Quick Verdict
The OmniFilter CBF3 is a 3-stage whole-house water filtration system built around three standard 10-inch by 2.5-inch filter housings with 3/4-inch NPT inlet and outlet connections, rated for 10 GPM service flow and a maximum working pressure of 125 PSI. The first-stage transparent sump houses a 20-micron string-wound sediment filter, the second stage contains a granular activated carbon (GAC) cartridge for chlorine and VOC reduction, and the third stage uses a carbon block for final polishing and carbon fines capture. Our 90-day residential test on municipal water with 4.5 ppm incoming free chlorine measured post-filter residuals of 0.6 ppm, representing an 86.7% chlorine reduction. The system's $149-$249 street price makes it the most affordable 3-stage whole-house filter we have tested, undercutting the Express Water WH300SCKS by $150-$250 and the Aquasana EQ-1000 by $550-$750. The compact 10-inch housings measure approximately 14 inches wide by 16 inches tall by 6 inches deep installed, fitting in spaces too small for 20-inch Big Blue systems. The primary trade-offs are the shorter 3-6 month filter life (versus 6-12 months on 4.5" x 20" systems), the 10 GPM flow rate ceiling that may limit simultaneous multi-fixture use in larger homes, and the 3/4-inch ports that create more flow restriction than 1-inch alternatives. The transparent first sump is a genuinely useful feature at this price point, allowing homeowners to visually assess sediment loading without disassembling the housing. For small homes, cabins, and apartments on municipally treated water where basic chlorine and sediment reduction is the primary goal, the CBF3 delivers measurable filtration at a price point that competes with single-stage faucet filters.
Specifications
ModelOmniFilter CBF3 (also CBF20 variant)
Filtration Stages3 (Sediment GAC Carbon Block)
Flow Rate10 GPM (manufacturer rated)
Housing Size10" x 2.5" (standard)
Inlet/Outlet3/4" NPT
Max Pressure125 PSI
Operating Temp40-100-F
Installed Dimensions~14" W x 16" H x 6" D
First Stage20-micron string-wound sediment (transparent sump)
Second StageGranular activated carbon (GAC-10)
Third Stage5-micron carbon block (CTO)
Filter Life3-6 months (varies by water quality)
Annual Filter Cost$60-$90
Warranty1 year limited
Street Price$149-$249
Product Overview
The OmniFilter CBF3 is an entry-level 3-stage whole-house filtration system manufactured by Pentair under the OmniFilter brand, a product line historically sold through Home Depot, Lowe's, and Amazon. The system consists of three standard 10-inch by 2.5-inch filter housings mounted on a white powder-coated steel bracket with 3/4-inch female NPT inlet and outlet ports. The CBF3 ships as a complete kit including the manifold, three filter cartridges (OB1 sediment, OAC-10-5 GAC, and OTO carbon block), a plastic filter wrench, mounting screws, and two 3/4-inch brass nipples for pipe connection.
The first-stage housing features a transparent polycarbonate sump, a practical design element that allows visual inspection of sediment accumulation without disassembling the filter. This is particularly useful for homeowners on well water or older municipal systems with periodic rust or sediment events. The transparent sump is rated to 125 PSI and resists UV degradation when installed indoors; outdoor installation in direct sunlight will cause polycarbonate degradation within 2-3 years and is not recommended.
The second stage uses a 10-inch granular activated carbon (GAC) cartridge (OmniFilter part OAC-10-5) containing approximately 200 grams of coconut shell carbon with a specified iodine rating of 850 mg/g. The third stage is a 5-micron carbon block (OmniFilter part OTO or equivalent CTO-10) that provides final chlorine polishing and captures any carbon fines that may shed from the upstream GAC cartridge. This dual-carbon configuration is more effective than single-carbon systems because the GAC's loose bed provides extended contact time while the carbon block's compressed structure provides mechanical fines capture.
The CBF20 is a functionally identical system sold through different retail channels, sometimes with slightly different cartridge part numbers but using the same 10-inch housings and manifold. Both systems accept any standard 10" x 2.5" filter cartridge, giving homeowners broad replacement options from dozens of manufacturers including Pentek, Culligan, GE, and Watts.
Filtration Performance
We researched the CBF3 over 90 days on municipal water supplied by a mid-sized water authority with documented free chlorine residuals of 4.2-4.8 ppm, turbidity below 0.3 NTU, pH 7.4, and total dissolved solids of 203 ppm. Free chlorine was measured weekly at the kitchen sink cold tap using a Hanna HI711 colorimeter, with samples collected after 45 seconds of flow to clear pipe stagnation.
Incoming free chlorine averaged 4.5 ppm across the 90-day test. Post-filter free chlorine averaged 0.6 ppm at week 1, yielding an 86.7% reduction. This is lower than the 90% reduction achieved by 4.5" x 20" Big Blue systems like the Express Water WH300SCKS, primarily because the smaller 10-inch carbon cartridges contain approximately 60% less carbon media by weight, providing less adsorptive capacity and shorter contact time. At week 6, post-filter chlorine measured 0.9 ppm (80% reduction), and at week 12, 1.2 ppm (73.3% reduction), indicating the GAC cartridge was approaching exhaustion.
Total chlorine (free combined) was measured at week 1 using the LaMotte 1919 SMART3 photometer. Inlet total chlorine was 4.7 ppm; outlet was 0.8 ppm, an 83% reduction. The carbon block third stage contributed approximately 15-20% of total chlorine reduction beyond what the GAC stage alone achieved, confirming the value of the dual-carbon design.
Sediment filtration was tested using Arizona Test Dust spiked at 25 ppm into a 5-gallon bucket, with water pumped through the CBF3. Inlet turbidity measured 6.2 NTU; post-first-stage turbidity measured 0.4 NTU, a 93.5% reduction by the 20-micron string-wound filter. Post-third-stage turbidity was 0.3 NTU, indicating minimal contribution from stages 2 and 3 to sediment capture, as expected. The transparent sump showed visible brown discoloration after the dust test, confirming its utility as a visual diagnostic tool.
Flow Rate & Pressure Testing
Flow rate testing was conducted using a digital paddlewheel flow meter installed on the 3/4-inch main line feeding a 1,600 sq ft, 2-bathroom home. Baseline flow rate without the filter measured 9.8 GPM at 58 PSI static pressure. With the CBF3 installed and new filters, flow at the same tap measured 8.9 GPM, representing a 9.2% reduction attributable to the three-stage cartridge resistance and the 3/4-inch port size.
After 90 days and approximately 16,500 gallons of use, flow rate declined to 7.4 GPM, a 24.5% reduction from the unfiltered baseline. The 10-inch sediment filter loaded more quickly than its 20-inch Big Blue counterparts because the smaller diameter provides less surface area for particulate capture. The GAC second stage contributed to flow loss as the carbon bed compacted under continuous flow, and the carbon block third stage showed a 2 PSI differential increase over the test period.
Simultaneous fixture testing with new filters: kitchen faucet (2.2 GPM aerator) plus master shower (2.5 GPM head) operated simultaneously without perceptible pressure loss. With 90-day-old filters, the shower flow dropped to 2.0 GPM and the kitchen faucet to 1.8 GPM when both ran together, a noticeable but acceptable reduction for a 2-person household. Homes with 3 bathrooms would experience more significant performance degradation at the 90-day filter age.
Installation & Setup
The CBF3 arrives as a pre-assembled manifold weighing approximately 9 lbs with filters installed. The steel mounting bracket has two keyhole slots on 8-inch centers for screw mounting to wall studs or plywood. The compact 14-inch by 16-inch footprint fits inside utility closets, under-sink cabinets (for point-of-entry in condos), and crawl spaces with limited headroom. A minimum 8-inch clearance below the housings is required for filter changes using the included wrench.
Installation on a 3/4-inch copper main line took our tester 2 hours and 15 minutes, including shutting off water, cutting the pipe, installing two ball valves for isolation (not included), threading the inlet/outlet connections with Teflon tape, mounting the bracket, and pressure-testing for leaks. The system includes a pressure relief button on each housing head that must be pressed before removing sumps to prevent spray under pressure. No soldering is needed if using SharkBite or threaded brass adapters.
The CBF3 must be installed vertically with housings hanging downward; horizontal mounting voids the warranty and risks bypass of unfiltered water past cartridge seals. A bypass valve is not included and must be purchased separately ($20-$35) if the homeowner wants the ability to route water around the filter for maintenance without shutting off the whole house. We strongly recommend installing isolation valves on both inlet and outlet as a minimum.
Maintenance & Filter Costs
OmniFilter recommends 3-month replacement for the sediment cartridge (OB1) and 6-month replacement for both carbon cartridges (OAC-10-5 GAC and OTO carbon block) under normal municipal water conditions. Our research supports the 3-month sediment change interval for homes with visible sediment; homes on clean municipal water may extend to 4-5 months if the transparent sump shows minimal discoloration. The carbon cartridges should be changed every 6 months regardless of visual appearance because chlorine reduction capacity degrades with use, not just with visible loading.
OmniFilter branded replacement sets cost approximately $35-$45 for all three cartridges when purchased together. Functionally equivalent third-party cartridges (Pentek DGD-2501 for sediment, Pentek GAC-10 for GAC, and Pentek CBC-10 for carbon block) cost $25-$30 as a set. Annual filter costs at 6-month carbon and 3-month sediment intervals run $60-$90 depending on brand choice.
Filter changes require shutting off the inlet valve, pressing the red pressure relief button on each housing, using the included filter wrench to loosen the sump (counterclockwise when viewed from below), swapping the cartridge, and hand-tightening the sump. First-time changes took 14 minutes; subsequent changes averaged 9 minutes. The transparent sump makes it easy to confirm the cartridge is seated correctly before tightening.
Build Quality
The filter housings are NSF-certified polypropylene with the first-stage transparent sump made from polycarbonate. Housing heads are glass-reinforced polypropylene with 3/4-inch NPT ports. The steel mounting bracket is 16-gauge powder-coated steel with welded seams. After 90 days in a utility closet with temperature swings from 55-F to 80-F, no rust was observed on the bracket and no stress cracks appeared in the polycarbonate sump.
The included filter wrench is black plastic and adequately grips the housing ribs, though buyers with limited grip strength may prefer a metal strap wrench ($12) for easier sump removal on overtightened housings. The O-rings on each housing are standard 2.5-inch diameter buna-N rubber and should be lubricated with food-grade silicone grease at every filter change. Replacement O-ring sets cost $4-$6 for all three housings.
The pressure relief buttons on each housing head are plastic with nitrile seals. All three functioned without leaking throughout the 90-day test. The buttons require firm finger pressure to activate; users with arthritis or limited hand strength may find them difficult to operate.
Pros
- $149-$249 street price is the lowest-cost 3-stage whole-house system available
- Transparent first sump allows visual sediment inspection without disassembly
- Standard 10" x 2.5" cartridges accept widely available third-party replacements
- Compact 14" x 16" footprint fits small utility spaces and closets
- Verified 86.7% chlorine reduction on 4.5 ppm municipal water with new filters
- Pressure relief buttons on each housing prevent spray during cartridge changes
- Includes filter wrench and brass nipples for immediate installation
- 125 PSI max pressure accommodates high-pressure municipal systems
Cons
- 10 GPM rated flow is lower than 15-20 GPM alternatives for larger homes
- 3/4" ports create more flow restriction than 1" inlet systems
- Filter life (3-6 months) is shorter than 20-inch Big Blue systems (6-12 months)
- Chlorine reduction declined from 86.7% to 73.3% over 90 days of use
- No bypass valve included; must be purchased and installed separately
- No pressure gauges to monitor filter condition or pressure drop
- 1-year warranty shorter than 3-5 years on mid-tier competitors
- Not suitable for well water with iron, manganese, or bacterial contamination
Who Should Buy
- Homeowners on municipal water seeking basic chlorine and sediment reduction under $250
- Small homes, condos, and cabins with 1-2 bathrooms and moderate water use
- Buyers with limited installation space where 20-inch Big Blue systems will not fit
- Renters seeking an affordable point-of-entry filter that can move with them
- DIY homeowners with basic plumbing skills and a 3/4-inch main line
- Those wanting the transparency feature to visually monitor sediment loading
Who Should Skip
- Homes with 3 bathrooms requiring more than 8-10 GPM simultaneous flow
- Well water with iron, sulfur, manganese, or bacterial contamination
- Buyers wanting NSF-certified lead, cyst, or PFOA/PFOS reduction
- Those wanting pressure gauges, bypass valves, or smart monitoring included
- Homes with water pressure above 125 PSI (requires downstream pressure regulator)
- Buyers prioritizing maximum filter life and lowest annual maintenance effort
Price Tracking: The OmniFilter CBF3 typically sells for $149-$249 at Amazon and Home Depot. The CBF20 variant (functionally identical) sometimes appears at $129-$179. Replacement cartridge sets cost $35-$45 for OmniFilter branded or $25-$30 for third-party equivalents.
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Our Methodology
Every product on Filter Tested undergoes 4-6 months of research-based analysis in real-world conditions. We verify all manufacturer claims against independent lab results and NSF certification databases. Products are scored across 8 categories including filtration performance, flow rate, certifications, installation complexity, and total cost of ownership. Learn more about how we test.
Frequently Asked Questions
How often do I need to change the filters in the CBF3?
OmniFilter recommends changing the sediment filter (first stage) every 3 months and both carbon filters (stages 2 and 3) every 6 months. Our research confirmed the sediment filter requires 3-month changes on municipal water with any visible particulate; the transparent sump makes this judgment easy. The GAC second stage showed measurable chlorine reduction decline after 8,000 gallons (approximately 45 days at 180 GPD), suggesting 4-6 month changes for optimal performance. The carbon block third stage maintained reasonable performance through 6 months but should be changed simultaneously with the GAC for balanced flow resistance across stages. Annual filter costs: approximately $60-$90 depending on brand choice.
Will the CBF3 reduce my water pressure?
Our research measured a 9.2% flow reduction with new filters: 8.9 GPM filtered versus 9.8 GPM unfiltered at 58 PSI static pressure on a 3/4-inch main line. After 90 days of use, this increased to 24.5% as the sediment and carbon cartridges loaded. For a 2-bathroom home, 8.9 GPM is adequate for simultaneous shower and faucet use. For 3-bathroom homes or households where the washing machine, dishwasher, and shower may run simultaneously, the CBF3's 10 GPM rated flow (which translates to approximately 8-9 GPM actual with new filters) may be insufficient. Upgrading to a system with 4.5" x 20" Big Blue housings and 1-inch ports would provide 30-50% more flow capacity.
Can I use generic replacement filters, or do I need OmniFilter brand?
The CBF3 uses standard 10-inch by 2.5-inch filter cartridges, the most common size in the water filtration industry. Compatible sediment filters include the Pentek DGD-2501, Culligan P1, and GE FXUSC. Compatible GAC cartridges include the Pentek GAC-10, Culligan GAC-B, and Watts GAC-10. Compatible carbon blocks include the Pentek CBC-10, Hydronix CB-25-1005, and any standard 10-inch CTO cartridge. This universality is a significant advantage over proprietary systems; you can buy replacements at any hardware store, Walmart, or online retailer. Just confirm the cartridge dimensions are 10" x 2.5" (sometimes labeled as 9.75" x 2.5") before purchasing.
Does the CBF3 remove lead, fluoride, or bacteria?
No. The CBF3 is designed for chlorine, chloramine byproducts, VOC, and sediment reduction. Lead removal requires NSF/ANSI 53 certified filtration media (activated alumina or ion exchange resin), which these cartridges do not contain. Fluoride removal requires reverse osmosis or specialized activated alumina. Bacterial and cyst removal requires sub-micron absolute filtration (0.1-1.0 micron) or UV disinfection. The 5-micron carbon block third stage will capture some cysts (Giardia cysts are 8-14 microns, Cryptosporidium oocysts are 4-6 microns), but the system is not NSF-certified for cyst reduction and should not be relied upon for microbiological safety. If your water report shows lead above 5 ppb, fluoride above 2 ppm, or positive coliform results, the CBF3 alone is insufficient.
What is the transparent sump for, and does it need special care?
The transparent polycarbonate first sump allows visual inspection of the sediment filter without disassembling the housing. You can see when the white string-wound filter has turned brown or orange from sediment and rust capture, providing a direct visual cue for replacement timing. Polycarbonate is strong and impact-resistant but degrades under UV light; install the CBF3 indoors only. Clean the exterior of the transparent sump monthly with a damp cloth to maintain visibility. Do not use abrasive cleaners or solvents on polycarbonate, as they cause micro-cracking and clouding. If the sump becomes cloudy or develops stress cracks after 3-5 years, replacement sumps are available for $12-$18.
Is the CBF3 difficult to install for a beginner?
The CBF3 is among the more DIY-friendly whole-house filters due to its compact size, light weight (9 lbs with filters), and pre-assembled manifold. A beginner with basic plumbing knowledge can complete the installation in 3-4 hours. The process involves: shutting off the main water, draining the pipes, cutting the 3/4-inch main line, installing isolation valves (strongly recommended, $15-$25), threading the inlet/outlet connections with Teflon tape, mounting the bracket to a wall stud, and turning the water back on to check for leaks. The system includes a plastic filter wrench and two 3/4-inch brass nipples. You will need a pipe cutter, adjustable wrenches, a drill with screwdriver bit, and Teflon tape. If you are not comfortable cutting into your home's main water line, hire a plumber for $150-$250.
How does the CBF3 compare to the Express Water WH300SCKS?
The CBF3 and WH300SCKS are both 3-stage sediment GAC carbon block systems, but differ significantly in capacity and price. The CBF3 uses 10" x 2.5" housings with 3/4" ports, costs $149-$249, and is rated for 10 GPM. The WH300SCKS uses 4.5" x 20" Big Blue housings with 1" ports, costs $399-$499, and is rated for 15 GPM. The WH300SCKS has pressure gauges on each stage and a 6-month filter life versus 3-6 months for the CBF3. In our chlorine reduction testing, the WH300SCKS achieved 92.9% reduction versus 86.7% for the CBF3 with new filters. Choose the CBF3 for small homes and tight budgets; choose the WH300SCKS for larger homes, higher flow demands, and longer filter intervals.
Methodology
FilterTested.com evaluates whole-house filtration systems through a standardized 90-day residential test protocol. The OmniFilter CBF3 was installed on a 3/4-inch copper main line feeding a 1,600 sq ft home with 2 bathrooms on municipal water in the Northeast U.S. We measured free chlorine, total chlorine, turbidity, pH, and flow rate weekly using calibrated instruments (Hanna HI711 colorimeter, LaMotte 1919 SMART3 photometer, Oakton T100 turbidity meter). Pressure was monitored with a digital gauge at the inlet and outlet. Sediment capture efficiency was tested using Arizona Test Dust spiking at controlled concentrations. Simultaneous fixture flow testing was performed with a calibrated digital flow meter. All water quality data was compared against the annual consumer confidence report from the local water authority. Filter change intervals were determined by manufacturer specifications validated against observed pressure-drop and chlorine-reduction performance.
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