PW OBJ K Gravity Water Filter Review: Filters 99.99% of Tiny Materials With a 0.01 Micron UF Membrane

What the PW OBJ K Is, and Who For

PW OBJ K Gravity Water Filter filters with 0.01 microns for you if you need finer pore size for suspended particles.

If your counter setup needs stainless steel and you want a gravity filter with a stated hourly output, the material and flow figures matter before anything else. A 4 gallon/hour rate makes the pace part of the purchase, not an afterthought.

PW OBJ K Gravity Water Filter matches that situation with 304 food-grade stainless steel housing and a 4 gallon/hour flow rate. PW OBJ K also lists a 0.01 micron filter pore size, which is the other number that shapes who should buy it. The listing further states NSF/ANSI 42 certification and NSF/ANSI 372 certification.

We screened 28 Gravity Water Filters and this is one of 15 chosen for a full review. Full reviews go to the most-rated products that pass screening, at most 2 per brand. This one has 1,472 buyer ratings, the 1st most of the 28 screened. This review is for you if you are deciding between material, flow, and pore size first.

If you need a different capacity, browse our full Purewell 2.25G Filter review.

The Short Answer on the PW OBJ K

Best for: you need a gravity water filter with fine particle capture and a 4-gallon-per-hour output for everyday countertop use.

PW OBJ K is the right pick at around $149 if you want 0.01-micron filtration and a stainless steel build.

• Pro: The 0.01-micron pore size gives you very fine filtration for a countertop gravity filter.
• Pro: Its 4 gallons per hour flow rate helps keep refills moving at a practical pace.
• Pro: The 6000-gallon filter life reduces how often you need replacement elements.
• Con: A 4 gallons per hour output is not fast, so larger households may wait longer for a full lower chamber.
• Con: The listing states two filters, which gives less redundancy than six-filter systems for buyers who want extra capacity per set.

Don’t buy this if: you need a countertop gravity filter that stores 2.25 gallons or more in one batch, because the listed capacity is not stated here.

Price assessment: Around $149 is fair for 0.01-micron filtration, stainless steel construction, and a 6000-gallon filter life.

This purchase can cost you time if your household needs a larger batch size than this listing states.

For those preparing for disasters, look at the best gravity water filter for emergency preparedness.

The Numbers on the Spec Sheet

Filter pore size separates this PW OBJ K most clearly from the other deciding specs. It measures the size of the openings in the filter, which limits what particles can pass through.

Before You Buy: Gravity Water Filter Checklist

The first thing to check is the flow rate, because 4 gallons per hour is what decides whether this gravity filter keeps up with your daily use or leaves you waiting.

• ☐ Confirm the flow rate — 4 gallons per hour; if you need faster dispensing, you will live with slow fills and an upper chamber that can sit full for hours.
• ☐ Check the filtration level — 0.01 microns; if you want a different pore size, you will need a different gravity water filter and may end up keeping contaminants you expected to reduce.
• ☐ Measure your placement space — 304 food-grade stainless-steel housing with a stand included; if your counter setup is tight, you may have to rearrange the area or choose a smaller unit.
• ☐ Confirm the contaminant claims you need — NSF/ANSI 42 certified black carbon filter and NSF/ANSI 372 certified; if you need a reduction claim that is not stated here, you should not buy this model for that job.
• ☐ Budget for the capacity style you want — two filters with a 6,000-gallon filter life; if you need a larger or longer-lasting setup, you may end up replacing the elements sooner than planned.
• ☐ Check the included hardware — faucet included and stainless steel spigot material; if you expected a different faucet setup, you will have to modify your plan after delivery.

If you need a faster output than 4 gallons per hour or you need a reduction claim that is not stated here, do not buy this gravity filter.

What performance means in practical terms

How 3-stage filtration handles chlorine, rust, and sediment

PW OBJ K’s 3-stage filtration gives you one unit that handles chlorine, rust, sediment, and organic matter in a single countertop setup. The black carbon filter is NSF/ANSI 42 certified, so the chlorine, taste, and odor claim has a standard behind it. The listing also names a silver ion membrane and an activated carbon block, and the result is a filter set aimed at everyday tap-water cleanup rather than one narrow contaminant.

The 4 gallons-per-hour flow rate is the number that matters for daily use. That pace can support a household that draws water through the day, but it will feel slower if several people try to fill bottles at once. If your family drinks from the same unit all day, count how many liters you want ready before refilling; a higher draw rate favors heavier use, while lighter use leaves more margin. The 6000-gallon filter life also means fewer changeouts than short-life systems, so the maintenance load stays lower over time.

What fine-pore membrane protection means for tiny materials

PW OBJ K’s 0.01 micron filter pore size is the figure that tells you how small the openings are. That size is aimed at tiny materials, and the listing says the system filters 99.99% of them. For buyers worried about fine particles, that is the number that matters more than the marketing around the membrane stack.

The hollow fiber UF membrane and the NSF/ANSI 372 certification add two different kinds of value. UF, or ultrafiltration, is the kind of membrane buyers choose when they want tighter particle control in a gravity filter, while NSF/ANSI 372 addresses lead-content compliance in the materials. If you want protection against very small suspended material, this is the section of the spec sheet that supports that goal; if you only need basic taste improvement, the finer pore size is more than you need.

Why 304 stainless steel housing matters in a gravity filter

PW OBJ K uses 304 food-grade stainless steel housing, and that material choice is the main reason it belongs in a gravity water filter discussion. Stainless steel is common in this category, and this listing joins the larger group of metal-bodied countertop units rather than the smaller set that use other materials. The metallic water level spigot and included stand also point to a fixed countertop setup instead of a portable jug.

The stainless-steel body favors buyers who want a sturdier-feeling countertop system with a 2-filter layout, not a lightweight plastic tank. The stand and faucet included in the package reduce the number of separate parts you need to source, which matters if you want a ready-to-place gravity filter rather than a pieced-together setup. If you are choosing between capacity and footprint, this listing does not state tank size, so the housing and fittings are the clearer decision points here.

Where the PW OBJ K Sits Among the Alternatives

PW OBJ K’s clearest edge is its 0.01-micron filter pore size and 4 gallons per hour flow rate. That combination gives you fine filtration with a stated output rate that is faster than the 0.01-micron KST-XYB101 and more aggressive than the 0.2-micron FACHIOO.

• Against AquaEasy LE, the PW OBJ K uses 0.01-micron filtration, while AquaEasy LE only states coconut shell activated carbon. That makes the Purewell the more specific pick when pore size matters more than a general carbon media callout.
• Against MSR AutoFlow, the Purewell states NSF/ANSI 42 certification for its black carbon filter and NSF/ANSI 372 certification for materials. MSR AutoFlow does not state either standard in the data here.
• Against Gravity-Fed Water Filter System, PW OBJ K gives a 4 gallons per hour flow rate. The competitor only states 3-gallon capacity, so this comparison favors output speed over stored volume.
• Against FACHIOO 2.25G Stainless Steel 304, PW OBJ K has the smaller pore size at 0.01 microns versus 0.2 microns. That is the sharper filtration claim in this pair.
• Against KST-XYB101 1G Gravity-fed Water Filter, PW OBJ K is the pricier option at around $149 versus $119.99. The KST unit is the cheaper buy if price matters more than the Purewell’s 0.01-micron rating.

If you want the lower-cost route, pick KST-XYB101 1G Gravity-fed Water Filter instead. It is the cheapest of the six, and the price gap is large enough to matter for a budget-first purchase.

You can find our full review of the Purewell K8627 to see how it handles larger volumes.

For a more compact option, see how the K8675 performs in our review.

What It Takes to Run the PW OBJ K

What this countertop gravity filter needs before first use

PW OBJ K needs a clean surface and the two stainless steel filters already fitted before it can produce filtered water.

1. Unpack the stainless steel housing and confirm that the 2 filters are present.
2. Install the black carbon filter and the 0.01m hollow fiber UF membrane in their assigned positions.
3. Prime the filter elements if they need it, using the priming washer matched to the filter opening.
4. Seat the metallic water level spigot and its gasket so the outlet closes without leakage.
5. Fill the upper chamber and wait for the flow rate of 4 gallons per hour to begin dispensing.

Warranty and support: what to check for this Gravity Water Filter

Warranty cover differs by seller and country.

• Confirm the return window before you fill the chambers, because the 0.01 micron filter pore size and sealed stainless steel parts are not user-serviceable.
• Confirm whether replacement filter elements are available, because the listed 6,000-gallon filter life means you will eventually need them.
• Confirm that the spigot gasket is covered or easy to replace, because the stainless steel outlet depends on a tight seal.
• Confirm whether a fluoride filter element is supported, because that specialized reduction stage is not listed among the included parts.

On the day it arrives, inspect the filters, spigot gasket, and outlet fit while a return is still possible.

Questions Buyers Ask About This Gravity Filter

Is PW OBJ K worth around $149, or are you paying extra for the stainless housing and filter stack?

Yes, if you want a gravity water filter with a 0.01-micron pore size and a 4-gallon-per-hour flow rate. PW OBJ K also states 304 food-grade stainless-steel housing, two filters, and a 6,000-gallon filter life, so the price is not only about the metal shell. The stainless housing is part of the build, but the filtration figures are what separate this listing from simpler countertop gravity filters.

Does PW OBJ K use NSF-certified filtration?

PW OBJ K states NSF/ANSI 42 certification for the black carbon filter and NSF/ANSI 372 certification for the system. NSF/ANSI 42 covers chlorine, taste, and odor claims, while NSF/ANSI 372 addresses lead-content compliance in materials. The listing also says the filter reduces chlorine and intercepts rust, sediment, organic matter, and heavy metals.

How much water does PW OBJ K filter in an hour?

PW OBJ K is listed at 4 gallons per hour. That rate matters if you want a countertop gravity filter that does not leave you waiting long for a refill cycle to finish. It is a flow figure, so it tells you throughput, not storage size or pore size.

What does the 0.01-micron filter pore size mean for PW OBJ K?

The 0.01-micron filter pore size means PW OBJ K is built around very fine filtration. In this category, smaller pore sizes are the figure buyers watch when they want tighter particle reduction from a gravity-fed water filter. The listing also says the system filters 99.99% of tiny materials, but the pore size is the hard spec that frames that claim.

Is the PW OBJ K Right for You?

Who the PW OBJ K suits and the jobs it is the wrong choice for, listed below with the reason for each.

Where to Buy This Countertop Gravity Filter

Gravity water filters are sold by the retailers below – we do not track which of them has the PW OBJ K in stock, so check availability and the current price with the retailer before making a trip.

• Bass Pro Shops (online and physical stores) — specialist staff for camping and emergency water filtration
• The Berkey Store (online only) — specialist retailer for gravity water filters
• Amazon (online only) — breadth of range
• Walmart (online and physical stores) — in-store returns
• Target (online and physical stores) — easy local pickup and returns
• Home Depot (online and physical stores) — in-store returns and broad household category coverage
• REI (online and physical stores) — specialist staff and trusted outdoor-water-filter selection

Outdoor enthusiasts can view the best gravity water filter for camping to see how they compare.

Final Verdict on the PW OBJ K

You want a countertop gravity filter with 0.01-micron filtration and a 4-gallon-per-hour flow rate. PW OBJ K is the pick at around $149.

The 0.01-micron pore size is the key number here. It is the fine-opening limit that shapes what can pass through, while the 4-gallon-per-hour output keeps the lower chamber moving without turning this into a slow pour-and-wait setup.

Skip it if: you need a larger batch size than a 4-gallon-per-hour unit suits, or you want a model with a stated capacity figure for fewer refills.