GAC20-BB Pentek Replacement Granular Activated Carbon Filter by Tier1

Price $30.99
Availability: In stock
Fits most water filter housings that require a 20-inch x 4.5-inch filter cartridge
  • Ships fast!
  • Installs quickly and easily
  • Tier1 water filters are big on performance, not on price
  • Manufactured to reduce bad taste, odor, and sediment
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The GAC20-BB Pentek Replacement Granular Activated Carbon Filter by Tier1 is manufactured for performance, but priced for value. Immediately following a quick and easy installation, this filter goes to work reducing impurities such as chlorine, bad taste, odor, and sediment. Ideal for both city and suburban applications, Tier1 filters are backed by an Unconditional Guarantee for Life of the Product. Order the GAC20-BB Pentek Replacement Granular Activated Carbon Filter by Tier1 today.

Experience the Tier1 Difference

Tier1 manufactures high-quality filtration and household products. We take creating and maintaining a healthy home seriously. Products must undergo rigorous testing and meet demanding quality expectations in order to earn the Tier1 badge. Every purchase is backed by the Tier1® Guarantee:

  • Guaranteed Fit
  • Guaranteed Quality
  • Guaranteed Price
Package Qty 1
Used In Brands Pentair, Pentek
Manufacturer's Id GAC-20BB
UPC 799932613890
Advertised Size (in) 20 x 4-1/2
Actual Size (in) 20 inches (length) x 4 1/2 inches (outside diameter)
Media Granular Activated Carbon
Post Filter Media Spun Polypropylene
Filter Life (gallons) 25,000
Filter Life (liters) 94635.25
Filter Life (months) 6 months
Micron Rating (Nominal) 20
Operating Temperature (°F) 40 - 125
Operating Temperature (°C) 4.4 - 51.7
Flow Rate (gpm) 4
Flow Rate (lpm) 15.14
Warranty Guarantee Unconditional Product Guarantee for Life of the Product

The TIER1-GAC-20BB is comparable with the following part numbers



  1. Turn off water supply. Press red pressure-relief button (if present)
  2. Unscrew housing. Remove large o-ring, wipe clean and set aside
  3. Discard used filter cartridge. Wash housing with dish soap and warm water using a nonabrasive sponge or cloth. Rinse thoroughly
  4. Fill 1/3 with water. Add about 1 tablespoon of bleach and scrub to disinfect. Rinse thoroughly
  5. Lubricate o-ring with clean silicone grease. Change o-ring if any damage cuts or degradation are present. Insert o-ring in groove
  6. NOTE: This step is important to ensure a proper housing seal. Make certain the o-ring is seated level in the groove
  7. Insert new filter cartridge
  8. Screw housing onto the cap and hand-tighten. Do not over tighten. Make sure cap standpipe slips into cartridge
  9. Turn on water supply. Press pressure-relief button (if present). Check for leaks before leaving installation

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