ion exchange. Most water softeners require periodic backflushing and replacement of salt which is used in regenerating the ion-exchange resin.
Choose an oxidizing filter if your tap water has a pH above 6.8 and 0.3 to 10 ppm dissolved iron. Oxidizing filters have a medium that oxidizes iron and adsorbs iron particles on the surface of the medium. Greensand filters remove iron, manganese and some hydrogen sulfide (rotten egg odor), and require backflushing and occasional regeneration. Pyrolite medium filters need only periodic backflushing (see Resources below).