PondLock™ is a premium-grade Wyoming sodium bentonite clay engineered for pond sealing, dam repair, and water retention. ASTM tested with a Free Swell Index that exceeds NRCS standards by 36%.
PondLock™ is a naturally occurring sodium bentonite clay mined from premium deposits in Northeastern Wyoming. When exposed to water, the clay expands up to 15 times its dry volume, forcing its way into soil pores to form a dense, self-sealing barrier that stops water loss.
Unlike calcium bentonite or chemically treated clays, PondLock™ achieves its sealing properties through naturally high sodium content — no additives required. The result is a permanent, eco-friendly seal that works with your soil, not against it.
Never kiln-dried. Low-temperature processing preserves maximum swell capacity and avoids fossil fuel waste.
Lab-verified Free Swell Index of 30 ml — exceeding the NRCS Conservation Practice Standard 520 threshold of 22 ml.
Safe for fish, livestock, irrigation, and swimming. No synthetic chemicals, polymers, or additives of any kind.
From farm ponds to municipal infrastructure, PondLock™ sodium bentonite provides a proven, natural sealing solution across a wide range of water retention applications.
Seal new pond construction or repair leaking ponds with the blanket method, mixed method, or targeted application. Application rates from 2–6 lbs per square foot based on soil type.
Learn MoreCore trenches, embankment sealing, and leak repair for earthen dams. Bentonite mixed at 30% with native soil creates an impervious core that stops seepage.
Learn MoreCreate low-permeability barriers for landfills, waste lagoons, and containment systems. Sodium bentonite provides a natural, self-healing liner that meets regulatory standards.
Learn MoreBulk sack delivery for large-scale lake sealing projects. PondLock™ ships in 2,000 and 3,000 lb sacks by LTL or full truckload to meet large project requirements.
Learn MoreAgricultural lagoons, wastewater ponds, and treatment facilities. PondLock™ provides a natural, chemical-free liner that protects groundwater while containing process water.
Learn MoreBentonite chips and granular clay for sealing abandoned wells, plugging drill holes, and sealing around pipe penetrations in dams and embankments.
Learn MoreThe quality of sodium bentonite varies dramatically by deposit, processing method, and handling. PondLock™ is sourced from premium Wyoming deposits and processed to preserve maximum performance.
Our Free Swell Index of 30 ml (ASTM D5890) is among the highest commercially available. Higher swell means better pore penetration, tighter seals, and lower application rates for your project.
Sourced from Northeastern Wyoming — home to the world's highest-quality sodium bentonite deposits. The mineralogy of Wyoming bentonite is unmatched by deposits found elsewhere.
Kiln drying exposes clay to excessive heat that can permanently damage crystal structure and reduce swell capacity. PondLock™ is sun-dried to preserve full performance.
PondLock™ exceeds the NRCS Conservation Practice Standard 520 requirement of ≥22 ml Free Swell Index by 36%. This means your project meets or exceeds federal soil conservation specifications.
Some bentonite products use chemical additives to boost short-term performance. These effects fade over time. PondLock™ achieves superior results through natural sodium content alone.
Backed by the Natural Waterscapes team — specialists in pond construction, leak diagnosis, and bentonite application. We help you calculate rates, select methods, and get it right.
Available in bags for small repairs and testing, or bulk sacks for full-scale construction and sealing projects. All products ship direct from Wyoming.
Ideal for small repairs, soil testing, and spot treatments. Ships via standard ground parcel.
View ProductApplication rate testing and small area treatment. Covers 9 sq ft at 6 lbs/sq ft. Ground parcel shipping.
View Product28 cubic feet per sack. Bottom drawstring discharge. LTL freight with liftgate available.
View Product42 cubic feet per sack. FTL flatbed or LTL van. Four lifting loops for on-site handling.
View ProductYour sodium bentonite clay worked awesome! I had a specific area sucking water and soil right through the dam. We dug a trench with an excavator and mixed in just two 45 lb bags. A few days later the overflow is overflowing again without any significant rainfall. I've tried other ways half a dozen times but never did it fill back in so well nor did it last.
The Granular Sodium Bentonite Clay has fixed my leaking pond! The leak was around the concrete drain — so bad there was a cavity about four feet deep and 30 feet long along the drainpipe. The pond filled up after several rains and has been at its normal level for two weeks. No discernible drop in the water level.
Whether you're sealing a backyard pond or lining a 50-acre lake, our team can help you calculate material requirements, select the right application method, and get PondLock™ delivered to your site.