If you’re hoping to banish iron from your drinking water, you’re probably wondering which is best: a water softener or an iron filter?
I’ve tested several water softeners and a few whole-house iron filters in my home with very hard water and iron in the Colorado mountains, and here’s which water treatment system I think is best for which situation.
📖 TLDR: The Main Difference Between a Water Softener and an Iron Filter & When to Choose Which System
The key difference between water softeners and iron filtration systems is that water softeners are primarily intended to address the effects of hard water (which is caused by calcium and magnesium), while iron filters are intended to be used to reduce excess iron, and are more capable than water softeners at reducing higher concentrations of iron.
Go for a water softener if you want to soften your water and reduce low levels of iron. Go for an iron filter if your water contains high levels of iron, especially if you also want to reduce manganese and hydrogen sulfide.
If you want to address hard water and high concentrations of iron, choose a water softener and iron filter combination, like the SpringWell WSSS.
Table of Contents
🚿 What Are Water Softeners?
Water softeners point of entry water treatment systems that have one main purpose: to “soften” water by removing the calcium and magnesium hard water minerals responsible for hardness.
Conventional water softening systems consist of two tanks: a softening tank (which holds the resin) and a sodium tank (which holds the salt used for softening).
🔎 How do Water Softeners Work?
Water softeners use a process called ion exchange to swap hard minerals with sodium.
The resin tank contains a bed of special resin beads, which are loaded with sodium. Calcium and magnesium are attracted to, and stick to, the resin. Equal concentrations of sodium are released from the resin bed to balance the water’s charge.
Conventional ion exchange softener units can remove iron, but only up to 1-2 PPM of this mineral. It’s also not recommended to use a water softener to treat iron-rich water without pre-treatment, as the excess iron content could cause resin fouling.
I used the SpringWell SS Salt-Based Water Softener within the SpringWell WSSS system (which combines the SS softener with the SpringWell Iron Filter). My pre-treatment water sample contained 13.71 grains per gallon of hardness, putting it in the “hard” category.
Post-treatment, my water contained just 0.34 GPG of water hardness, so the SS water softener had reduced 97.5% of hardness. This is an example of how effectively a water softener can address hard water.
My water’s iron concentration had also decreased significantly, but I can’t comment on the SS’s iron reduction abilities because I also used the SpringWell Iron Filter alongside the softener.
🤔 When Should You Use a Water Softener?
I recommend using a water softener if your primary water quality concern is hardness, and you also want to reduce low concentrations of iron.
Don’t use a water softener if your water contains ferrous iron, or more than 2 PPM of iron. Water softeners also can’t tackle iron bacteria.
Further Reading:
🚰 What Are Iron Filters?
An iron filter is a type of water filter that’s designed for ferric and ferrous iron removal.
This filter is typically installed at your home’s point of entry to treat water before it can travel through your plumbing, preventing staining and rusting in the pipes, fixtures, and water-using appliances around your home.
🔎 How do Iron Filters Work?
There are a few types of iron-removal filters available today. Some use chemical treatment, using an oxidant like chlorine to convert iron into a form that can be easily removed from water.
The SpringWell WSSS (which I have personally tested) uses an air injection oxidation system, which exposes water to an air bubble. The oxygen causes the ferrous iron to oxidize into insoluble ferric iron, and it’s then trapped in the greensand fusion media bed.
This same process can also address hydrogen sulfide and manganese, which are often found alongside iron in groundwater.
Air injection/oxidation has been proven to effectively reduce iron and hydrogen sulfide, and my own test results confirmed the effectiveness of this process for iron removal.
My test water contained 2.37 PPM of iron – so too much to rely on a water softener to remove. 0 PPM of iron was detected in my post-filtration water test, telling me that the system had eliminated 100% of this contaminant.
The WSSS also reduced a handful of other metals, including 100% chromium, cobalt, and vanadium, 98% strontium, 94% barium, 90% nickel, 56% copper, 50% selenium, 43% boron, 41% zinc, and 33% molybdenum.
🧐 When Should You Use an Iron Filter?
I recommend using an iron filtration system if your water contains more than 1-2 PPM of ferrous and/or ferric iron – especially if your water contains iron bacteria.
You’ll also need an iron filter to reduce manganese and hydrogen sulfide, as well as other metals, which are less effectively addressed (or not addressed at all) by a water softener.
📑 Final Word
You should now know when you might need an iron filter, and when a water softener is best.
But it’s common for well water to contain excess calcium and magnesium and high natural iron concentrations – that was certainly the case for my own water supply.
In that case, you might be keen to remove iron and soften your water with one configuration, rather than two separate systems. I’ve found that whole-house iron filters and water softener combos like the SpringWell WSSS tend to be the best solution here in terms of convenience, practicality, and value for money.
If you haven’t already tested your water, start there. Once you find out what your water contains, you can determine the best method of addressing your water quality concerns.