The cost of a carbon filtration system can vary depending on the size, type, and complexity of the system. For a basic point-of-use system, such as an under-sink or countertop unit, prices typically range from $50 to $300. For a whole-house carbon filtration system, which treats water for an entire home, costs can range from $500 to $3,000 or more, depending on capacity and features. Installation costs may add another $200 to $1,000, depending on the difficulty and your location. Regular filter replacements also add to the overall long-term cost.