You might be wondering about the best way to purify your home's drinking water. Maybe you’ve been using standard carbon filters in your refrigerator, or a carbon filter pitcher, and have heard those may not be completely effective. Or maybe you’ve just been drinking out of your tap and saw an influencer promoting a water-filtering solution and decided to take a closer look.

Regardless, we’re glad you’re here! Our goal is to help you gather information while making it short and sweet. We’ll focus on the two most common, accessible, and effective methods; reverse osmosis and carbon filtration.

Understanding Reverse Osmosis

Reverse osmosis (RO) might sound complicated, but the basic principle is quite interesting. It's based on a natural process called osmosis, where water moves through a semipermeable membrane from an area with fewer impurities to an area with more. Think of a screen door – air can pass through, but larger objects can't.

RO essentially reverses this process by applying pressure to force water from an area of higher impurity concentration to an area of lower concentration. This process separates water molecules from dissolved solids, ions, and other contaminants.

Several factors influence how well an RO system works, including the quality of your incoming water, the pressure applied, the type of membrane used, the water temperature, and any pre-treatment steps. Unlike standard filters that trap contaminants, RO systems use cross-filtration, where the impurities are swept away, usually to a drain, preventing buildup and maintaining filter effectiveness.

Understanding Carbon Filtration

Carbon filtration uses activated carbon, which is carbon with a huge surface area due to millions of tiny pores. This large surface area allows it to adsorb impurities. Adsorption is different from absorption; it's a surface-level process where contaminants adhere to the carbon's surface.

There are two main types of adsorption: physical, where contaminants are trapped in the carbon's pores, and chemical, where contaminants bond with the carbon surface. Different types of activated carbon filters exist, including granular activated carbon (GAC), carbon block filters, and catalytic carbon filters, each with slightly different uses.

The effectiveness of carbon filtration depends on factors like contact time (how long the water is exposed to the carbon), pore size, water chemistry, the type and quality of carbon used, and the water flow rate.

What Contaminants Do They Remove?

Reverse osmosis is very effective at removing a wide range of contaminants, including:

Inorganic contaminants like heavy metals (lead, mercury, arsenic) and dissolved salts.
Fluoride
Pesticides and herbicides.
Industrial pollutants.
Microbiological contaminants (bacteria, viruses, cysts), though additional methods like UV sterilization are recommended for these.
Dissolved solids.

Carbon filtration excels at removing:

Organic compounds, including volatile organic compounds (VOCs).
Substances that affect taste and odor, like chlorine and chloramine.
Sediment and particulate matter (especially carbon block filters).
Certain heavy metals (some carbon filters).

RO systems can filter out much smaller particles than standard carbon filters, but carbon filtering excels in other areas. It appears the relationship may be more symbiotic than opposing, at least when it comes to the purest drinking water you can get.

Limitations

It's important to be aware of the limitations of each filter type when evaluating them individually:

Reverse Osmosis:
- Removes beneficial minerals.
- Generates wastewater; anywhere from a 1:1 to 3:1, clean to waste, ratio.
- may require electricity.
- Some units may require installation.
- Is not very effective at removing certain organic compounds and dissolved gasses.
Carbon Filtration:
- Is ineffective against many inorganic chemicals.
- Has limited effectiveness against dissolved heavy metals.
- Does not remove bacteria and viruses.
- Can experience bacterial growth within the filter.
- Effectiveness decreases over time.
- Is dependent on contact time.
- May not remove all compounds equally.

So who is the champion?

Well, it’s not that easy. Each filtering method is champion at removing certain contaminates.

Both reverse osmosis and carbon filtration offer valuable purification benefits, achieving truly comprehensive water treatment often requires utilizing both technologies in a combined system.

Reverse osmosis excels at removing dissolved solids and heavy metals, targeting impurities at a very fine, ionic level. Carbon filtration, on the other hand, is highly effective at improving the aesthetic quality of water by removing chlorine, organic compounds, and substances that cause unpleasant tastes and odors. Because these systems target different types of contaminants, using them together maximizes contaminant removal.

The best systems often incorporate carbon filters with RO as a standard part of their design. Carbon filters are frequently used as a pre-filter to protect the RO membrane and as a post-filter to further enhance the taste of the purified water. This strategic combination allows for a synergistic effect, ensuring a wider range of contaminants are effectively addressed.

Here at Haven Water Company, we understand the importance of this comprehensive approach. We believe the best method of filtration involves removing everything, and then choosing what YOU want to add back in. We have to call it an unbeatable paring when it comes to drinking water.

Luckily for you, we have options from some of the top brands!