Iron Filters for Well Water: The Complete Guide

If your toilet bowl is turning orange, your laundry is coming out a reddish brown, or a lab report just came back with iron on it, this page is the whole job from start to finish. Find out which kind of iron you have, test for the few things that change the answer, pick the fix that fits your water, put it in the right place in the line, size it to your house and your well, and know what it costs to own. Each step has its own guide, linked where it comes up.

What kind of iron is in your water

The fix depends on which kind of iron is in your water and on the rest of your water test. In the video I put the most common kind this way: "There's clear water iron that you can't see and usually oxidizes over a couple of days after say sits in your toilet tank for a while or your toilet bowl."

Clear-water and red-water iron both come out in the same air-injection filter; as I say in the video, ours "has no issues treating red water iron." Organic iron is harder: the Minnesota Department of Health says tannins can keep iron filters from working well. Black stains instead of orange ones are manganese, which often comes along with iron, and the same filter takes out both (see iron and manganese in well water). The longer version of each kind, with how to tell them apart in a glass, is in types of iron in well water. For the slime itself and shocking the well, see iron bacteria; for yellow water, tannins in well water; for getting the stains off the toilet and the laundry, iron stains.

Test before you buy anything

Get a lab test before you buy an iron filter, because the iron number alone does not pick the system. As I say in the video, "there's multiple things you need to test for other than the iron. You need to test the pH level, you need to test for manganese, you need to test for hardness in the water."

Our $199 well water test reports iron, manganese, hardness and pH from one sample, out of 53 results. The rotten egg gas escapes from an ordinary sample bottle, so the $139 hydrogen sulfide test preserves the sample when you take it. The EPA's 0.3 mg/L for iron is a secondary standard, set for color, staining and taste rather than health; what higher levels mean for your health is in is iron in well water dangerous. How to take the sample and read the iron line is in how to test for iron in well water.

When someone calls me with a report in hand, my first two questions are the ones I asked a caller in September who had 3 ppm of iron: "what's the hardness level and how many people live in the home?"

No lab report yet? Certified lab test, $199

One lab sample covers the whole list

One certified lab test, mailed to you, run by an accredited lab, gives you the numbers this page keys off. If you already have a lab report, skip this.

Get the certified well water test

Which fix fits your water

With iron up to 30 ppm, one iron filter does the job. Every size of our air-injection filter with Katalox Light is rated to remove up to 30 ppm iron, 15 ppm manganese and 10 ppm hydrogen sulfide in one tank.

One buyer with that kind of well wrote, "I have well water with over 20 ppm ferrous and 7 ppm of ferric iron, along with manganese and some sulfur. I was rejected by local water companies saying they could not help me with my high iron issues." She put in two tanks, and later wrote, "now the tanks reduced the iron to literally zero!"

A softener is not the fix for iron. As I put it in the video, "Iron has an adverse effect on resin, the resin beads, the filter media inside a water softener. It actually will shorten the life of the resin over a period of time." A cartridge filter on the wall does no better: "all that's going to do is clog over time and cut off the water pressure in your house." The five ways people try to get iron out, with what each costs over ten years, are compared in how to remove iron from well water.

Sometimes the right answer is less equipment. A caller in August had 1.42 ppm iron, water a little acidic and eating his copper, and a softener that was already taking out a great deal of the iron. I told him, "all you really need to do is put in the backwashing neutralizer ... before the softener, and that should take care of those issues."

What is inside the tank matters as much as the tank. Clack says Birm needs oxygen already in the water and a pH of 6.8 or higher, Inversand says GreensandPlus usually runs with a chlorine feed ahead of it, and Vibrantz says Pyrolox weighs 120 lb a cubic foot; Watch Water says Katalox Light needs no chemical feed. Each maker's numbers, side by side, are in iron filter media compared. Brand names work the same way: in the video I said of names like Iron Breaker and Iron Curtain, "they're just putting a name on it. A lot of times they're using Birm filter, Filox, Pyrolox, or manganese greensand." What is inside one of them is in Iron Curtain vs Katalox Light.

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Send the report and how many people live in the house. Aidan will tell you which of these fits your water, and what size.

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How iron filtration works

Air at the top of the tank makes the dissolved iron solid, and the Katalox Light below catches it. Both steps happen inside one tank. In the video I describe it this way: "the valve pulls in air through a venturi nozzle and creates an air pocket in the top of the tank. And what that air pocket does is it will precipitate the iron out before it even reaches the Katalox Light media. So it's almost like having two filters in one." There is no compressor and no chemical to add.

It ships set to backwash every day, and it can be set to run less often. Each backwash rinses the trapped iron down the drain and refills the air pocket, and it uses about 70 gallons of water on the 1.5 and about 140 on the 2.0 and 2.5. The full cycle, step by step, is in how an iron filter works, and what the backwash water means for a septic system is in backwash water and septic.

That video went up in March, and four things have changed since. The 2.5 is $2,495 today, not the $2,195 I say on camera. Orders now ship with the Fleck 2510 AiQ, the new version of the valve you see. For iron bacteria I now usually recommend this filter with a UV light after it. And I no longer put the iron filter ahead of an acid neutralizer as a rule: I set that order from your test.

Where the iron filter goes in the line

The iron filter goes after the pressure tank and a 5 micron sediment filter, and before the softener. That way the softener gets water with the iron already out. I told that September caller, whose water was also hard, "The iron filter would go first to remove all the iron, and then the ... water softener would go second to remove all the ... hardness from the water."

1. Pressure tank
2. 5 micron sediment filter (a Big Blue)
3. Iron filter
4. Softener, if the water is hard
5. Carbon filter, if you want one for taste
6. UV light, last

If your pH is low, an acid neutralizer goes in too, and I set its place from your test. Why each piece goes where it does is in the correct order for well water treatment systems.

What size iron filter you need

Size the filter by how many people live in the house, how much water your well can give it to backwash, and your iron level. Every size carries the same 30 ppm rating, so the 3.5 is not the high-iron size.

A weak well does not rule out the bigger tank. As I say in the video, "If you don't have enough flow to backwash it correctly, you're going to have to backwash it longer. Instead of the standard 14 minutes, you might have to backwash it for 20 to 25 minutes." The longer sizing walk-through is in the iron filter sizing guide.

Who installs an iron filter

I recommend having a plumber do the install, and I'm a phone call away for your plumber. If you'd rather do it yourself, text me with any questions. Plumbing it in is an inlet and an outlet. The part that takes planning is the drain line, run to a floor drain, standpipe or utility sink with an air gap and sized for the backwash flow, plus an electrical outlet for the valve. A plumber takes about 2 to 3 hours and charges about $800.

What ships: the Vortech mineral tank (empty), the Fleck 2510 AiQ control valve with its stainless bypass valve, a fill funnel, and the Katalox Light, which ships separately and is loaded into the tank at install through the funnel. Drain tubing is not included.

A 1.5 buyer wrote in September that they "installed on our own" and "have had amazing water." A 2.5 buyer was honest about the time: "easy install but took two days not a couple hours like some folks claim." An iron filter and a softener together is a bigger job, about 3 to 4 hours for a plumber, and the two clocks get set about 2 hours apart so they do not backwash at the same time. The steps, with photos of the valve that ships now, are in how to install an iron filter.

What an iron filter costs to own

Owning one costs the filter, a plumber if you use one, and new filter material every 6 to 8 years. There is no salt and no chemical to buy.

For a sense of what the same problem costs elsewhere, one buyer wrote, "Culligan tried to sell me a softener and an acid neutralizer for $10k. This was a much more affordable set up and with out all the maintenance of a softener." The full price breakdown is in iron filter cost.

Iron filter upkeep over the years

Every 6 to 8 years you replace the Katalox Light, and there is no other yearly upkeep. In the video I put it this way: "There's no annual maintenance. About every 6 to 8 years, you're going to take the tank outside, dump it out, completely clean the old Katalox Light media out, and rebed it with new Katalox Light media and put it back into operation for another 6 to 8 years." The tank itself "could last 40 or 50 years, the valve 10 to 15 years before it might need some minor maintenance."

What a media change involves is in replacing Katalox Light, and the rest of the upkeep is in iron filter maintenance.

What owners wrote about their iron filter

These are verified purchases from our reviews, newest first.

Frequently asked questions