How to Test for Iron in Well Water (And Read Your Results)

Iron starts to stain at 0.3 mg/L, which is the same as 0.3 ppm. Under that, it usually doesn't stain. Over it, you get orange stains in the toilet, the tub and the laundry, and the higher the number goes, the worse it gets. To fix it, I need the exact number, and that comes from a lab.

One warning before you read your report: "<2" does not mean you have no iron. It means under 2, and iron stains at 0.3. About one well in six that my customers send to the lab comes back over 0.3.

Are iron test strips accurate?

A hardware-store strip can show you iron is there. It won't give you the exact number a filter is sized from. People ask me if the test kits from Lowe's or Home Depot are accurate. They're not bad, but they don't give you an exact number. They give you a color to match on a chart.

That chart moves in steps. A common iron strip reads 0, 0.15, 0.3, 0.6, 1, 2 and 5 ppm, so if your water is really 3.2, the most it can tell you is "somewhere between 2 and 5." Some strips only read dissolved iron: the SenSafe strip's own sheet says it "detects dissolved Iron (Fe+2)," which is the clear water kind. And strips can miss it. One customer wrote in that his 21-in-1 strips "looked normal," then a phenanthroline packet "turned an orange color after a minute or so."

A certified lab gives you the number. Our $199 well water test goes to an independent, ISO/IEC 17025-accredited lab in SimpleLab's network and reports iron along with 52 other contaminants and water-chemistry values, including manganese, pH, hardness and coliform bacteria. It usually takes 2 to 4 weeks from order to results. A local lab that comes out and takes the sample is extremely accurate too, and a complete test usually runs a few hundred dollars.

In the video I say the results come in about 5 days. That is the lab's part, once it has your sample. From the day you order to the day you have results is usually 2 to 4 weeks.

What your iron number means

Iron starts to stain at 0.3 mg/L. The higher the number, the worse the staining. People ask me why the EPA has a number for iron if it's not dangerous to drink. Because at 0.3 and above, iron starts to stain. The EPA's 0.3 is a secondary standard, set for "rusty color; sediment; metallic taste; reddish or orange staining," and the EPA says these contaminants "are not considered to present a risk to human health at the SMCL." Is iron in well water dangerous covers the health side.

Those are the first lab reports of 326 customers on private wells, from May 20 to September 29. At 1 part per million and above you'll get that metallic smell, and it tastes like a nosebleed. Over 0.3, what fixes it depends on the number, your pH and your hardness, so I size it from the whole report. How to remove iron from well water compares the methods. The iron filters we sell are rated for up to 30 ppm; over 30, I put two 2.5 tanks in a row.

Already have an iron number?

Text me your water test report

Send a photo of the whole report, not just the iron line, and I'll tell you what your numbers mean for your house.

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

8 AM to 5 PM Eastern, seven days a week. A real person, not a call center.

How to read the iron line

Look for the line that says Iron (sometimes Fe or Total iron). Its number is in mg/L, the same as ppm. A caller with 25 on his report asked me, "MGL is not parts per million, is it, though?" It is. MGL and parts per million are the same.

A "<" sign, or ND for "not detected," means the amount was too small for the lab's equipment to see. The number after the sign is the lowest the lab can measure. On 69 of the 326 reports my customers got back, iron came back only as "<2," because those reports used a limit of 2 for iron. The rest used limits of 0.05, 0.1 or 0.2. So a "<2" can't tell 0.3, which stains, from zero. If you have orange stains and a "<2," trust the stains and text me the report.

When a number looks wrong, check the decimal and the unit, then retest. One customer's lab report came back at 119 ppm while a local test said 4.5 to 5. The highest we have ever treated is 50, so I told him to have a local lab retest the iron before he bought anything.

Which type of iron you have

If you pour a glass of your well water and an hour or two later it turns orange, that's clear water iron. If it comes out of the faucet orange, that's red water iron. The first is ferrous iron, the second ferric iron. Clear water iron is the kind I find most often in well water. The lab gives you one number for both kinds, total iron, so the glass tells you which kind you have and the lab tells you how much. The kind matters for the fix, so tell me what the glass did when you send your report. Ferrous vs ferric iron goes through the glass test step by step.

Slime that builds up in the toilet tank, floats to the top and has a disgusting smell is a third thing, iron bacteria, and it's the one I run into least. Our lab test doesn't check for it, and we don't sell a test for it. Iron bacteria in well water covers what to look for.

How to take the iron sample

Take the iron sample from a cold tap before any softener or filter, and let the water run first. That way the number is your well's, not your pipes' or your filters'.

• Before any treatment. A sample drawn after a softener or filter tells you what gets through it, not what is in the well. One caller's lab showed 0.06 iron, but his sample had gone through 3 sediment filters first, and a bucket of his well water settled out brown overnight.
• Let the water run. Extension services tell well owners to run the water before an iron sample so it comes from the aquifer; North Dakota State says 15 minutes. Our kit has you fill one bottle before you run the water and one after about 5 minutes. Follow the kit's instructions for which is which.
• Old metal pipes or a galvanized tank. People ask me, "Is it my old pipes or the well?" Typically, it's your well water. If you have metal pipes or a galvanized pressure tank, North Dakota State also asks for a second sample from inside the house.
• Ship it Monday to Wednesday. Send it the same day you collect it.

Every step of the kit, bottle by bottle, is in how to collect a well water sample.

Test for more than iron

The other numbers on the report change what fixes it. Of the 57 wells my customers tested with iron over 0.3, 51 had at least one of these as well:

If your pH is low, an acid neutralizer goes in too, and I set its place from your test. The lab test reads every one of these from the same sample; how to read your well water test results goes through the rest of the report.

Frequently asked questions