If you have iron present in your well water, it can be an unsightly scene in your bathroom and kitchen. It can leave your laundry and hair feeling unwashed, your drinking water with a metallic taste, and your fruits and vegetables spoiled. As little as o.3 ppm (mg/L) can cause these issues. Iron concentrations of up to 0.3 ppm in your drinking water isn’t really harmful to your body and is considered safe according to the EPA; in fact, it’s necessary for red blood cell production and health in general. But iron found in your water supply can be a nuisance and costly to your home, as it can clog pipes and plumbing fixtures and reduce household water pressure. Too much iron, however, can definitely cause health concerns on top of home issues.
If you have more than 0.3 ppm of iron-contaminated water, then you’ll need to look at installing an iron removal system or other water treatment system to deal with your iron problem. Depending on the type and amount of iron found in your well water as well as your water quality in general, there is a range of cheaper to more costly options for removing iron. Read on to find out what might be the best solution for you and your home.
Types of iron present in your water
It only takes as little as 0.3 ppm of iron to cause staining issues. One ppm of iron is equivalent to about one grain of sand in one quart of water.
Iron is abundant in the Earth’s crust, which is why it often makes its way into well water. Iron from well water can be present in various forms. Some are easier to get rid of than others. You may be able to tell what type of iron is in your well water just by looking at it – it might be obvious.
However, you may have multiple types, which might not be so obvious. Of course, the best way to know for sure is to do a water test so you know exactly how to deal with it.
Let’s look at the types of iron that might be lurking in your well water.
Ferric iron (Fe3+), also known as rust or orange water iron, turns your water orange. It’s a solid particle that can settle and be filtered out, just like any other sediment. This is the simplest type of iron to remove.
Ferrous iron or dissolved iron is more commonly found in deep wells where the water has not been sufficiently exposed to air for it to oxidize the iron in it.
Ferrous iron (Fe2+) is soluble and therefore leaves the water clear. However, it’ll leave orange stains on your bathroom fixtures once the water evaporates and it oxidizes. Ferrous iron is trickier to get rid of as it cannot be filtered out in its current form; it needs to be oxidized into insoluble ferric iron first so it can precipitate out and then be filtered out.
Colloidal iron is ultra-fine particles 1 micron or smaller of ferrous iron. It doesn’t settle, leaving your water cloudy and maybe a tint orange.
Colloidal iron presents unique challenges. It’s best to treat it like ferrous iron and perhaps combine it with ultrafiltration or nanofiltration if necessary.
Iron bacteria (also known as organic iron) is a type of iron bound to organic matter that forms a sludge which bacteria feed on. You’ll see orange, slimy clumps in your water – especially your toilet tank or toilet bowl – if you have bacterial iron. Combine it with bleach in your laundry or cleaning regimens and you might have permanent stains!
It isn’t harmful to your health itself, but it can cause costly damage from clogged pipes, and it doesn’t look or taste great either. And it can create an environment for other pathogens to grow since many harmful organisms require iron.
This is probably the toughest form of iron contamination to remove from your well water and is probably the most costly to remove. But there are ways to deal with it.
Methods: How to remove iron from well water
So how do you deal with these types of iron? You need a thorough and accurate understanding of what’s in your water and of the various water treatment solutions available. Here’s a list of methods of iron removal, ranging from the cheaper to the more costly options.
If you have orange water, you probably have ferric iron present. Since this type of iron is a solid particle, it can be caught by a sediment filter. Therefore, a 1-micron or sub-micron sediment filter might be the best place to start.
A sub-micron sediment filter will remove ferric iron and may help remove colloidal iron (as long as the filter is rated for particles that small). However, it will not remove ferrous iron.
- only deals with ferric iron (and perhaps colloidal if filter is fine enough)
- easy to install and use
Ferrous or soluble iron is considered a hard water mineral. If you have hard water containing ferrous iron up to 3 ppm (3 mg/L) – and only ferrous iron, no ferric – the best way to deal with it is with an ion exchange water softener. The ion exchange process exchanges the hard water minerals of calcium, magnesium, and iron for weaker cations such as sodium or potassium.
Water softeners work well across temperature ranges, in low pH water, and in water with little oxygen.
The best types of water softeners are dual-tank water softeners with counter-current flow that use softened water for the backwash cycle to regenerate the resin beads.
If you already have a whole home water softening system – which you probably do if you’re on well water – it can probably handle up to about 1 ppm of iron fairly well. You can stretch it to handle up to 3 ppm of iron if you use the following materials with it:
- water softener salt that’s specific to helping remove iron
- resin beads designed to help remove iron (fine mesh resin)
- resin cleaner that helps remove iron buildup from the resin bed
Also, you should probably adjust your salt setting up by 5 gpg per ppm of iron. You may also need to replace your valves more often if you have high iron in your well water.
If there is any ferric iron in your water in addition to the ferrous iron, you’ll likely need to install a sediment pre-filter before your water softener so as not to damage your water softening system.
If, somehow, you have soft well water containing iron, you’ll need to move toward an oxidizing filter for your ferrous water, such as greensand, birm, aeration, chemical injection or ozone.
- best for hard water with ferrous iron up to 3 ppm
- you’ll go through more salt than hard water without iron
- requires a few additional water softening materials and a bit more maintenance
- may need additional filtration for ferric iron, hydrogen sulfide or iron bacteria
Birm is another powerful iron oxidizer that can oxidize ferrous iron and dissolved manganese in water with a higher pH of 6.8-9. It is often combined with calcite to increase the pH of the water and ensure effective oxidation of the iron. Once oxidized, the insoluble ferric hydroxide iron particles then precipitate and can be filtered out.
Birm is economical in that it uses no chemicals and requires no regeneration. It also has a long lifespan as it isn’t consumed in the oxidation process, and it works well across a wide range of water temperatures.
It does require backflushing to remove the precipitated iron particles, though. No hydrogen sulfide can be present in the water, and free chlorine should be below 0.5 ppm for birm to work effectively. Dissolved oxygen needs to be at least 15% of the iron content, otherwise aeration might be required.
- best for ferrous iron and manganese
- requires high-pH/alkaline water
- requires a backflushing tank
- water must be free of hydrogen sulfide, low in chlorine, and have sufficient O2
If you can get your hands on some zeolite media, it can help soften the water by removing ferric iron, calcium and magnesium – all of which are hard-water minerals – as well as precipitated sulfur and manganese. Zeolite can also help neutralize the pH of your water, bringing acidic water closer to a pH of 7.
Zeolite is a very porous compound made of aluminum, silicon and oxygen, filtering down to 5 microns. It can easily absorb ferric iron in large quantities as well as other hard water minerals – almost like a mineral sponge – and has natural ion exchange capabilities.
Zeolite was actually the original water softening compound used before polystyrene resin was invented for municipal water softeners dealing with chlorine.
If you’re using zeolite, it will require backwashing periodically with salt brine.
- best for absorbing ferric iron
- helps soften water
- requires backflushing with salt brine
- neutralizes water to pH of 7
One type of iron filter for ferrous or clear water iron uses aeration, also known as air-over-media or air injection iron filters. The aeration iron filter tank uses air to oxidize ferrous or soluble iron, turning it into ferric iron or rust, which is an insoluble particle. The rust then settles and is captured by specific media. Aeration also works in the same way for sulfur present in your water.
Air over media iron sulfur filters are chemical free and there are no cartridges/filters to replace. They are not the cheapest option, but they’re the best solution for family homes to help remove ferrous and some colloidal iron as well as hydrogen sulfide, that rotten egg smell, from your water.
The nice thing about an air injection iron filter is that ozone injection equipment can be added onto it to help oxygenate the water, support the oxidation process, and help kill bacteria present in the water.
Aeration is most effective for water with 6 ppm of iron or less (or up to 10 ppm if it’s coupled with ozone). Luckily, iron levels above 10 ppm are rare.
The best aeration systems have the air injector installed on the side of the tank as opposed to the top (and, according to some, are coupled with ozone). This prolongs your service intervals by reducing the amount of iron sludge that will eventually clog the injector valve and media over the span of several months even with low iron levels.
Aeration is less effective at removing iron bound to organic matter (bacterial iron), however. Organically-bound iron, low pH and cold water temperatures can make aeration a less suitable option.
In addition, bacteria or mold present in the air being injected can create an unsanitary water environment, and bacteria can grow wherever there’s air in the system. So this form of iron removal needs to be well maintained for sanitation purposes.
You may want to consider consider adding on a UV purification system to kill any microbes introduced in the process.
- best for ferrous iron, colloidal iron, dissolved manganese and hydrogen sulfide
- chemical-free iron filter
- no filters to change
- requires backflushing
- can be coupled with ozone injection
- may require frequent servicing or cleaning of valves/injectors for optimal function
- can’t deal with bacterial iron
- ensure sanitation is maintained
- acidic water may require neutralizing first
- may not work as well in cold water
Chemical injection or shock chlorination is the only method to help deal with bacterial iron. However, chlorine is also a great oxidizer for ferrous iron, so you may choose chemical injection for ferrous iron issues.
If you have bacterial iron, you’ll want to shock your entire well first. However, you may find you need continual chlorination to deal with it on a long-term basis, which is where chemical injection comes in. Iron bacteria sludge will ruin all your other filtration equipment, so it needs to be dealt with first before you can filter anything else out.
Usually something like chlorine or hydrogen peroxide is injected into the water, killing the bacteria while oxidizing the iron.
If you use chlorine, then the water goes into a contact tank which gives it time to work, then into a backwash tank to remove the rust and sediment, then finally though a carbon filter to remove the chemical.
If you use hydrogen peroxide, it doesn’t require contact time, so you can install the hydrogen peroxide injector just before a catalytic carbon filter.
The upside of chemical injection is that it also helps remove hydrogen sulfide or sulfur by oxidizing it and precipitating it out while also dealing with iron and iron bacteria, killing three birds with one stone.
And because you need to use an activated carbon filtration system to remove the chlorine or chemical after the fact, you’re also getting additional filtration of your water supply.
Your water pH needs to be at least 7 for chlorine chemical injection to work. So if your water pH is lower, you’ll need to have pH-neutralizing equipment installed as well for this type of iron filtration to work.
Chlorine is suitable for treating water containing 8 ppm of iron. And of course, then the chlorine and precipitants need to be removed, requiring multiple other filters to go along with chemical injection. The chlorine injector does get clogged, so it will need periodic cleaning.
Hydrogen peroxide injection iron removal systems stay cleaner and require very little maintenance. They are a moderate to higher-priced system (though likely comparable to chlorine injection) and you’ll need to be purchasing the hydrogen peroxide on an ongoing basis (most systems have running costs).
- best for ferrous iron, colloidal iron, bacterial iron & hydrogen sulfide
- for iron bacteria, may require additional shock chlorination
- chlorine requires contact tank
- requires backflushing and carbon filtration
- a moderate to higher cost option
- requires periodic valve/injector cleaning
- requires neutral water (pH 7) to work well
Some homeowners use greensand to help filter out ferrous iron up to 10 ppm as well as manganese and hydrogen sulfide (the rotten egg smell).
Greensand is glauconite, a greenish clay mineral that is coated with manganese oxide. Manganese oxide helps oxidize the above contaminants into insoluble precipitates, which can then be rinsed out in a backwash cycle.
The downside is that greensand requires the use of chlorine or a caustic chemical called potassium permanganate to regenerate it during the backwash cycle (depending on the type of greensand you use). But the potassium permanganate doesn’t come into contact with your filtered water supply. Potassium permanganate also stains anything it touches a deep purple, which is a turn-off for many.
A pH of 7 is also needed for this method to work, so if your water pH is more acidic, you’ll need to have equipment that neutralizes the pH first before treating it.
Most experts agree that aeration or ozonation – a system with a dedicated air chamber to accomplish the oxidation process – is preferable to the greensand method for home use.
- effective for higher ferrous iron, colloidal iron, manganese & hydrogen sulfide
- regenerant stains a deep purple & is caustic
- requires water pH of 7
- requires a backwash cycle with sufficient volume and pressure
- uses a lot of water during the backwash cycle
- moderate initial cost and higher running costs
Ozone (O3-) is a chemical-free method to remove ferrous iron from well water and has actually been used for water treatment for over 100 years. Ozone oxidizes iron, as well as sulfur and manganese, which precipitate and can then be removed through backwashing. Ozone also kills bacteria, viruses, fungus and cysts, killing a few birds with one stone.
Ozone oxidizes iron and other contaminants and kills bacteria faster than chlorine and peroxide, or chemical injection, requiring less contact time and therefore a smaller contact tank. And ozone degrades quickly (from seconds up to 30 minutes), so it doesn’t need to be removed or filtered out before use like chemicals do. (The precipitated contaminants do need to be flushed out though.)
The amount of ozone required for ferrous or colloidal iron removal is 0.43 ppm for each 1 ppm of iron in the water. Ozone systems can remove up to 5 ppm of iron, manganese and sulfur. It’s recommended to use two backwashable filters (sand or carbon-type filters) after the ozone system for continuous use.
The best ozone systems use a venturi valve to suck the ozone into a pressurized tank. For serious oxidation and disinfection, do not purchase a system that bubbles ozone into the water, as most of the ozone will be wasted, making it less effective by far.
Ozone is safe, with no hazardous chemicals to purchase and store. It doesn’t create toxic chemical byproducts in your drinking water – in fact, it destroys them if they’re present. It’s more effective than chlorine at a wider range of temperatures and pH. Ozone actually saves you money in the long-run.
The reason why more people don’t use ozone is that it’s one of the more costly methods of dealing with iron in your well water. You also need a large enough ozone generator and have a large enough contact time tank to accommodate peak (not average) water usage. You may also need an air dryer in humid climates.
Some companies question the effectiveness of ozone for iron bacteria problems or for iron removal at all. There may be several reasons for this, such as being more comfortable with chlorine because it’s more common, cost, or the fact that many add-on systems bubble in the ozone which is not effective. But if done properly, ozone is a promising and cleaner water treatment method for ferrous iron, colloidal iron and to treat iron bacteria.
- best for moderate ferrous iron, colloidal iron, iron bacteria, hydrogen sulfide & manganese
- faster & more effective than chlorine
- chemical free
- more expensive upfront but lower running costs
- requires a large enough contact tank and ozone generator
- may require an air dryer
- requires backflushing
Replace your pipes or well
If you have old iron pipes running from your well to your home, these may be contributing to your iron problems. Or if your well is old, the iron casings or fixtures in the well can rust. Sometimes, replacing your well water pipes or drilling a new well is the answer.
However, this is by far the most costly option which should only be explored when your other options have been exhausted.
- a sure way to control persistent iron bacteria – for the meantime
- lowers high iron caused by old wells/plumbing
- it’s the devil you don’t know
- very costly
Summing it up
This is a lot of information to take in, but hopefully you have a better idea of how to remove iron from well water now for your specific situation. But in case you’re still unsure, here’s a quick rundown of our recommendations for your type of iron contaminated water.
Best overall: ozone
Most affordable: sediment filter, zeolite, birm, water softener
Best for ferric iron: sediment filter
Best for colloidal iron: sub-micron sediment filter and possibly aeration
Best for moderately hard water with ferric iron: zeolite media in a backflushable tank
Best for hard water with low ferrous iron: water softener
Best for moderate ferrous/colloidal iron: air injection
Best for high ferrous iron: chemical injection, ozone
Best for iron bacteria: ozone, chemical injection
Of course, if your water quality is just terrible and you need full-spectrum water treatment system, you can purchase all-in-one systems that treat just about everything.
The most important thing to do first though, according to any water treatment expert, is test your water and know what’s in it first. Without doing this, you may still be left with iron contaminated water even after installing various water systems.
Q: What’s the most affordable way to remove iron of both the ferric and ferrous type below 3 ppm?
A: One of the less expensive options is to install a dedicated backwashable iron water filter (similar to a sediment filter) combined with a water softener. These iron filtration systems work in a similar way to water softeners but use no salt. The backwashing filter deals with the rust or ferric iron as well as other sediment while the water softener deals with the soluble or ferrous iron. This will work for ferrous iron levels of up to 3 ppm, ensuring your water softener is equipped to deal with iron.
Q: What’s the best way to remove iron from well water of both the ferrous and ferric type at higher levels?
A: If you have an iron problem of both ferrous and ferric iron above 3 ppm, you’ll need a more in-depth and expensive method of iron removal that oxidizes the soluble iron, or converts the ferrous iron into ferric iron, which can then be filtered out. To do this, air injection iron filters, chemical injection iron filter, or catalytic media are your best bets, which may need to be combined with a backwashable sediment filter and a carbon filter depending on your water quality.
Q: Can KDF be used to filter out iron?
A: KDF filters are useful for removing iron but only at lower volumes and flow rates. KDF filters are more suitable for shower or countertop scenarios and less suitable for use with well water.
Q: What about polyphosphate injection for iron removal?
A: Polyphosphate stabilizes and disperses the iron in water that has low iron levels so that the water remains clear and does not produce iron stains. But this only works if your water isn’t going to be heated since heat destroys its iron-sequestering action.
Q: What about media like Pyrolox, Filox, Katalox & Katalox Light?
A: These media are forms of manganese oxide. They work very similar to greensand. They have a long lifespan (7-10 years!) and work well across a wide range of pH at iron levels of up to 15 ppm, but they are very heavy. Their sheer weight means that many wells may not have the pressure or volume capacity to lift the media during the backwash cycle to effectively regenerate it. They also use a lot of water during the backwash cycle.
Q: What about reverse osmosis (RO)? Why isn’t RO recommended for iron removal from well water?
A: Reverse osmosis systems can remove iron up to 0.3 ppm (some claim up to 1 ppm) – anything more will clog up your RO filters. In most cases, an RO system will still require a pre-filter, like a sediment filter, for iron removal. And if bacterial iron is present, you absolutely need to treat that first.