Ultra-Dewatering Bags®

Contain silt, sediment and oil pumped out during dewatering operations

Draining swampy or low-lying areas is a common occurrence in construction.
Unfortunately, pumping out the water from these areas also removes a lot of dirt, silt, mud, and debris along with the water. These contaminants can cause problems if they are simply discharged into a storm drain.
The Ultra-Dewatering Bag provides an economical and effective solution. By pumping water into the bag, silt, dirt, sand and other pollutants are trapped and filtered so only water escapes to the ground below or nearby storm drains.
Key Features:
  • Detains both oil and sediment/silt, offering a combination of benefits not available in alternative dewatering bags.
  • Standard and custom sizes available.
  • Accommodates up to 4" discharge hose.  Optional hose connector available - makes connecting and disconnecting Dewatering Bags quick and easy.

NOTE: To increase the efficiency of filtration, place the bag on an aggregate or haybale bed to maximize water flow through the surface area of the bag. 

  • Helps comply with NPDES, 40 CFR 122.26 (1999) and TMDL requirements.


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Ultra-Dewatering Bag

Part # Dimensions ft. (m) Capacity cu. ft. (L) Weight lbs. (kg) Where to Buy
9729-O/S 3 x 4 (0.9 x 1.2) 12 (340) 2.0 (1.0)
9724-O/S 6 x 6 (1.8 x 1.8) 36 (1,019) 5.0 (2.5)
9723-O/S 8 x 8 (2.4 x 2.4) 64 (1,812) 5.0 (2.5)
9725-O/S 10 x 15 (3.0 x 4.6) 150 (4,247) 21.0 (9.5)
9727-O/S 15 x 15 (4.6 x 4.6) 225 (6,371) 30.0 (14.0)


Part # Description Weight lbs. (kg) Where to Buy
9739 Optional Hose Connector for 4" hoses 2.0 (1.0)

More info / Downloads


Article - What is Dewatering?

DOT Approvals

Arizona Dept. of Transportation - Letter

Misssissippi Dept. of Transportation


Frequently Asked Questions

Is there a way to maximize flow through the bag?
The total flow rate through the Dewatering Bag can be maximized by getting it off the ground.  While water will flow through a Dewatering Bag laying flat on the ground, it will be impeded by the solid/saturated soil it is on.  By placing the bag on large aggregate or on hay bales, the water will be less restricted as it flows through the bottom layer of geotextile fabric.

What is the flow rate?
The maximum flow rate of the Ultra-Dewatering Bags, when new, is 500 gallons/min.  For more information, check out our specifications.

What should I do with the bag when it's full or I’m done dewatering?
When the Dewatering Bag is full, it should be disposed of as directed by the site engineer and in accordance with any local regulations and requirements.  Often times, it can simply be cut open and the contents dispersed.

I need a Dewatering Bag in a size that is not listed.  Can you make that for me?
Yes, we can do custom sizes (and shapes).  Please contact us for a quote.

How do I secure the Dewatering Bag to the discharge hose?
If your flow rate is not too high, you can use the attached straps to tie off the bag to the hose.  If water is being discharged at a higher flow rate, a hose clamp may be required (not included).  You can also use our optional Hose Connector (Part# 9739) to make the connection quick and easy.

  • 40 CFR 122.26