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Natural Waterscapes

Granular Bentonite for Pond Sealing - 3,000 lb Bulk Sack

Ships Via Standard Truck Freight

Bulk discount rates

Below are the available bulk discount rates for each individual item when you purchase a certain amount

Buy 8 - 14 and pay only $1,111.98 each
Buy 15 or above and pay only $846.34 each
  • Sodium Bentonite Clay in Bulk Sack
  • Bentonite application rate for pond lining
  • Sodium Bentonite clay swells in contact with water
  • Bulk bentonite clay for pond sealing
  • Full tractor trailer load of sodium bentonite clay - 22.5 Tons
  • 1.5 tons bentonite clay per bulk sack
  • -3/8 mesh sodium bentonite clay for pond seal
  • Minus 3/8 mesh yields both granular and powdered clay for best pond seal


Natural Wyoming Granular Sodium Bentonite Clay for sealing pond soils

One 3,000 lb sack = 42 cubic feet = 1.56 cubic yards

Bentonite is packaged in bulk sacks with a bottom drawstring port and four lifting loops at the top of the sack.  Less than truck load quantities that ship via enclosed van are palletized.  Full truck load quantities may ship via flatbed freight without pallets.  All bulk sacks have top lifting loops which slide over pallet forks for safe, stable handling.

Full Truck Load of granular bentonite = 15 - 3,000lb sacks = 45,000 pounds 

Bentonite is a natural expanding clay sealant that when exposed to moisture can expand 15X or more creating a very effective pond sealant when applied correctly.


Bentonite for Pond Sealing FAQ

Sodium Bentonite Source

Our bentonite clay is shipped directly from the mine in Northeastern Wyoming.

Bentonite Clay Application Rates for pond/lake bottoms

To properly apply bentonite to seal a pond, the pond must be drained and the bentonite clay then incorporated into the soil of the pond bottom and sides. The application rate for bentonite ranges from 2 pounds to more than 5 pounds per square foot depending on the soil characteristics. For clayey and silty soils, 2 pounds per square foot MAY be sufficient. For sandy soils 4 pounds MAY be sufficient and for soil containing gravel and rock, in excess of 5 pounds will be required to obtain a seal. Once the bentonite is applied, the soil should be disk harrowed to mix the soil and bentonite and then compacted.

Alternatively, a continuous blanket of bentonite can be applied to the soil and then carefully covered with clean soil or sand to prevent the clay from mobilizing into the water column. Placing the bentonite in a confined layer is far more effective as it forces the clay into adjacent soil pores creating a more effective seal.

Detailed Sodium Bentonite Application Instructions

For best results test application rates with your soils by treating a small area at the anticipated application rate.  Drive a 12" or larger diameter smooth wall pipe at least 8" into the soil column.  Manually compact the soil within the pipe and fill with 18" or more of water.  Measure the rate of decline in the pipe and adjust application rate for your soils as needed.  45 lb pails of sodium bentonite are available for testing application rates or treating small areas.

Pond or Lake Dam Repair with Bentonite

For a leaking embankment, if the location of the leak has been identified, it may be possible to construct a core trench in the embankment to slow the leak. To install a core trench, excavate a minimum 12 inch wide trench to at least 3 feet below the pond bottom elevation. The trench should be located as far back from the pond edge as possible while still remaining on the flat top of the embankment.

The goal is to create an impervious core in the embankment which will not allow water to pass through. This impervious core can be created in a number of ways. Bentonite can be mixed with the excavated soil at a rate of 30% bentonite and 70% native soil. The material should be placed back inthe trench and compacted with a trench roller, plate tamper, or excavator bucket in 6 inch lifts. 

Free Standard Freight shipping to lower 48 states.

Lift gate service is unavailable for 3,000 lb sacks- Unloading equipment needed at delivery site. If lift gate is required, 2,000 lb bulk sacks are available.

Allow 7-10 days for freight carrier delivery.

Bentonite Specifications

Granular Bentonite particle size = -8 Mesh

All bentonite particles will pass through a 0.0937" opening. As with any "minus mesh" screened product, all particles are smaller than the mesh opening. This results in a gradient of particle sizes from the 0.0937" to finer powder that is ideal for blending with soil and compacting. 

Bentonite Swell Index = 30

Bentonite Percent Moisture = 16.6%

Aged Fann 600 = 34.0 (measure of viscosity)

pH = 7.75


Bulk Bentonite Clay Reviews - What our Customers are Saying

Bentonite Bulk Sacks
Review by Larry G. on 10 Nov 2021
Purchased 90,000 pounds at a very reasonable rate . Communication was good throughout purchase and delivery with staff . I would recommend doing business with these people!
Great quality
Review by Torrey G. on 27 Aug 2022
Exactly as described. They were great to work with on shipping and receiving. Product was spectacular and exactly as described
Great product, great customer service 
Review by Karen A. on 27 Oct 2021
We’re so happy with our pond. The product is just as advertised. It came quickly and the support was wonderful!
Great customer service
Review by Shaun H. on 27 Oct 2021
We were new at building ponds. Heather was very helpful in deciding how much Bentonite we needed. Although it was the right amount and applied correctly, the Bentonite was still allowing some water seepage, due to our soil. We followed up with customer service and they recommended Soilfloc. We tried it and it worked perfectly. We now have a beautiful pond that is holding water extremely well. We fully stand behind this company and will use them in the future for our pond needs.
Good sodium bentonite 
Review by Chris W. on 21 Sep 2021
Delivery was chaotic with numerous changes in the delivery date and time, but the bentonite arrived as promised and so far is working well.
Clay Pond Liner - Works as designed
Review by Marc D. on 13 Oct 2021
Mixed with soil to repair a washed-out area at discharge end of natural pond. Worked perfectly.
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