Pentair Pentek RFFE20-BB Big Blue Water Filter - Whole House Iron

In this review the Pentair Pentek RFFE20-BB Big Blue water filter is evaluated for households dealing with dissolved iron in well water. The bottom line: it is a practical, whole-house replacement cartridge that specifically targets iron up to 3 PPM, improving taste and removing rust stains across plumbing fixtures. Our review finds it best for homes that need a simple, drop-in solution for iron-related staining and metallic taste without reworking existing 20 in Big Blue housings.

Key Features

• Iron reduction up to 3 PPM: Effectively reduces dissolved iron at typical well-water levels to improve water clarity and remove metallic taste.
• Whole house protection: Designed for installation on the main water line so sinks, toilets and appliances are protected from rust stains and iron buildup.
• Big Blue compatibility: Fits all 20 in Big Blue housings and replaces any 4.5 in x 20 in iron-reducing cartridge for easy swap-in replacement.
• Radial flow design: Cartridge construction promotes even flow and contact with the media for consistent iron reduction across the filter life.
• Quarterly replacement interval: Recommended replacement every 3 months for a family of four at 3 PPM, which simplifies maintenance planning.

Who It's For

The Pentek RFFE20-BB is best suited to homeowners with well water who see red or brown staining on fixtures, notice a metallic taste in water, or want point-of-entry protection for appliances. It is a convenient option for those who already have or plan to use a 20 in Big Blue housing and prefer a cartridge they can replace themselves without changing plumbing fittings.

Households with iron levels well above 3 PPM, or users seeking multi-contaminant removal (chlorine, chloramines, heavy sediments plus iron) in one cartridge should consider a different, multi-stage approach or a professional water treatment system. This cartridge is focused on iron reduction, not broad-spectrum filtration.

Pros & Cons

Pros

• Reliable removal of iron that prevents rust stains on sinks, toilets and plumbing fixtures.
• Improves water clarity and taste by removing dissolved iron up to 3 PPM.
• Direct replacement for any 4.5 in x 20 in iron-reducing cartridge and fits all 20 in Big Blue housings.
• Simple maintenance schedule - replace every 3 months for a family of four at 3 PPM.

Cons

• Limited to iron reduction up to 3 PPM and not a substitute for full multi-contaminant treatment.
• Ongoing replacement cost may be a consideration for some buyers, with mixed opinions on value for money.

Specifications

Brand	Pentek
Model	RFFE20-BB
Size	20 in x 4.5 in
Type	Whole house radial flow iron reduction cartridge
Iron reduction capacity	Up to 3 PPM dissolved iron
Housing compatibility	Fits all 20 in Big Blue housings
Recommended replacement	Every 3 months (family of four at 3 PPM)

Our Verdict

The Pentek RFFE20-BB is a targeted, reliable choice for homeowners with moderate dissolved iron in well water who want whole-house protection and straightforward maintenance. It removes iron-related staining and improves taste, fits standard 20 in Big Blue housings, and is a sensible value if iron is the primary issue rather than a wide range of contaminants.

Frequently Asked Questions

How often should this cartridge be replaced?
Manufacturer guidance recommends replacing the cartridge every 3 months for a family of four treating up to 3 PPM dissolved iron.

Will this remove all types of iron and sediment?
This cartridge is designed for dissolved iron reduction up to 3 PPM; it is not marketed as a comprehensive multi-contaminant or sediment-only solution.

Does it fit my existing system?
The cartridge fits any standard 20 in Big Blue housing and replaces any 4.5 in x 20 in iron-reducing cartridge for an easy swap.