How to Remove Rust from Well Water (What Actually Works)

A caller once told me his water was "rusty." My answer was "Oh, iron." The rust in well water is almost always iron in the water itself, coming up from the well. Tap the picture that looks like your water.

Which one looks like yours? Tap it.

Orange as soon as it pours Clear water, orange stains later Rusty at first, then clear Orange slime in the toilet tank

What the rust in your water is

It is iron. The water underground runs through iron-bearing rock, dissolves the iron and carries it into your well. When that iron hits the air, it turns to rust, and the rust stains whatever the water sits on. Iron starts to stain at 0.3 parts per million. There are two kinds, and a glass of water tells them apart.

Red-water iron comes out orange

If you run the faucet and the water is orange right away, that is red-water iron (ferric iron). The iron has already turned to rust before it reaches your tap, and it stays the same color however long the water runs.

Clear-water iron turns orange later

If you fill a glass and the water is clear, but an hour or two later it turns orange, that is clear-water iron (ferrous iron). It stays dissolved until the air gets to it. That is why it stains the toilet you use most: the water sits in the bowl, the iron turns to rust, and the whole bowl goes a reddish orange.

Orange slime is usually plain iron

When people call me about orange slime in the toilet tank or on their filters, it is usually iron with red clay in it. As I told one caller, "Well, that's iron. That's clay in the water. That's not iron bacteria." Iron bacteria do happen, and the certified well test does not check for them; my iron bacteria guide covers how to tell.

Is it my old pipes or the well?

Typically it's your well water. If the water runs orange at every tap, hot and cold, and keeps running orange, the iron is coming from the well. The house can add some, though. Minnesota's health department says iron "can also result from corrosion of iron or steel well casing or water pipes." These are the signs that point one way or the other.

The first-draw rust is easy to check. As I told one caller, "Now when it sits in the pipes for a while and you first turn it on, it can come out a reddish color, but then it'll clear up." Red-water iron from the well does not clear up; it stays orange.

To be sure, test two samples. North Dakota State's extension service says to draw the sample from a faucet close to the well after running it 15 minutes, and "If your house has metal pipes or a galvanized pressure tank, submit an additional sample from within the house." If the sample from inside has more iron than the one at the well, the house is adding it.

Callers ask me about the pressure tank, too. A caller with 7 ppm of iron asked me whether his tank was making it: "No, no. The well tanks don't do that. It's coming from the well." When you drain an old tank and rusty gunk comes out, that is iron and red clay from the well that settled in the curved bottom. Steel tanks do rust out, though, and the fitting underneath "is usually the thing that rusts out first, especially if you have acidic water."

Low pH is what eats the metal. North Dakota State says water with high acidity "can be corrosive to metal pipes and fixtures." If your test shows a pH under 7, my guide on how to stop copper pipe corrosion covers that fix.

Why well water suddenly turns rusty

Rust in a well that was fine for years can follow a change in the water underground, or work on the well that stirred up sediment. These are the causes I talk callers through.

• The aquifer changed. A Rhode Island caller had 30 years of good water, then 7 feet of snow, then orange tubs and 3 ppm of iron. I told him, "The aquifer changed, and it can change from miles away."
• A new pump was set too deep. A pump close to the bottom of the well pulls sediment and red clay all the time. A well company can pull it up 10 or 20 feet to get it away from the sediment.
• The well was drilled deeper, or it is new. One caller's well was dug deeper and then "turned orange a lot faster." And a new well's iron does not go away: "It actually can get worse as you use more water and pull it from the aquifer."

Shocking the well does not help with iron; that answer is in the questions below.

Get a lab number first

A certified lab test tells you how much iron you have and your pH, the two numbers that decide what goes in. Iron removal works best near pH 8. If yours is lower, send me your test before you order: an acid neutralizer goes in too, and I set its place from your test. Take the sample before any filter or softener, so it shows what is in the well. My guide on how to test for iron in well water walks through reading the report.

No lab report yet? Certified lab test, $199

Test how much iron you have

One certified lab test, mailed to you, run by an accredited lab, reports iron, manganese, pH and hardness. It does not test for tannins or iron bacteria. If you already have a lab report, skip this.

Get the certified well water test

Results usually 2 to 4 weeks after you order.

What removes rust from well water

An air injection iron filter with Katalox Light takes out both kinds of iron, clear-water and red-water, before the water reaches your pipes. The valve keeps an air pocket in the top of the tank. The air turns the dissolved iron into rust, the Katalox Light (the filter media inside the tank) traps it, and on a set schedule the tank backwashes the iron down the drain. There are no chemicals and no cartridges to change.

Every size is rated for 30 ppm of iron, 15 ppm of manganese and 10 ppm of hydrogen sulfide. Above 30 ppm, I put two 2.5 tanks in a row. It treats the whole house, not one faucet, because "You wanna filter all your water so you don't have any orange or iron staining anywhere inside or outside the house." There is no yearly maintenance; the Katalox Light is replaced every 6 to 8 years.

The tank ships empty, with the Katalox Light in separate bags that are loaded at install, and the bypass valve pre-installed on the control valve. Drain tubing is not included. We recommend a licensed plumber, who typically finishes the install in 2 to 3 hours for about $800, and I support your plumber by phone at 800-460-5810.

In the video I give the iron rating as 15 ppm; the rating we use for every size is 30 ppm.

Which size fits your house

The size comes from how many people live in the house, how much iron you have, and how much water your well puts out for the backwash. Most homes buy the 2.5.

Have your water test in hand?

Text me your lab report

Send a photo of the lab report and I'll tell you which size fits, and whether an acid neutralizer or a softener goes in with it.

Text Aidan443-277-2204 Call800-460-5810Aidan

Call 800-460-5810 or text Aidan at 443-277-2204. 8 AM to 5 PM Eastern, seven days a week.

What does not get rust out

A sediment cartridge or a spin-down filter catches rust particles but not dissolved iron. As I tell callers, "Iron's dissolved in water. It's not a sediment." What a cartridge does catch clogs it fast. A 5 micron Big Blue ahead of the treatment still has a job: it keeps sand and dirt out of the valves.

A softener is not the fix either. "Water softeners are not really meant to take out iron. People keep selling them that way, but they're not meant to take out iron and iron shortens the life of the resin." Softeners remove only small amounts of iron. If you have hard water too, the order is well tank, iron filter, then the softener; my guide can a water softener remove iron has the details.

For every method side by side, with what each one costs over 10 years, see how to remove iron from well water.

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