Wesnoy 2 Pcs Silt Bags for Dewatering Filter Bag Non Woven Geotextile Fabric Oil Sludge Sediment Filter Bags for Construction, Black

Why I picked up these silt bags

After a week of heavy rain, I needed a straightforward way to knock down turbidity in pumped runoff without building a whole sediment basin. The Wesnoy silt bags looked like a practical, low-fuss option: non-woven geotextile, a generous 5 x 10 ft footprint, and a two-pack so I could swap or run in parallel. On paper, they accommodate up to a 4-inch discharge hose, and that’s right in the range for most jobsite pumps I carry. I tested them on a mix of tasks—draining a muddy excavation, dewatering a flooded landscaping area, and polishing water from a small sump with light oil sheen.

Below is how they fared, what setup details mattered, and where I’d use them again.

Build and design

The bags arrive folded and compact. The geotextile is a non-woven black fabric with a medium hand—pliable enough to lay flat and conform to ground contour, but not flimsy. The size is the headliner: at 5 x 10 ft, you get meaningful surface area for filtration and flow diffusion. Seams feel decent to the touch, but like most dewatering bags, they’re also the stress point if you let the bag balloon.

There’s an inlet sized to accept up to a 4-inch discharge hose. There’s no rope or cinch hardware included, so plan on hose clamps, cam straps, or heavy zip ties to secure your line. I set mine up on a tarp and a layer of sand to avoid abrasion from gravel and to spread load.

Setup tips that made a difference

• Support the bag: Lay it on a smooth tarp or plywood and keep it off sharp rock. A thin bed of sand or mulch helps.
• Diffuse the flow: Don’t feed the inlet straight from a high-output pump at full throttle. Use a valve or restrictor if your pump doesn’t have one.
• Secure the inlet: Double-strap the hose connection and tape over sharp clamp tails to avoid punctures.
• Give it room: The bag needs space to spread out. Don’t wedge it against a wall or curb where it can’t expand.
• Plan your rotation: With two bags, you can swap when one loads up with fines or run them in parallel if your flow requires it.

These are simple steps, but they directly affect durability and throughput.

Performance on the ground

With a 2-inch submersible pump moving sediment-laden water from an excavation, the bag performed well. The discharge started murky, then cleared out as the fabric wetted and fines began to cake into a filter layer. Outflow clarified to a level I was comfortable releasing onto vegetated ground without chasing muddy plumes. Flow remained steady, with manageable backpressure.

I also used the bag as a polishing step for water that had a light oil sheen after equipment had been parked in the area. Non-woven geotextile can adsorb some hydrocarbons, and I did see a reduction in sheen, but this isn’t an oil-only filter. If you need compliance-grade oil capture, add an oil-absorbing boom at the inlet or use a specialized cartridge.

On sandier runoff, throughput was strong. On clay-heavy water, the bag clogged faster, which is expected—fine clays blind non-woven fabric quickly. As the bag loads up with fines, the discharge rate drops; having two bags makes it easy to rotate and let one drain down.

High-flow realities and durability

I pushed the limits with a 3-inch trash pump at idle. Within half an hour, the bag inflated more than I liked and developed a split near a seam. That’s on me for not diffusing the flow enough—the combination of high instantaneous velocity, head pressure inside the bag, and a hard spot under the seam is a recipe for a tear in any dewatering bag of this class.

I adjusted setup: throttled the pump, used a wye to split into both bags, set them on a cushioned base, and staked the corners to spread the load. With those changes, I ran similar flows without further issues. The takeaway: these bags are well-suited to modest, controlled flows. If you intend to run a high-output trash pump continuously, you either need to split the flow across multiple bags or step up to a heavier-duty, reinforced bag or a larger geotextile tube.

Capacity and maintenance

• Size and throughput: The 5 x 10 ft size is generous for temporary dewatering. Comfortably, I’d run a 2-inch line or a throttled 3-inch line. For faster flows, plan on two in parallel.
• Clogging behavior: Expect quicker blinding with fine silts and clays. A pre-settling tote, hay bales, or a gravel check upstream can extend bag life and maintain discharge rates.
• Handling and disposal: Once loaded, the bag gets heavy. Let it drain, then shovel out solids or cut the bag and dispose per your site’s waste plan. Don’t drag a loaded bag across abrasive ground.

Where these shine

• Small to mid-size dewatering tasks where you need to knock down turbidity fast.
• Construction punch-list work, utility tie-ins, and landscaping jobs where deploying a full sediment basin is overkill.
• Temporary SWPPP measures when you need a documented best management practice to supplement other controls.
• Home and facility use for pond maintenance or sump discharge, especially when you can throttle the pump.

Where I’d choose something else

• Continuous high-flow dewatering with a 3- or 4-inch trash pump running near capacity. Use reinforced, woven bags or larger geotextile tubes designed for higher internal pressures.
• Heavy debris streams with sticks/aggregate. Pre-screen or settle first to avoid tears and premature clogging.
• Projects requiring certified oil-only capture. Add oil absorbents or use a dedicated oil/water filtration unit.

Value

The two-pack is practical. It lets you scale up by running parallel lines or keep a spare for rotation. For contractors and facility teams, that flexibility matters more than shaving a few dollars on a single bag. The materials and size are competitive for this class. The caveat is durability under aggressive flows; plan around that, and the value proposition holds up well.

What I’d improve

• Reinforced seams or an added wear patch on the inlet side would buy more margin for error with inexperienced crews.
• A simple cinch sleeve or integrated strap at the inlet would speed setup and reduce the chance of a loose connection.
• Including a brief flow/pressure guideline would help users match pumps to the bag without learning the hard way.

Bottom line

Used within its lane, the Wesnoy silt bag is a straightforward, effective dewatering tool. It filters sediment and fines reliably, helps you present a cleaner site, and gives you options with the two-pack format. It is not a heavy-duty, high-pressure containment bag, and it doesn’t pretend to be. Treat it as a polishing step, manage your flow, give it room to spread out, and it will do the job.

Recommendation: I recommend these silt bags for small to medium dewatering tasks at controlled flow rates. They’re easy to deploy, filter well, and the large footprint helps maintain discharge without excessive backpressure. If your plan is to run a 3-inch or larger trash pump hard and uninterrupted, step up to a reinforced solution or split the flow into multiple bags. With thoughtful setup, these bags earn a spot in the truck.