Understanding Chlorine in Water and How Carbon Filters Help

Public water in the United States comes from rivers, lakes, and wells. But along with the water itself, it often contains viruses and bacteria—like salmonella—that can cause serious health issues.

To combat these contaminants, treatment plants use chlorine. While effective, chlorine can produce potentially harmful byproducts. Fortunately, carbon filters offer a simple and reliable way to reduce chlorine levels and make your water safer to drink.

Chlorine Basics

Chlorine was discovered in 1774 but wasn’t used in water disinfection until the early 1900s. Since then, it’s played a major role in fighting waterborne diseases like typhoid and cholera.

Today, the Centers for Disease Control and Prevention deems small amounts of chlorine safe for human consumption. However, emerging research shows there could be long-term health risks associated with chlorine byproducts.

Potential Problems With Chlorine

A recent study revealed that chlorine-treated water can contain 2-butene-1,4-dial (BDA)—a toxic compound. BDAs are small and hard to detect, which explains why their risks went unnoticed for so long.

Chlorine can also react with organic matter like algae or decaying leaves to form trihalomethanes (THMs), which are odorless, tasteless, and toxic in high concentrations. While the EPA monitors THMs, their presence remains a concern.

How Carbon Filters Remove Chlorine Byproducts

Carbon filters are made from organic materials like coconut shells or coal. After being processed into a fine black sponge, the carbon is activated using heat or steam to create thousands of tiny pores.

This high surface area—one pound of activated carbon equals about 100 acres—makes it highly effective at trapping contaminants, including chlorine and its byproducts.

Two Types of Carbon Filters

• Granulated Activated Carbon (GAC): Uses coarse particles and is common in many home filters. Fast water flow but slightly lower filtration performance.
• Carbon Block Filters: Denser and more effective at filtering out contaminants, but can reduce water pressure.

Types of Water Filter Installations

Whole-House Filters: Installed at the main water entry point, these filter all water used in the home—from the kitchen to the shower.

Point-of-Use (POU) Filters: Installed at a specific faucet (like your kitchen sink), these include pitcher filters, faucet attachments, and refrigerator filters.

Regardless of the type, filters must be replaced regularly to prevent bacteria buildup and to maintain effectiveness. Most systems come with indicators to signal when it’s time for a replacement.

What Do Carbon Filters Remove?

• All 32 organic compounds found in drinking water
• Common herbicides and pesticides
• PFOs used in carpets and packaging, which can cause liver damage and cancer
• Pharmaceutical residues and agricultural runoff
• Volatile organic compounds (especially from private wells)
• Chlorine and dangerous byproducts like BDA and THMs

Importantly, carbon filters do not remove helpful minerals like magnesium, potassium, and calcium. So you get cleaner water—without stripping away what’s good for you.

Find the Right Carbon Filter for Your Home

Now that you understand the risks of chlorine in water—and how carbon filters can help—you’re better equipped to choose the right solution for your home. Whether you need a whole-house filter or a POU system, carbon filtration offers dependable protection for your family.