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You may have come across different filters if you’ve been considering a water filtration system for your home. For water filtration, there are a variety of different purification systems, each with its own pros and cons. However, when it comes to filters, there are only two common types of filtration to consider: carbon filters vs. reverse osmosis.

While both have their unique advantages, understanding how each one works is essential if you want to install one for your home.

Carbon Filters

Carbon filtration is one of the oldest technologies in the world. It comes in many forms, from basic “carbon gravel” systems like those in a Brita filter to more sophisticated modern filters. Sometimes called “activated carbon filters” or “carbon block filters,” these systems work by running water through a carbon medium. As water moves through the filter, impurities like chlorine and iodine bond with carbon, removing them from water and reducing the taste and odor of the water in the process. Carbon filters are common in many applications, from standalone purification systems and simple handheld pitcher filters to appliances like refrigerators and aquariums. 

Reverse Osmosis Filters

Similar to carbon filters, reverse osmosis filters also run water through a filter. However, it forces the water through a semipermeable thin film composite (TFC) membrane instead of a carbon composite. The membrane’s openings are so tiny that the filter separates water molecules from other molecules present in the water. Reverse osmosis filters usually include multiple stages, each aimed at removing a specific kind of contaminant. 

Pros and Cons in Both Filter Types

In the debate between carbon filters vs. reverse osmosis filters, the two are very different in their technology and results, so understanding the purpose of each is essential when deciding between them. Let’s look at what each system does and discuss some of the pros and cons of each. 

Carbon filters are perfect for removing chlorine taste and odor and catching large particulates on the most basic level. In contrast, reverse osmosis can remove almost microscopic particles from your water but doesn’t work as well as carbon filters at removing smells. These systems also work better if water has already been pre-filtered before the water encounters the membrane because the larger particles can damage the filter.

When it comes to small particles, reverse osmosis removes far more from the water than carbon filters do on their own. In the United States, each carbon filtration system is rated by the National Science Foundation based on the size of the particles it can remove, from 50 microns (50μm) in the least strict to half a micron in the best ones. (For reference, human hair typically measures around 100μm.)

The scale for NSF ratings for carbon filters has six levels: Class I (0.5μm to 1 micron), Class II (1 to < 5 microns), Class III (5 to <15 microns), Class IV (15 to < 30 microns), Class V (30 to < 50 microns), and Class VI (> 50 microns). These ratings apply to specific filters rather than the entire water filtration system. The NSF and the American National National Standards Institute jointly developed a scale to rate a water treatment system’s final product. 

Class I filters provide the most purification, getting rid of approximately 85% of .5–1μm-sized particles. The best systems can remove up to 99.99% of the chlorine in the water, organic compounds, and heavy metals by chemically bonding as the water passes through the filter. 

Because the TFC membrane’s pores are so tiny, reverse osmosis systems can filter particles as small as .001μm, leaving water extremely clear of contaminants without chemically bonding with chemicals like iodine, which can leave the water with a distinctive odor. 

Many water purification systems use multiple stages incorporating both carbon and reverse osmosis filters to leave water clear of contaminants and neutral smelling and tasting. These systems can include as many as 20 individual steps, although most consist of 4 or 5 steps, which is sufficient for private use.

On a federal level, the US Environmental Protection Agency’s Safe Drinking Water Act provides a mandated water treatment standard. Still, these standards serve as a minimum rather than a guide for what you may need. Choosing the right filtration system for your home depends on your priorities and the water conditions in your area.

Municipal water usually requires some level of filtering by law, and local regulations may not provide enough cleaning for your family’s needs. In addition to not clearing out extremely fine chemicals, municipal water treatment plants often use chemical disinfectants like chlorine, which is then converted to chloramine by the standard carbon filters. Chloramine is more stable than chlorine, meaning that it doesn’t dissipate or create other chemical by-products, but that also means that it’s harder to remove than chlorine. Installing a special catalytic carbon can separate the ammonia from the chlorine and turn it into chloride, reducing the water’s harsh chemical smell. 

The Science of Water

At The Science of Water, we assess and install water filtration systems to meet your unique needs. Using filtration technology backed by NASA and the EPA, our advanced water systems purify your water supply to the highest standard. Whatever you’re looking for in a water filtration system, we can help you enjoy safer, clearer, and more delicious water through every tap and appliance in your home.

Don’t wait to find out about contamination when it’s already too late. Proactively protect your household with pure, delicious water that can be relied on. For more information about The Science of Water or to book your free water test, just get in touch with our team today!