Pentek RFC-20BB Big Blue Carbon Water Filter - Whole House GAC

In this review of the Pentek RFC-20BB Big Blue carbon water filter, the bottom line is simple: it is a practical, long-lasting replacement cartridge for whole house systems that need reliable chlorine and odor reduction without sacrificing flow. The reviewer found it best for homeowners with municipal or well water who want improved taste and reduced chlorine smell across the entire house. Its radial flow design and granular activated carbon deliver effective filtration while maintaining water pressure, making it a straightforward swap for standard 20 in Big Blue housings.

Key Features

• CLEANER, BETTER-TASTING WATER: Granular activated carbon reduces chlorine taste and odor and helps improve overall water quality for drinking, cooking and bathing.
• HIGH-PERFORMANCE DESIGN: Radial flow technology minimizes pressure drop and reduces carbon fines so water pressure remains steady during use.
• LONG-LASTING FILTRATION: A 100,000 gallon capacity offers extended service life, typically up to a year depending on water quality and usage.
• VERSATILE COMPATIBILITY: Sized to fit standard 20 in Big Blue filter housings and replaces most 20 in x 4.5 in carbon cartridges for easy installation.
• CERTIFIED QUALITY: NSF/ANSI Standard 42 certification confirms material safety and structural integrity for reliable performance.

Who It's For

The RFC-20BB is aimed at homeowners with whole house filtration setups who want a no-fuss replacement cartridge that improves taste and removes chlorine and common contaminants. It is especially useful for those on city water noticing chlorine odor, or well owners dealing with low-tide smells and taste issues.

Those seeking fine particulate polishing below 25 micron, specialized chemical removal beyond standard GAC capabilities, or compact under-sink cartridges should look elsewhere; this cartridge is designed for point-of-entry Big Blue housings and whole house flow rates rather than point-of-use systems.

Pros & Cons

Pros

• Effective at removing chlorine taste and odor, improving water flavor throughout the home.
• Radial flow design keeps pressure drop low, so household water pressure remains consistent.
• Long service life with up to 100,000 gallon capacity reduces replacement frequency for many households.
• Fits standard 20 in Big Blue housings and installs easily for most homeowners.

Cons

• Rated at 25 micron and 70 micron outer shell, so it is not intended as a sub-micron or highly specialized contaminant cartridge.
• Performance will depend on incoming water quality; very heavy sediment may shorten service life.

Specifications

Product type	Whole house carbon replacement cartridge
Size	20 in x 4.5 in
Filter media	Granular activated carbon (GAC)
Micron rating	25 micron
Outer shell	70 micron porous polyethylene
Capacity	Approximately 100,000 gallon
Certification	NSF/ANSI Standard 42 certified

Our Verdict

The Pentek RFC-20BB is a sensible, cost-effective replacement cartridge for whole house Big Blue systems that prioritizes chlorine and odor removal while preserving water pressure. It delivers good value for households that want year-long service between changes and straightforward compatibility with standard 20 in housings.

Frequently Asked Questions

How long does this cartridge typically last?
The cartridge is rated for about 100,000 gallon capacity, which in many homes translates to up to one year depending on water usage and quality.

Will this remove sediment as well as chlorine?
It reduces sediment down to its 25 micron rating and also reduces chlorine taste and odor through granular activated carbon, but very fine particulate or specialized contaminants may require additional stages.

Does it fit my existing Big Blue housing?
Yes, it is designed to fit standard 20 in Big Blue filter housings and replaces most 20 in x 4.5 in carbon cartridges for easy installation.