Reduces chlorine taste and odor at every tap. Genuine Pentek housing, GAC carbon cartridge, bracket & wrench. NSF 42 certified.
Watch This Before BuyingMeet Aidan, your water treatment expert
Not sure if a carbon filter is what you need?Call Aidan with your water details and he'll tell you whether this cartridge carbon filter fixes your problem, whether you need a catalytic carbon tank for chloramine, or whether the real issue is iron, hardness, or sulfur. No guessing, no upselling.
✓ Genuine Pentair Pentek 20" Big Blue filter housing (model 150233), high-flow polypropylene with a built-in pressure relief button
✓ Pentek GAC-20BB granular activated carbon cartridge (4.5" x 20"), pre-installed, with a 20 micron post-filter to hold back carbon fines
✓ Heavy-duty steel mounting bracket with hardware
✓ Filter wrench for easy cartridge changes
✓ Free shipping to all lower 48 states
Protect the carbon: a 20" Big Blue sediment filter installed upstream keeps sand and grit out of the carbon bed and makes the cartridge last longer, especially on well water.
Filter Housing
Manufacturer
Pentair (Pentek)
Model
150233 Big Blue
Housing Dimensions
approximately 7" x 7" x 21"
Connection Size
1" NPT female (inlet and outlet)
Housing Material
High-Flow Polypropylene (HFPP)
Max Operating Pressure
90 PSI
Pressure Relief
Yes, built-in button on the cap
Certification
NSF/ANSI Standard 42
Made In
USA
Included Carbon Cartridge
Cartridge
Pentek GAC-20BB (part 155249-43)
Cartridge Size
4.5" x 20" (standard Big Blue)
Media
Granular Activated Carbon (GAC)
Reduces
Chlorine taste and odor, bad taste and odor
Chlorine Capacity
25,000 gallons at 4 GPM (greater than 75% reduction, 2 ppm chlorine)
Post-Filter
20 micron, reduces carbon fines
Initial Pressure Drop
approximately 5 PSI at 5 GPM
Certification
NSF/ANSI 42 (material requirements)
Replacement Interval
every 3 to 6 months, depending on chlorine level and usage
What It Does and Does Not Do
Chlorine taste and odor
Yes, primary use
Bad taste and odor
Yes
Some VOCs
Reduces some, not certified for specific VOC claims
Chloramine
Limited. Standard GAC is not a strong chloramine solution
Iron, hardness, bacteria, sediment
No, those need their own systems
On chloramine: if your city uses chloramine instead of free chlorine, standard GAC removes it slowly and incompletely. A backwashing catalytic carbon tank is the right tool for chloramine and for high continuous flow. See our catalytic carbon filter.
Most homeowners install this filter in under 1 hour. No electricity, no drain line, and no programming. Basic plumbing skills and a pipe wrench are all you need.
1Turn off the water and relieve pressure: shut off the supply (or the well pump at the breaker) and open a faucet to drain residual line pressure.
2Mount the bracket: secure the steel bracket to a wall stud with at least 8" of clearance below the housing so the sump can drop down during cartridge changes.
3Plumb a sediment filter first (recommended): a 20" Big Blue sediment filter upstream protects the carbon bed and extends cartridge life.
4Connect the plumbing: thread the 1" NPT connections into the housing head with Teflon tape, following the IN and OUT direction marked on the cap.
5Turn on and flush: open the water slowly, press the pressure relief button to bleed air, then run water for 5 to 10 minutes to flush carbon fines. Gray water at first is normal.
Correct installation order: Supply → Pressure Tank (well) → Sediment Filter → Carbon Filter (this unit) → Water Softener → UV. Carbon goes after sediment so grit does not clog the carbon bed. See the complete carbon guide →
Need help? Call or text Aidan at 800-460-5810, 7 days a week. Send your water report and he will tell you whether a cartridge carbon filter is the right call or whether a backwashing catalytic carbon tank fits your water better.
Replace the Carbon Cartridge Every 3 to 6 months
Granular activated carbon does not regenerate. Once the carbon is exhausted it stops adsorbing chlorine, so it must be replaced on a schedule, not just when it looks dirty. The GAC-20BB is rated for about 25,000 gallons of chlorine reduction. For a family of four that is roughly 3 months; lighter use stretches it toward 6 months. If the chlorine taste or smell returns, change it sooner.
Inspect the Housing O-Ring During each cartridge change
With the sump off, check the large O-ring on the housing head for cracks or flat spots and wipe it clean. A thin coat of food-grade silicone grease keeps it sealing well. Press the pressure relief button before unscrewing the sump so the housing is not under pressure.
Watch Your Pre-Filter Ongoing
If you run a sediment filter upstream, keep up with that cartridge too. Sediment reaching the carbon bed shortens its life and can cause channeling, where water slips past the carbon without real contact time.
Replacement cost: a genuine GAC-20BB cartridge runs about $30 to $50. At 2 to 4 changes per year that is roughly $60 to $150 a year for cleaner-tasting water throughout the house.
"Products came as ordered and on time. But even more than that was the help from this company prior to purchasing. Answered all my questions. Saved me a lot of money by actually caring and recommending the right thing vs what other companies were telling me." ★★★★★
Kyler B., Verified Buyer
"Great price, free shipping and sold in kit format which isn't always the case." ★★★★★
Pat R., Verified Buyer
"Mid Atlantic was a pleasure to purchase from. Delivery was quick. Aidan was super helpful. I would highly recommend." ★★★★★
Robon S., Verified Buyer
Video Guides
Watch: Best whole house carbon filter (what actually works) has 32 years of industry experience.
Best Whole House Carbon Filter (What Actually Works)
Cleaner-Tasting Water From Every Tap, Without the Chlorine Smell
Genuine Pentair Pentek Big Blue housing with a GAC-20BB carbon cartridge, 1" NPT connections, and NSF/ANSI 42 certified components.
The 20" Big Blue Carbon Filter Kit is a whole-house cartridge carbon filter built around a genuine Pentair Pentek 150233 Big Blue housing and a Pentek GAC-20BB granular activated carbon cartridge. It is designed for city water homes that want to take the chlorine taste and smell out of every tap, along with general bad taste and odor. The 4.5 by 20 inch cartridge holds enough carbon to reduce chlorine for about 25,000 gallons before it needs replacing.
Granular activated carbon works by adsorption: chlorine and taste and odor compounds stick to the huge internal surface area of the carbon as water passes through. A 20 micron post-filter built into the cartridge holds back carbon fines so you get clear water out. The housing uses 1 inch NPT connections for full flow and includes a pressure relief button that makes cartridge changes a two minute job with the included wrench.
Be clear about scope. This is a chlorine, taste, and odor filter. It reduces some VOCs but it is not a certified VOC system, and standard GAC is not a strong solution for chloramine, which needs catalytic carbon. It does not remove iron, hardness, bacteria, or sediment. For chloramine or high continuous flow, a backwashing catalytic carbon tank is the better tool, and for sediment you want a sediment filter upstream. If you are not sure which your water needs, call Aidan and he will tell you honestly.
✔NSF 42 Certified
✔25,000 Gal Capacity
✔Chlorine Taste & Odor
✔Genuine Pentek GAC
✔1" NPT Full Flow
✔Pressure Relief Valve
✔Complete Kit
Feature
Our System
Others
Housing Brand
✔
Genuine Pentair Pentek
Generic / No-Name
Carbon Cartridge
✔
Genuine Pentek GAC-20BB
No-Name Carbon
Chlorine Capacity
✔
25,000 Gallons @ 4 GPM
Unrated / Low
Carbon Fines Control
✔
20 Micron Post-Filter
None
NSF Certification
✔
NSF/ANSI Standard 42
Not Certified
Connection Size
✔
1" NPT (Full Flow)
3/4" (Restricted)
Pressure Relief Button
✔
Built-In
Not Included
Bracket + Wrench
✔
Included
Sold Separately
Housing Material
✔
High-Flow Polypropylene
Thin Plastic
Housing Brand
✅ UsGenuine Pentair Pentek
❌ ThemGeneric / No-Name
Carbon Cartridge
✅ UsGenuine Pentek GAC-20BB
❌ ThemNo-Name Carbon
Chlorine Capacity
✅ Us25,000 Gallons @ 4 GPM
❌ ThemUnrated / Low
Carbon Fines Control
✅ Us20 Micron Post-Filter
❌ ThemNone
NSF Certification
✅ UsNSF/ANSI Standard 42
❌ ThemNot Certified
Connection Size
✅ Us1" NPT (Full Flow)
❌ Them3/4" (Restricted)
Pressure Relief Button
✅ UsBuilt-In
❌ ThemNot Included
Bracket + Wrench
✅ UsIncluded
❌ ThemSold Separately
Housing Material
✅ UsHigh-Flow Polypropylene
❌ ThemThin Plastic
✔ Free Lifetime Tech Support
Every product we sell comes with free technical support for life. Questions about chlorine vs chloramine, cartridge intervals, or installation order? Call, text, or email anytime.
📞 Call Us800-460-5810
✉️ Email Supportsupport@midatlanticwater.net
🕒 Live Hours7 days a week
Frequently Asked Questions
It reduces chlorine taste and odor, general bad taste and odor, and some VOCs. It is a taste and odor filter for chlorinated water. It does not remove iron, hardness, bacteria, or sediment, and it is not a certified VOC, lead, or PFAS system. For those problems you need the matching system instead.
Not well. Standard granular activated carbon reduces chloramine slowly and incompletely. If your city uses chloramine instead of free chlorine, choose a backwashing catalytic carbon tank, which is built for chloramine and for high continuous flow. We are happy to confirm which your utility uses before you buy.
Every 3 to 6 months for most homes. The Pentek GAC-20BB is rated for about 25,000 gallons of chlorine reduction, which is roughly 3 months for a family of four. Carbon does not regenerate, so replace it on schedule. If the chlorine taste or smell returns sooner, change it sooner.
The cartridge has a 20 micron post-filter that holds back carbon fines, but it is not a sediment filter. Installing a 20 inch Big Blue sediment filter upstream protects the carbon bed from sand and grit and makes the carbon cartridge last longer, especially on well water.
It is primarily a city water filter, for chlorine taste and odor. On a well, carbon can polish mild taste and odor, but it does not fix rotten egg sulfur smell, iron, or bacteria. For sulfur or chloramine, a catalytic carbon tank is the right tool, and for iron you need an iron filter.
The housing uses 1 inch NPT connections for full flow, and the GAC-20BB chlorine reduction is rated at 4 GPM so the water gets proper contact time with the carbon. That suits whole-house taste and odor polishing in a normal home. For high continuous demand, a backwashing catalytic carbon tank handles more flow with longer service life.
1 inch NPT female threaded inlet and outlet, which matches standard 1 inch home main line plumbing. You can reduce to 3/4 inch, but that unnecessarily restricts flow.
No to both. This is a passive cartridge carbon filter. No power, no drain line, no programming, and no waste water.
20" Big Blue Carbon Fi...$259.00
Better-Tasting Water at Every Tap, Done Right
A genuine Pentek housing and carbon cartridge for $259, not a no-name shell.
The problem with cheap carbon kits
No-name carbon kits use thin housings that crack under pressure, carbon of unknown quality and capacity, and cartridges with no post-filter, so loose carbon fines end up in your water. Many also use proprietary cartridge sizes that cost more and are hard to find.
Worst of all, cheap kits rarely tell you the truth about what carbon can and cannot do, so people buy them for chloramine or iron and are disappointed.
The Real Cost Comparison
No-Name Carbon Kit
$120-180 + Carbon Fines
❌Lifespan: Fails in 3-4 years
❌Result: Frequent repairs, poor water quality, leaks
❌Support: None
Unknown capacity, cracks, proprietary refills
Best Long-Term Value
Big Blue Carbon Filter Kit
$259 + $60-150/yr Cartridges
✅Lifespan: Lasts 15+ years
✅Result: Done right the first time, peace of mind
✅Support: Lifetime USA Support
Genuine Pentek, NSF 42, ~$0.30/day Year 1
For $259 plus roughly $60 to $150 a year in genuine cartridges, you get cleaner-tasting, better-smelling water at every tap from components water treatment pros actually trust. A cracked no-name housing flooding your basement costs far more than the difference.
Why this kit
This kit pairs the genuine Pentair Pentek 150233 Big Blue housing, the industry standard, with a genuine Pentek GAC-20BB granular activated carbon cartridge rated for about 25,000 gallons of chlorine reduction and built with a 20 micron post-filter to keep carbon fines out of your water.
It is honest about scope: it is a chlorine, taste, and odor filter for city water, not a chloramine or iron system. If your water needs something else, we will tell you before you buy.
Contact Us
800-460-5810
We're here to help.
30-Day Money-Back Guarantee
Backed by 32 Years of Water Treatment Experience
The Policy: if the 20" Big Blue Carbon Filter Kit doesn't meet your expectations within 30 days of purchase, contact us for a full refund. We ship a quality product from a trusted manufacturer and stand behind it completely.
32 YrsEXPERIENCE
10,000+SYSTEMS SOLD
4.8★Success Rate
After 32 years of helping homeowners fix their water, we know carbon is one of the most over-promised products in this industry. We chose the genuine Pentair Pentek Big Blue housing and GAC-20BB cartridge because they do exactly what we say: reduce chlorine taste and odor, with real, rated capacity and honest limits.
The "Cheap Carbon" Trap
+
Generic carbon kits use thin housings that crack under pressure, carbon of unknown quality and capacity, and no post-filter, so carbon fines end up in your water. Many are sold with claims they cannot keep, like removing chloramine or iron. When they disappoint, you are stuck with a no-name housing and refills that are hard to find.
How Our Guarantee Works
1
It Doesn't Meet Your Expectations
If the kit arrives damaged, doesn't fit your plumbing, or doesn't do what you expected, contact us within 30 days.
2
We Make It Right
Call or text Aidan at 800-460-5810. We'll troubleshoot first, since many issues are simple installation fixes. If we can't resolve it, we issue a full refund.
Free Tech Support for Life
Every product we sell comes with free lifetime technical support. Not sure whether you need carbon, catalytic carbon, or something else entirely? Call us. You'll talk to a real person who knows water treatment, not a script reader.
I've helped homeowners with water for over 30 years. Carbon is great for chlorine taste and smell, but it is not magic. If you call me with your water report, I'll tell you honestly whether this kit is what you need or whether a catalytic carbon tank or another system fits better.
