Why Your Water Tastes Like Metal (Copper vs Iron, and How to Tell)

If someone calls me and says, "My water tastes like metal," it's one of two things. Either the water is acidic and it is dissolving your copper pipes, so there is copper in the glass, or there is iron in the well. The two need completely different equipment, so the first job is figuring out which metal you are tasting. Your sinks and tubs usually give it away before any test does.

What do you see besides the taste? Tap it.

Blue-green stains Orange stains Just the taste

Blue-green points to copper from acidic water. Orange points to iron. No stain at all? Start with the cold-tap check below.

The Two Causes of Metallic-Tasting Water

After 32 years of taking these calls, when someone says "my water tastes like metal," it is one of two things nearly every time:

• Copper from your own plumbing. If your well water is acidic (low pH), it slowly dissolves the copper pipes it flows through, and that dissolved copper is what you taste. Copper is not usually in the groundwater that feeds a well; it gets in on the way through the house. The water left the well tasting fine, and your plumbing added the metal.
• Iron from the well itself. Rain soaks down through iron-bearing soil and rock and dissolves iron on the way, so the water arrives at the house already carrying it. The EPA lists a metallic taste for iron above 0.3 ppm. A caller in September had a 12 ppm iron reading, and his words were "the water comes out clear ... you can definitely taste the iron."

Most people don't call it copper or iron; they call it metal. One caller told me her well was "high in metal ... It's rusty," and I asked, "You mean high iron?" Another wanted "one of those metal remover things." That is an iron filter, but only if it is iron.

The difference matters because the fixes don't overlap. An iron filter does nothing for acidic water, and a softener is not an iron filter either: that 12 ppm caller had been offered a softener that "only treats up to 5 parts per million."

How to Tell Copper From Iron at Home

Run the cold tap for a minute: if the metal taste fades, it is coming from your pipes (copper); if it stays, it came in with the water (iron). Water that sits in copper pipe overnight picks up the most copper, which is why the Minnesota Department of Health tells people to let the water run 30 to 60 seconds when it has not been used for six hours. Iron is in the water before it reaches the pipes, so running the tap doesn't change it. That part is my inference from where each metal comes from; the stains and a lab test confirm it.

Plenty of houses have both. Of the tests my customers send in, about one in six comes back acidic and about one in six has iron over 0.3 ppm, and about one in five of the acidic ones has iron too (15 of 71). A customer once called whose water tasted metallic and ran a rusty color, and he wanted to know which one he had. Beyond a visual inspection, the only way to know for sure is to analyze the water.

A hardware-store test strip kit will tell you fairly accurately what your pH is and whether you have iron, which is a fair first look. Strips won't give you a copper or lead number you can size equipment on, though; the lab numbers are what size the equipment. If you see blue-green in the tub, the guide to blue-green stains goes deeper on that one sign.

Is Metallic-Tasting Water Safe to Drink?

It depends on the cause. Iron at typical well levels is an aesthetic problem, not a health hazard. The Minnesota Department of Health says iron in water does not usually present a health risk, and the EPA's 0.3 ppm line for iron is a taste and stain limit, not a health limit.

Copper is different. The EPA's action level for copper is 1.3 ppm; short-term exposure above it can cause stomach upset, and the Minnesota Department of Health adds that infants and people with Wilson's disease may need even lower copper. Acidic water is where the high copper shows up: in the tests my customers send in, copper came back over 1.3 ppm in about one acidic tap in six (13 of 71), against about one in a hundred at pH 7 or higher.

The bigger worry in an older house is lead, and you can't taste lead at all. Homes built before 1986 often have copper pipe joined with lead solder. As I tell callers, lead usually isn't in a well unless the house "has old copper pipes where they use lead solder and the water's acidic and breaks down the joints." A metallic taste in an older house with acidic water is a reason to test for lead, not proof that it's there. Until you have numbers, the EPA's advice holds: drink from the cold tap, run it first if it has been sitting, and know that boiling does not remove lead. More on this in is acidic water safe to drink.

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One certified lab test, mailed to you, run by an accredited lab, reports pH, iron, manganese, copper, and lead from one kit, so you know which metal you are tasting before you buy anything.

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How to Fix the Copper Taste

Copper taste stops when the water stops being acidic. On a well, that means a calcite neutralizer where the water enters the house. Water flows up through a bed of calcite, which is crushed limestone. The acidic water dissolves just enough of it to come up to neutral, and neutral water stops dissolving your pipes. No chemicals and no electricity. The non-backwashing kind needs no drain line.

Your pH number picks what goes in the tank. Plain calcite handles water down to pH 5.5 in the 2.0 and 2.5 cubic foot tanks and down to 6.0 in the 1.0 and 1.5. Below that, a little FloMag (a faster-acting magnesium mineral) is blended in with the calcite. The calcite dissolves by design, so a 2.5 cubic foot tank needs calcite added about every 30 to 36 months. How to add calcite has its own guide.

Non-backwashing acid neutralizers run $1,195 to $1,695 by size. One buyer had a plumber put one in, took pH 6 water to about 7.4, and wrote: "Had the water retested by a lab and the copper is well below the threshold for concern. And the water tastes great!" The step-by-step for acidic water is in how to fix acidic well water.

How to Fix the Iron Taste

Iron taste needs an iron filter. It turns the dissolved iron into particles and catches them in a bed of media. Ours hold a pocket of air at the top of the tank; the air oxidizes the iron as water passes through, and Katalox Light (a catalytic filter media) catches it. The same tank takes out up to 30 ppm iron, 15 ppm manganese, and 10 ppm hydrogen sulfide, with no chemicals and no salt.

It cleans itself. The valve ships programmed to backwash every day and can be set to go less often. Each backwash sends about 70 gallons (1.5 cubic foot) or 140 gallons (2.0 and 2.5 cubic foot) to a drain, so it needs a drain nearby, 1/2 inch drain tubing, and an outlet. The media lasts 6 to 8 years, and then you put new Katalox Light in the same tank. The iron filters run $2,095 to $3,295 by size. How often and what to expect over the years is in iron filter maintenance.

A brand-new filter can make the water taste like the media for the first week or two. When a buyer called about that, I told him to run it for a while and backwash it a few times.

When the Test Shows Both

When the water is acidic and has iron, the neutralizer goes first and the iron filter goes after it. An iron filter works best with the pH up around 8, so the neutralizer raises it before the water gets there. With iron above 0.5 ppm, the neutralizer has to be the backwashing kind, because the iron it catches in the calcite has to be rinsed out to a drain.

A softener, if you need one, goes after both. The backwashing kind costs more than the non-backwashing kind; backwashing or non-backwashing walks through the difference.

Have your pH, iron, and copper numbers?

Text Aidan a photo of the report

Send a picture of your lab results and Aidan will tell you whether it is copper, iron, both, or neither, and which tank goes first.

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

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City Water That Tastes Like Metal

On city water, the metal usually comes from old pipes in the house or the street, and a well neutralizer is not the fix. Your water utility already monitors how corrosive its water is, to keep lead and copper out of it. When a caller in an apartment on city water told me the test was high in copper, I said it "could be coming from somewhere else in the lines, like from the main water supply."

What helps depends on the pipe. Copper from household plumbing is worst after the water sits, so run the cold tap first and use cold water for drinking and cooking; hot water pulls more copper out of pipe. Rusty, metallic water from old galvanized or steel pipe is the pipe itself corroding, which is a plumbing problem, not a water treatment one. For the drinking water in the meantime, "the only thing that would take the copper out is a reverse osmosis system under the sink." Carbon and pitcher filters typically don't remove copper. The certified city water test reads what is actually at your kitchen tap, which the utility's report does not.

A Licensed Plumber Should Install It

We recommend a licensed plumber for either tank, and I support your plumber by phone at 800-460-5810. A plumber typically finishes in two to three hours. We are an online store and ship nationally; we don't install anywhere.

Know what arrives so nothing surprises you or your plumber. Every tank ships empty. The calcite or Katalox Light ships in separate bags and is poured into the tank at install through the included fill funnel. The bypass valve comes already on the control valve. Drain tubing is not included: the iron filter and a backwashing neutralizer need 1/2 inch tubing to a floor drain, utility sink, or standpipe, from any hardware store. The step-by-step for the neutralizer is in how to install an acid neutralizer.

What Buyers Wrote About the Taste

These are verified purchases, newest first, from people who had the metallic taste, the stains, or high copper before.

Frequently Asked Questions