Three-stage vs One-stage Filter: What Are They and How Do They Differ?

Three-stage vs One-stage Filter: What Are They and How Do They Differ?
Three-stage vs One-stage Filter: What Are They and How Do They Differ?

Three-stage vs One-stage Filter

As more and more people become aware of the health implications of drinking unclean water, it has led to more options for water purification.

For example, people with really poor water sources like private wells typically opt for a three-stage filter, while those with good tap water may simply rely on a single stage water filter system.

Each of these models has features that make them attractive, which will be covered in this article. Continue reading to make an informed choice the next time you are searching for a filtration system.

What is a 3 stage water filter?

Three-stage filters have three stages of filtering water before it reaches your faucet. 

What is 1st stage filter? This is the pre-filter that removes sediment and dirt before moving to the 2nd stage. Each additional filter increases the effectiveness of the filtration process and reduces the number of impurities found in your water.

Each stage has its own function and process. The first stage typically uses a 5-micron pre filter to remove sediment, dirt, rust, and dust from the water. This is all about improving the appearance of the water. 

The second stage uses a submicron filter to remove bacteria, chlorine, and other contaminants. This is the core of the purification process because it is here the main culprits are handled. 

The second stage takes care of mineral elements like:

  • Aluminum
  • Cadmium
  • Chlorine
  • Copper
  • Iron
  • Lead
  • Mercury
  • VOCs
  • Zinc

The third stage is the final stage and essentially removes odor, bitterness, and taste.

At the end of these three stages, you have fresh drinking water that is clean to look at, safe to drink, and free from odor and bad taste.

Typical features of this system are:

  • The carbon sediment pre-filter
  • The RO membrane
  • The post filters

Three-stage vs One-stage Filter

Definition of One-stage filtration system

The single-stage/ one-stage filtration system is a method of water purification that uses one filter element to remove particles and chemicals from the water. It contains a carbon block or granular activated carbon, which removes dissolved solids and minerals.

It's a great choice for households with small or medium water needs. Another good news is that the replacement water filter for single stage is easy to install and maintain, and is usually found at the point of use, as in-line, countertop, or under-the-sink water filters.

Features of this system include:

  • Single cartridge filter
  • Easily installs to POU
  • Can contain multiple filtration media to reduce sediment, odor, chlorine, and other heavy metals.

The main differences between a single-stage and a three-stage filtration system

The main difference between a single-stage and a 3 stage water filter system is the number of stages and filters involved. 

A single-stage system uses one filter, whereas a three-stage system has multiple filters. 

  • Single-stage filters only remove large particles from water, while the 3 stage filter removes all sizes, and unwanted minerals. The multiple filters of the 3 stage whole house water filter can target different types of contaminants.
  • Three-stage filtration systems are more thorough and can make it easier for you to drink clean water. This is because a three-stage filtration system typically includes a pre-filter, a reverse osmosis filter, and a post filter or polishing filter. These are not found in the single stage filtration system.
  • The cost of replacing three-stage filters is higher than replacing single-stage filters.
  • Whole house single stage water filter systems are ideal for homes with small amounts of groundwater contamination while 3 stage filters are the go-to option for highly corrupted water.

NB: Both options, like the ones available at FILTERWAY, produce clean, clear drinking water. However, this depends on the state of the water source.


As you can see, the three-stage and one-stage filters have their respective applications and features. Whichever you choose though, it's important that you and choose a product that matches your water needs and the level of contamination in your area.