Water Filter vs Water Softener

What’s the difference between a water filter vs water softener? If you’re looking to purchase one but you aren’t sure what you need or what the differences between them are, then this is the article for you.

What’s In Your Water?

Before purchasing any water purification products, you should know what’s in your water. It’s always helpful to do a water quality test to be sure, but it will depend on whether you have city water or well water and whether the water has already been treated for various things and how in-depth of treatment you’re looking for.

City Water

Typically, city water will contain chlorine (or in some cases chloramines – it’s worth checking which it is, as systems designed to remove chlorine don’t necessarily remove chloramines!). Older pipes might also experience issues such as frequent boil water advisories, making you wary of just how well-treated your water is. Most water in the US is hard, although perhaps not always hard enough to cause significant problems.

Well Water

Well water contains dirt, sand, clay, rust and other large particles. Well water will often be hard, containing high levels of minerals such as iron, calcium and magnesium. It may also contain heavy metals and chemicals and will likely also require disinfecting.

Water Filtration

How Do Water Filters Work?

Here’s the short answer to the main question of the difference between a water softener vs water filter: water softeners are a type of water filter. But there are many types and levels of water filters and water filtration systems. In short, they may work to remove impurities such as sediment, chemicals, heavy metals and living organisms out of your water.

Of course, there are showerhead water filters that only affect the water you bathe or shower in. Then there are countertop or under-sink filtration systems that filter only the water that you drink and cook with.

However, if you’re reading this article, chances are you’re looking at your options for a whole house water filtration system. This affects your pipes, appliances, laundry, skin, cleaning requirements and your drinking water. So this is primarily what we will cover.

Top Water Contaminants

There are six main water contaminants that people generally want to filter out. These include bacteria, chlorine, fluoride, lead, iron and copper. Once you know what’s in your water or what your concerns are, you can determine the type of filter you need.

Types of Water Filters and How They Work

Absorption filtration

This is the most common type of filtration and is carried out with granular activated carbon or a carbon block. Removes chlorine, heavy metals like mercury, zinc, copper and cadmium, and some sediment based on its micron rating. Granular carbon is what is generally used at the point of entry in whole house filtration as it provides adequate flow rates.

Mechanical filtration

Mechanical filters involve a screen or mesh that physically filters out particles of a certain size based on its micron rating. For example, a filter with a rating of 100 microns would filter out sediment (sand, dirt, clay, rust) while one with a 1 micron rating would remove microscopic particles.

Ion exchange filtration

This is the category of filtration that water softeners fall into. Water softeners use resin beads and salt to carry out the ion exchange process, exchanging the hard water minerals such as calcium and magnesium for sodium (or potassium or hydrogen), trapping them and flushing them out. With the right resin and salt, water softeners can also remove iron. More on this further down.


This is where a substance is isolated within the water but not removed. Some forms of water softeners work this way, such as citric acid water softeners and electronic water descalers, isolating the calcium carbonate in the water and preventing it from attaching to surfaces.

Reverse osmosis (RO) filtration

Reverse osmosis is a very effective form of filtration using water pressure to force water through a semi-permeable membrane of 0.0001 microns, essentially purifying and disinfecting the water and removing most minerals.

Removes 95-98% of calcium and up to 92% of fluoride. Produces a fair amount of waster water and requires a large holding tank of treated water to maintain adequate water pressure.

RO is often combined with other forms of filtration such as activated carbon to remove chlorine (since the RO membrane will be degraded by chlorine) and possibly a water softener to remove a large amount of hard minerals first.

Reverse osmosis water can actually become corrosive to pipes due to its lower pH since its healthy minerals have been removed, so the water often needs to be remineralized with calcium and magnesium after going through RO.

Ultraviolet (UV) light filtration

UV filtration is a form of disinfection that kills bacteria, viruses and parasitic cysts.


Water ionization produces alkaline drinking water and also removes fluoride by ionizing it into the acidic water portion. It is generally only used for countertop or under-sink filtration and is usually combined with a carbon filter.

What Whole House Filter Do You Need?

Now that you know the different types of water filtration systems available, you should be able to decide what your needs are and what sort of whole house system you need most.

We learned that water softeners are a type of water filter used to remove hard water minerals. On their own, water softeners do not remove sediment, germs, chemicals or heavy metals.

If you’re on well water, then you likely require a multistage filter for sediment and germs as well as a water softener that removes iron. Or you might opt to combine a sediment filter with a water softener and a reverse osmosis system.

If you’re on city water, then a water softener to remove calcium and save your skin, hair, appliances, hot water heater, laundry, and elbow grease might be all you need. And maybe you want to throw in a carbon filter to get rid of the chlorine, too.

Let’s explore why a water softener might be of benefit to you, regardless of your water source.

Hard Water and Water Softeners

What Is Hard Water?

Although hard water usually contains higher levels of calcium and magnesium, hard water is measured by how much calcium carbonate is in your water in terms of grains per gallon (gpg):

  • Very hard: over 10.5 gpg
  • Hard: 7-10.5 gpg
  • Moderately hard: 3.5-7 gpg
  • Slightly hard: 1-3.5 gpg
  • Soft: less than 1 gpg

The Problem with Hard Water

A Preference

Hard water or soft water might simply be a preference. Perhaps you like the taste of one more than the other. Perhaps you like the slippery feel of soft water, or maybe you hate feeling like you just can’t get soap off your skin and conditioner out of your hair with soft water. Maybe you love the feeling of softer clean clothes washed in soft water, or maybe it really doesn’t bother you at all.

An Annoyance

Hard water could be primarily more of an annoyance, causing you to have to clean things more often, like water spots, soap scum and white scale off your kitchen and bathroom surfaces, faucets and appliances.

A Health Issue

Hard water might be a health issue, such as if you have eczema, dry skin or other skin conditions that seem to be affected by the quality of your water. Soft water, on the other hand, can also be an issue. Water softened with salt can pose health risks to people with heart problems such as high blood pressure or edema due to the high sodium content.

A Household Necessity

If your water is hard enough to clog up your pipes and appliances and burn out your hot water heater due to scale buildup, thereby costing you time, worry and expenses, then a a water softener is a necessity.

How Do Water Softeners Work?

Water softeners work to remove most of the hard water minerals such as calcium and magnesium out of your water supply. Water softeners are installed at the main water pipe that enters your house before the water reaches the hot water heater or any other pipes.

Water softeners use a resin bed (usually made of a synthetic material) and salt (typically sodium chloride) to carry out the ion exchange process that softens the water, capturing calcium and magnesium and replacing them with sodium ions. You can also purchase salts that help reduce iron in your water.

The hard water minerals are then flushed out of the brine tank in a process called regeneration, releasing salty, hard water into the sewage pipe. A single regeneration uses between 20-65 gallons of water, and a system might regenerate one to four times per week depending on your water usage.

Pros and Cons of Typical Water Softeners


Water softeners reduce cleaning by reducing water spots, soap scum and scale buildup in your kitchen and bathroom.

Soft water reduces the amount of body soap, shampoo, dish soap, laundry detergent and cleaning chemicals you need to use to get the job done well. It keeps your clothing brighter, softer and less itchy. Your skin and hair will look and feel brighter and less dry with softened water.

Your hot water heater and appliances won’t have to work as hard without the scale buildup reducing their efficiency. And ultimately, your pocketbook will thank you for all the money you will save.


Of course, typical water softeners have their own expenses. Besides purchasing the water softener system, you’ll need to purchase resin beads. With cleaning it with a good cleaning solution once or twice a year and with the right brand, these can last as long as the water softener itself, although they may require replacing at least once in the life of your water softener. This can be a bit of a job but can be DIY with the right setup.

You’ll also need to fill it with one or two large bags of water softener salt every month or two. Most people purchase water softener-specific sodium chloride that contains small amounts of additives which reduce salt mushing and bridging in your brine tank, ultimately keeping your water softener working properly. However, for people with sensitive skin or other health issues, potassium chloride salt is available or salts without additives.

And then of course, there’s the expense of using large amounts of water for the regeneration process multiple times a week. This is also an environmental concern, as is releasing so much sodium into the environment. However, a potassium chloride salt can help reduce this impact, creating salt free water.

Finally, softening your water reduces the mineral content of your tap water, meaning you might have to take mineral supplements to compensate for this deficiency.

Caveat to the Cons: Innovative Water Softeners

You can erase many of these cons with innovative water softeners that don’t use salt or large amounts of water and don’t remove minerals from your tap water (see the Sequestering section in Types of Water Filters above). They simply convert the minerals into a form that cannot stick to your pipes, faucets, appliances and surfaces, meaning less cleaning, maintenance and expenses for you. You’ll get salt free water, and you’ll still be getting a healthy dose of minerals in your tap water if that’s something you want.

Wrapping It Up

We hope you’re more clear now on the difference between a water softener vs water filter, what the various types of water filtration are and which types you require, how a water softener can benefit your home and health, how to combine a water softener with other types of water filtration, what some of the precautions are with water softeners, as well as some alternatives to conventional water softeners and whether they might work for you.