With more than 30 years’ experience in the residential and commercial water treatment space, Mark Nelson is a Class 1 Drinking-Water Operator and a CBWA (Canadian Bottled Water Association) Certified Plant Operator. As founder and president of Nelson Water in Ottawa, Mark focuses on dealing with challenging water treatment system designs for problem water. He also heads the largest water bottling plant in the city of Ottawa with a delivery network throughout the Valley.

The local water treatment plant removes many contaminants, but some remain or they are added to the water later as it travels through the delivery network. For this reason, many people want their own water filtration system to ensure that they have fresh and clean water. But, there are many options, it’s hard to find good information and it’s easy to make the wrong decision. In this article, we will take a closer look at the subject in more detail to help you make an informed purchasing decision.

1.  Understanding What is Water Filtration?

At the very basic level, water filtration is best described as the removal of unwanted contaminants using mechanical, biological or chemical media. There are many different methods of water filtration and some are more suited to commercial and industrial applications. For the purpose of this article, we will be focusing on the factors that affect residential water filtration.

As you will notice during this article, some water filtration systems are better at removing certain contaminants than others. Depending on the makeup of your water supply, you may require multiple systems to remove a wide variety of contaminants. These would be typically installed in series, so the water would pass through them in sequence to remove the pollutants to make the water cleaner, fresher and safer.

The best overall filtration method is a reverse osmosis (RO) system with an activated carbon filter to give the water a final “polish”. We will look at these two systems in more detail later,  but first we need to look at the relationship between water filtration and softening.

2.  Water Softening vs. Water Filtration

At first glance, these two water cleaning methods may seem similar but they are quite different in practice. Water filtration systems are designed to remove contaminants that can include: chlorine, microorganisms, heavy metals, pharmaceutical byproducts, nitrates, nitrites and more. A water softener is more focused on the removal of minerals that can cause a number of problems in your home, including: calcium carbonate, magnesium, iron and certain heavy metals. The best modern water softeners do remove a few extra contaminants and there can be a little crossover with filtration systems. A prime example would be a water softener with a dedicated iron filter.

There are a few water softening methods, but the most effective is an ion-exchange system. The mineral ions that cause the buildup of scale are replaced with more benign sodium (salt) ions and this makes the water easier to use. The water is passed through a bed of resin media and the mineral ions are left behind on the surface of the resin beads. Periodically a regeneration cycle takes place, this is the flushing of the resin to remove the hard mineral ions that coat the surfaces. This is essential because the resin beads will become less effective as they are coated with mineral ions.

To make the situation even more confusing, there are water filtration systems that soften the water. A prime example is the aforementioned RO filtration system which captures mineral content on the surface of a semi-permeable membrane with other contaminants. This is the ideal solution if you want slightly softer water and you want to remove microorganisms, solvents, pesticides, disinfectant byproducts, and many other contaminants. Some of this functionality can be added to a water softener if an activated carbon pre and post-filter is installed. To cover all the bases, most people install a RO filter and a water softening system in their homes. This provides them with cleaner water for drinking and cooking at the kitchen sink and high quality soft water for every other plumbing fixture.

3.  The Water Contaminants

Most of us are supplied with water from a water treatment plant where basic disinfection and filtration processes are carried out. The water is basically clean, but any breaks in the water delivery network or a failure can result in contamination. There are some contaminants that are not even removed because they have not been placed on the list of harmful pollutants. Each year, many water cleanliness violations occur, the water infrastructure requires significant investment and that’s not likely to happen any time soon. The exact makeup of the water in your home can vary a great deal from other areas due to the geography and activities that take place. Let’s take a look at some contaminants that have been discovered in tap water across Canada:

  • Chlorine and Chloramine disinfectants and byproducts.
  • Microorganisms such as bacteria, viruses, and cysts.
  • Heavy metals, including lead, iron, copper, and more.
  • Perfluoroalkyl and polyfluoroalkyl substances commonly referred to as PFAS.
  • Industrial grade solvents.
  • Pharmaceutical byproducts.
  • And more.

For this reason, it’s a good idea to get your water tested at a laboratory. When you know which contaminants are present in your water, it’s easier to find the right filtration method. If you’re not sure how to proceed, contact your local water treatment specialist today.

4.  Reverse Osmosis (RO) and Activated Carbon Filtration

These are the two main filtration types, when they are used together they can get the water cleaned to a very high standard. Add a water softener and you will be amazed at the quality of your water at home. Let’s take a look at them in more detail:

Reverse Osmosis: The incoming water is forced through a semi-permeable membrane under pressure. The membrane pores are extremely small and only water molecules can pass through with some minor exceptions that prove the rule. This type of filtration method can remove many contaminants, including arsenic, fluoride, sulfates, nitrates, phosphorus, calcium, magnesium, heavy metals, microorganisms, and more.

Activated Carbon: Charcoal has been used to filter water for centuries because the surface area is large in comparison to the size. The pores in charcoal (carbon) are very effective at trapping a wide variety of contaminants, including pesticides, PFAS, Volatile Organic Compounds (VOCs), disinfectants, and their byproducts, industrial solvents, and more.

In Conclusion

As you can see, there is some crossover between a RO system and activated carbon. But, they are effective when used in tandem, if you have extensive water quality issues to overcome. It’s also important to carefully consider your desired water output because the volume of water you need each day can affect your final filtration choices. If you want to learn more about choosing the ideal water filtration system to meet your needs, contact us today.