The water comes out of the hand pump clear. An hour later it turns yellow or orange in the bucket. Clothes get stained, rice turns dark and tea tastes of metal. This is iron, and it is the most common complaint about borewell water in eastern and north-eastern India.
Iron in water is rarely dangerous on its own. The real problem is what people do next. They stop using the hand pump and go back to open wells or ponds, which carry germs. Removing the iron keeps people on the safe source.
Why the water changes colour
Underground, the iron is dissolved and you cannot see it. When the water meets air, the iron turns into rust and the water goes yellow. Every iron filter uses this. It lets the iron turn into rust on purpose, then catches the rust before you drink the water.
Which filter fits your need
- For one home. A 15 litre steel home filter brings iron down to the safe limit for 4 to 5 paise a litre. One model removes arsenic too.
- For one home, with almost no running cost. A baked clay filter removes 90 to 95% of iron and almost all the mud. One filter lasts about 3 years.
- For a village hand pump. An iron removal plant on the hand pump gives 800 litres an hour. That is enough for about 250 people, with no power and no chemicals.
- For a school, hostel or small town. A large iron filter gives 3,000 to 3,500 litres an hour for under 2 paise a litre.
Check for mud and arsenic too
In the monsoon, the water may also turn muddy. A cheap filter for muddy water makes it clear again. In the Ganga plains, iron often comes with arsenic. If your test shows arsenic, choose a plant that removes both. An iron filter alone does not reliably remove arsenic.
Keep it working
Iron plants usually stop working for one reason: nobody cleans them. Pick a plant with a simple backwash. Train two people in the village to do it, and fix one day each week. This one habit decides whether the plant lasts two months or ten years.
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Request a consultationFrequently asked questions
Is iron in water harmful?
At the levels found in most borewells, iron mainly spoils taste and colour and stains things. The bigger risk is that people switch to dirty water sources.
Can a water softener remove iron?
Only a little. Iron also clogs the softener. If iron is above about 1 mg/L, use an iron filter before the softener.
How often should an iron plant be cleaned?
Usually once or twice a week for a village plant. If the clean water starts turning yellow, it is time to clean.
Sources: Bureau of Indian Standards, IS 10500. The results above come from real use of each method. Your results depend on your water, so test it first.
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