Frequently Asked Questions

Clearbrook filters are independently lab-tested to remove over 99% of more than 365 common contaminants across these categories:

• Heavy metals — lead, copper, mercury, arsenic, cadmium, chromium (hexavalent), aluminum, barium, nickel, selenium, uranium, and 13 more
• PFAS / "forever chemicals" — including PFOA, PFOS, GenX, PFBS, PFNA, PFHxA, and other regulated compounds
• Disinfectants and byproducts — chlorine, chloramine, haloacetic acids (HAAs), trihalomethanes (TTHMs)
• Pharmaceutical residues — acetaminophen, ibuprofen, antibiotics, hormones (estradiol, estrone, testosterone), caffeine, BPA
• Pesticides and herbicides — atrazine, glyphosate, DDT, lindane, chlordane, and over 50 others
• Volatile organic compounds (VOCs) — benzene, vinyl chloride, trichloroethylene, MTBE, and dozens more
• Semi-volatile compounds (SVOCs) — including PCBs, phenols, and polycyclic aromatic hydrocarbons
• Phthalates — plasticizers commonly found in modern water systems
• Microplastics — over 99.99% removal
• Radiological elements — Gross Alpha (Thorium 230) and Gross Beta (Cesium 137)
• Nitrates, nitrites, sulfates, and other inorganic compounds

For the complete contaminant-by-contaminant breakdown with specific removal rates, [view our lab results].

Clearbrook gravity-fed systems use multi-stage filtration through specially engineered filter elements. Pour tap water in the upper chamber; gravity pulls it through the filter elements into the lower chamber. The filter elements physically block, chemically adsorb, and ion-exchange contaminants out of the water — leaving the natural minerals your body needs while removing what shouldn't be there. No electricity, no chemicals, no pumps required.

Yes — by independent third-party labs, not in-house. We don't make a claim we can't back up with data. [View the test results here.]

Yes. PFAS and PFOS are persistent industrial chemicals that don't break down in nature — or in the human body. Clearbrook gravity-fed systems remove these "forever chemicals" during filtration based on independent third-party testing.

The answer depends on which Clearbrook system you have:

• Under-sink filters (Gen4 and Dual Filter System) are independently tested to remove over 90% of sodium fluoride during normal filtration. If fluoride removal matters to you and you're choosing an under-sink system, you're already covered.
• Gravity-fed countertop systems focus on a broader range of contaminants and don't directly target fluoride at the same level. For households with gravity systems that want fluoride and arsenic removed, we offer the Clearbrook PF-2 Fluoride & Arsenic Reduction Elements — designed to install onto your existing Clearbrook elements. Independent testing shows typical fluoride reduction greater than 95%, and under optimum conditions, greater than 99.75%.

Clearbrook removes contaminants but is not a water softener. Hard water — caused by naturally occurring calcium and magnesium minerals — typically requires a separate softener if you want to address scale buildup in pipes and appliances. The minerals that make water hard aren't harmful to drink; many people actually prefer the taste. Clearbrook will still remove contaminants from hard water; softening is a separate concern.

No. Softened water and salt water can clog the filter pores — and using them will void your warranty. Use the cleanest freshwater source available. If your home has a water softener, use Clearbrook with water taken upstream of the softener.

Our gravity-fed systems are designed for any water source — including well water. Our under-sink filters are designed for municipal tap water and aren't the right choice if your home runs on a well. If you're on well water, choose one of our countertop gravity systems. For unusual conditions — extreme iron, strong sulfur smell, or heavy sediment — [contact us through Clear Answers] and we'll help you build the right setup.

No. Use cold or room-temperature water only. Hot or boiling water can damage the filter elements. Avoid placing the system in direct sunlight or near heat sources like a stove or heater.

The CB9 is our original gravity filter design and the filter we have sold over 3 million of over the last 20+ years. The CB9 measures 9” tall x 2 1/4” wide. It is our classic taller, slimmer filter design.

The CB5 is our second generation gravity filter. It measures 5” tall x 3” wide. The CB5 uses the exact same filtration technology, formulation, and gram weight of filtration media as the CB9.

The main difference between the two filters is the shape and how they perform as the water level drops during filtration. The CB9 is taller and slimmer, so as the upper reservoir water level lowers, the top portion of the filter can become exposed above the water line sooner, which can gradually slow the flow rate.

The CB5, on the other hand, is shorter and wider. Because of this design, it stays fully submerged longer as the water level drops, allowing more of the filter surface area to remain active throughout the filtration cycle. This helps provide a more consistent flow rate from start to finish.

Both filters use the same proven filtration technology the difference is simply the physical design and how each filter interacts with changing water levels during use.

Both deliver clean, lab-tested water — the difference is how you get to it.

Gravity-fed systems sit on your counter. Pour tap water in the top, let gravity pull it through the filter elements, and dispense clean water from the spigot at the bottom. No plumbing, no electricity, no installation. Works on any water source — municipal, well, or surface.

Under-sink systems install on your home's cold water line and deliver filtered water on demand from your tap. Faster flow, no countertop space needed, but designed for municipally treated water only (not well water with iron or sulfur). Both under-sink models require maximum 60 PSI water pressure and cold water only — never connect to hot.

If you want simplicity, portability, and any-water-source capability — go gravity. If you want filtered water at the turn of a tap and you're on city water — go under-sink.

It depends on three things: how much filtered water you use, where you want it, and whether you need power-free operation.

Countertop gravity systems — five sizes from 1.5 to 6 gallons. No plumbing, no electricity required.

• 1.5 Gal — singles, couples, small kitchens
• 2.25 Gal — small families
• 3.25 Gal — mid-size families
• 4.5 Gal — larger households or heavy users
• 6.0 Gal — large families, group homes, community use

Under-sink filters — filtered water on demand from your tap, no countertop space needed.

• Pro DualStage Under-Sink — built for kitchens, where filtration volume is highest
• Gen4 Under-Sink — single-stage system, ideal for bathrooms and lower-volume use

Field Gravity 5 Gal — built for emergencies, missions, and off-grid use. Same gravity-fed technology as our countertop line, in a rugged carry-anywhere design.

Not sure which fits? [Contact us through Clear Answers] — we'll help you pick.

We offer two under-sink options:

Clearbrook Dual Filter System (SF-D12-P) — built for kitchens, where filtration volume is highest. Two-stage filtration with separate replacement schedules:

• Stage 1 (SF-12-F): 1,000 gallons / up to 6 months
• Stage 2 (SF-12-GEN 4): 2,000 gallons / up to 1 year

Clearbrook Gen4 2512 Under-Sink — single-stage system, ideal for bathrooms or lower-volume use. Rated for 2,000 gallons or up to 1 year, with a recommended flow rate of 0.5 GPM. Works with municipal or properly disinfected water at temperatures up to 120°F.

Both systems wall-mount under the sink, install with basic plumbing, and operate on existing water pressure (no electricity required).

A good rule of thumb: pick the size that matches your daily filtered-water use, then size up if you cook, bake, or fill water bottles for a household on the go.

• 1.5 Gal — singles, couples, small kitchens. Daily-use simplicity.
• 2.25 Gal — small families, low-to-moderate water use.
• 3.25 Gal — mid-size families and households that drink and cook with filtered water daily.
• 4.5 Gal — larger households, heavy users, or families that fill bottles for school and work.
• 6.0 Gal — large families, group homes, churches, ministries, or community-style shared use.

When in doubt, size up. A larger system means fewer refills — and you'll never regret extra capacity in an emergency.

Yes — the Clearbrook Field Gravity 5 Gal. Same gravity-fed technology as our countertop systems, in a rugged carry-anywhere build engineered for emergency preparedness, mission camps, RVs, off-grid cabins, and disaster response. No electricity. No plumbing. Just gravity and clean water, wherever you need it.

This is the system Clearbrook has deployed to hurricane response in Puerto Rico and the Bahamas, mission camps in sub-Saharan Africa, and households without grid access. If reliable water is part of your preparedness or mission plan, the Field Gravity System is built for you.

Yes — our countertop gravity systems require no plumbing, no installation, and no permanent fixtures. Pour water in, drink from the spigot. Pack it up when you move. They're ideal for renters, dorms, RVs, or anyone who doesn't want to (or can't) drill into a counter or modify the home water line.

If you specifically want filtered water at your tap and you're a renter, talk to your landlord first — most under-sink systems can be uninstalled without permanent damage, but you'd need permission to install one in a rental kitchen.

No. Our gravity-fed systems use gravity to pull water through the filter elements — no power, no plumbing, no pumps. That's part of why Clearbrook works equally well on a kitchen counter, in a power outage, or at a mission camp where there's no grid.

After priming and assembly, water begins dripping into the lower chamber within about 15 minutes. The system reaches its maximum flow rate after the first 12 to 24 hours of use. Discard the first 1 to 2 batches as a normal flush — new filter elements may produce slightly cloudy or off-tasting water until the carbon settles in.

For under-sink systems: filtered water is available immediately after installation, though we recommend running 1 to 2 gallons through the system before drinking, to flush out any manufacturing residue.

Yes — priming is essential. Without priming, the gravity system will not work. There are two priming methods:

• Method 1: Tan Priming Button (included). Hold the included tan priming button against your faucet, press the filter nozzle into the button opening, and run water through the filter until the entire surface is covered in beads — that means the filter is saturated.
• Method 2: Clearbrook Primer™ Pump (sold separately). Faster and more thorough for households with multiple systems or frequent filter changes.

Each set of Clearbrook gravity-fed elements is rated for up to 3,000 gallons — years of clean water from a single replacement. Actual lifespan depends on water source and household use:

• Light use (1–2 people): 2 to 3 years per set
• Medium use (3–4 people): 1 to 2 years per set
• Heavy use (5+ people): 10 to 12 months per set

Heavily contaminated source water (well or surface) shortens lifespan further.

We recommend a full cleaning every 30 days:

1. Lower chamber and spigot: Clean with mild dish soap or a 1:1 mix of water and white vinegar. Rinse thoroughly. Do not use bleach or harsh detergents.
2. Spigot: Soak in 1:1 water-vinegar for 5 to 10 minutes to remove mineral deposits.
3. Filter elements: Use a soft toothbrush to gently brush the outside of the filters under cold running water to remove accumulated debris.

Three signs your filter elements are reaching end of life:

1. Filtration time slows dramatically, even after re-priming and a thorough cleaning.
2. You've reached the rated gallon count (up to 3,000 gallons per set).
3. Taste or odor changes — if filtered water starts to taste like the source, the carbon is exhausted.

When in doubt, replace.

Storage protocol depends on how long you'll be away:

• Short trips (4 to 15 days): Remove the filter elements while still damp. Place them in a sealable plastic bag (gallon-size or larger) to keep them wet, and store the bag in your refrigerator. Do not freeze. When you return, rinse the elements under cold water before reinstalling.
• Longer absences (15+ days): Remove and shake off excess water. Air-dry the elements on a windowsill or sunny location for 1 to 3 days until completely bone-dry. Store in a sealable plastic bag at room temperature.
• Reactivating dried elements: Scrub the outside under cold running water with a stiff brush or Scotch-Brite® pad, then re-prime before reinstalling.

Important: Never let wet Clearbrook filter elements freeze — freezing damages the elements and voids your warranty.

Yes. Every Clearbrook filter is American-made — designed, formulated, and produced in the United States. We've been doing it for over 30 years. As an American company, we believe quality and accountability start with where — and by whom — products are built.

For more than 30 years. Clearbrook has been manufacturing gravity-fed water filtration systems in the United States since the early 1990s — supplying families, communities, and mission teams around the world with clean, safe drinking water that doesn't depend on electricity, chemicals, or bottled alternatives.

For more than 30 years, Clearbrook has been the manufacturer behind some of the most recognized gravity-fed water filters on the market — including the filter sold under the Black Berkey trade name (known as the BB9). We made the filter; the brand on the box was someone else's.

We no longer supply that trade name, though we continue manufacturing for select industry partners. What's new is that for the first time, we're also selling directly to you, under the Clearbrook name. The filter you knew as the BB9 has evolved into the Clearbrook CB9 — built in the same American facility by the same hands, with the same independent lab testing, but refined over years of work to outperform the original. The name on the box has changed. The standard just got higher.

[For more on Clearbrook's history and our decision to go direct, visit our blog.]

Clearbrook, LLC is headquartered in Mobile, Alabama. Every filter we make is designed, formulated, and produced in the United States.

Three things:

1. 30+ years of American manufacturing. We're not a recent startup. We've been formulating and producing gravity-fed water filters in the USA since the early 1990s — including the filters sold under some of the most recognized brand names in the industry.
2. Independent third-party lab testing verified across more than 365 contaminants — including heavy metals, PFAS, microplastics, pesticides, pharmaceutical residues, and disinfectant byproducts. Real data, not marketing claims.
3. Mission and integrity behind every filter. Clearbrook is family-led, guided by faith, and committed to using its work to put clean water into the hands of communities in crisis. Every purchase you make supports that.

Every Clearbrook product comes with a 30-Day Satisfaction Guarantee. If you're not completely satisfied for any reason, you can return or exchange your item for a refund within 30 days of purchase.

A few things to know before you ship it back:

• Return shipping is the customer's responsibility and is deducted from the refund amount.
• Products showing signs of improper use or damage may not qualify.
• Proof of purchase is required.
• Only purchases made directly at clearbrookfilters.com are eligible. (For purchases from authorized dealers, follow that retailer's return policy.)
• Used filter elements cannot be returned.

To start a return or exchange, email hello@clearbrookfilters.com or call our support team at (251) 656-2117, Monday–Friday, 9 AM to 4 PM Central.

Yes — every Clearbrook product is covered by a 1-Year Limited Warranty against defects in workmanship and materials. Your remedy under the warranty is repair or replacement.

The warranty does not cover:

• Normal wear and tear
• Misuse, improper installation, or unauthorized modifications
• Damage from extreme temperatures, chemicals, or pressure beyond design limits
• Damage from freezing, neglect, or non-standard water systems

Performance variations — flow rate, taste, and filter lifespan can vary based on your water quality and use, and aren't guaranteed under the warranty.

To file a claim, email hello@clearbrookfilters.com with your proof of purchase and a brief description of the issue. We may request photos or ask that the product be returned for inspection before determining eligibility.

Yes — we welcome inquiries from churches, mission organizations, schools, disaster-relief groups, and anyone looking to order multiple Clearbrook systems for community or organizational use. Whether you're equipping a mission team, stocking a community resource center, or coordinating disaster preparedness, we'd love to talk through what you need.

Email us at hello@clearbrookfilters.com with your group, the kind of work you're doing, and roughly how many systems you're considering. A real person will respond and connect you with the right next step. We're a small team, and we treat every conversation like a relationship, not a transaction.