DIY Small 20" Cascading Falls Kit [PB1854]

DIY Small 20" Cascading Falls Kit

Create a beautiful backyard waterfall without building a traditional pond. Our DIY Small 20" Cascading Falls Kit includes the essential equipment needed to build a natural-looking pond-less waterfall with a recirculating stream and concealed underground water reservoir.

Designed for smaller backyard landscapes, garden beds, and gently sloped areas, this complete pondless waterfall kit features a 20-inch cascading spillway and a hidden reservoir. Water flows over decorative stone, travels down the stream, and disappears beneath the gravel before being pumped back to the top.

The underground reservoir keeps the circulating water beneath decorative rocks and gravel. You get the natural appearance and sound of a flowing waterfall without the exposed water surface and ongoing care associated with a traditional fish pond.

Our waterfall kit combines the 20" Cascade Box, submersible pump, Canyon Matrix™, liner, and plumbing into one coordinated package. You won't need to select and match these primary components individually.

The DIY Small 20" Cascading Falls Kit is a good choice when you want a wider waterfall and a longer stream than our Mini 10" kit provides.

The current product summary recommends a stream approximately 7 feet long and 2–4 feet wide . Earlier technical charts and the installation manual describe an 8-foot maximum. We recommend planning conservatively and confirming your layout before installation.

The stream can incorporate changes in elevation, with the existing product description referencing designs up to approximately 2 feet in elevation change. Actual waterfall performance depends on the final height, plumbing, and rockwork.

The included Canyon Matrix™ measures 26.5" long × 16" wide × 13" high with its lid . Our installation manual recommends an underground reservoir excavation approximately 28" long × 22" wide × 13" deep .

Remember to allow space for the visible stream, decorative boulders, and surrounding landscaping in addition to the hidden reservoir.

Working with a smaller area? Consider our DIY Mini 10" Cascading Falls Kit . For other waterfall sizes and configurations, explore our complete pond-less waterfall kits .

We've included the primary equipment needed to build a recirculating pond-less waterfall. Decorative stone and site-preparation materials are supplied separately.

Pump Discharge Assembly

1.5" × 10' Black PVC Flex Pipe

Installation Kit

21-gallon nominal reservoir capacity

Removable pump-access lid

8' × 15' Rubber EPDM Liner

Protective Underliner

Installation components

Illustrated installation instructions

Muck Buster™ starter water treatment

Decorative rocks and gravel

Water for filling the reservoir

Excavation and site-preparation materials

Suitable electrical access

Landscape plants and decorative finishing materials, if desired

Important: Rocks and gravel are not included in the kit.

Component links are provided for product information and replacement-part reference. The listed primary components are included in the kit and do not need to be purchased separately.

Flow note: The included pump's 1,980 GPH specification represents its maximum rated flow. Actual flow at the waterfall depends on pumping height and plumbing resistance. The 2,500 GPH ratings apply to the Cascade Box and Canyon Matrix components, not the included pump.

Stream-length note: The current main product summary recommends approximately 7 feet, while the older technical chart and installation guide reference 8 feet. Confirm final sizing for projects requiring the full published maximum.

A pond-less waterfall recirculates water through an underground reservoir rather than an exposed pond.

The Canyon Matrix™ is installed inside the lined reservoir at the lower end of your waterfall. The included Mag-Drive pump sits inside the matrix and draws water from the concealed basin.

Water travels through the PVC flex hose to the 20" Cascade Box positioned at the top of the stream. The Cascade Box helps distribute the water before it flows over the spillway and down your arranged rockwork.

As the water reaches the bottom, it passes through decorative gravel and returns to the hidden reservoir, where the cycle begins again.

The result is a continuously flowing backyard waterfall without a traditional open pond.

The DIY Small Cascading Falls Kit includes the main equipment, but installation still requires excavation, liner placement, plumbing connections, and stone arrangement.

Select a location where the waterfall can be enjoyed from your home, patio, or outdoor living area. Plan the stream route, waterfall elevation, and underground reservoir location before digging.

Our installation manual recommends an excavation approximately 28" long × 22" wide × 13" deep. Remove sharp roots and stones, then install the protective underliner and rubber liner.

Position the Canyon Matrix inside the lined basin. Leave approximately 3" of space along each slotted side so water can pass through rinsed river rock into the reservoir.

Shape the waterfall drops and place the 20" Cascade Box on a firm, level base at the top of the stream. Route the flexible pipe from the reservoir to the Cascade Box and connect the included plumbing components.

Use larger stones to form waterfall drops and smaller gravel to finish the streambed and conceal the reservoir. Keep the liner edges high enough to contain the water as it travels downhill.

Fill the reservoir before starting the pump. Check for water escaping the stream edges, confirm the spillway is level, and make final adjustments to the stone placement and waterfall flow.

Installation tip: Keep approximately 6" of excess liner around the basin and stream edges during installation. Do not permanently trim the liner until the waterfall has been tested.

Always locate underground utilities before excavation. Follow the installation manual and use a properly grounded, GFCI-protected electrical connection.

Pond-less waterfalls are generally lower-maintenance than traditional open ponds, but the pump and reservoir still need attention.

Check the reservoir water level regularly. Water lost through evaporation and splashing must be replaced so the pump remains submerged and never runs dry.

Remove fallen leaves and debris from the stream, inspect the pump intake, and clean the Cascade Box filter media as recommended.

The Canyon Matrix includes a connection for an optional automatic water-fill system. A compatible auto-fill kit can help maintain water levels but is sold separately.

In freezing climates, winter operation requires monitoring for ice dams that could redirect water outside the stream. If shutting the system down, clean and store the pump according to our seasonal guide.

View Our Pond-less Waterfall Maintenance Guide

We offer several complete waterfall kits with different spillway widths, pump sizes, stream lengths, and reservoir configurations.

Use the comparison chart below to find the best option for your landscape.

Stream sizes are planning guidelines. Final dimensions depend on the landscape, elevation, plumbing, and liner layout. Some older comparison charts differ from current product-page or installation-manual specifications.

Shop All Pond-less Waterfall Kits

Regular maintenance helps keep your pondless waterfall flowing properly throughout the season.

Check water levels regularly and refill as needed.

Remove leaves, twigs, and other debris from the stream.

Inspect the pump, tubing, and plumbing connections.

Clean the pump intake and pre-filter when necessary.

Inspect and clean the Cascade Box filter media.

Use water treatments according to their instructions.

During freezing weather, ice can redirect water outside the stream and cause the reservoir level to drop. Monitor operating waterfalls carefully during winter conditions.

If you shut the waterfall down, clean the pump and remove it for storage in a location where it will not freeze. Our maintenance guide recommends keeping the underground reservoir at least half full during winter shutdown rather than draining it completely.

Follow the official maintenance guide for complete winterization and spring startup instructions.

Use our official installation guides and technical resources when planning and maintaining your waterfall.

Watch our Blue Thumb DIY Cascading Falls installation walkthrough to see how the underground reservoir, liner, pump, and waterfall components work together.

Blue Thumb official installation video. General DIY Cascading Falls installation guidance; follow the PB1854 installation manual for exact kit specifications.

Different components in this complete waterfall kit have separate warranty coverage.

20" DIY Cascade Box: Lifetime manufacturer's warranty against qualifying manufacturing defects.

Canyon Matrix™: Lifetime manufacturer's warranty against qualifying manufacturing defects.

Large Mag-Drive Pump: 5-year limited warranty. The impeller is excluded.

Warranty coverage is subject to the manufacturer's published terms, proper installation, and applicable exclusions. The entire kit should not be represented as having a lifetime warranty.

Read Our Complete Warranty Information

Not sure whether the 20" Cascading Falls Kit is the right size for your backyard? Our Sales and Technical Team can help you compare waterfall sizes, understand reservoir requirements, and plan your installation before ordering.

A pond-less waterfall is a recirculating water feature that stores water in an underground reservoir instead of an open pond. Water flows down a constructed stream and disappears into gravel before returning to the hidden reservoir.

The current product summary recommends a stream approximately 7 feet long and 2–4 feet wide. Older technical charts and the installation manual describe an 8-foot maximum. We recommend planning conservatively and contacting our Sales/Tech Team when designing near the maximum length.

The kit includes the waterfall box, pump, Canyon Matrix reservoir, plumbing, rubber liner, protective underliner, installation materials, and listed startup treatment. Decorative rocks and gravel are not included. You will also need water, suitable electrical access, and site-preparation materials.

The Mini kit uses a 10" spillway and a 1,495 GPH pump for a planned stream up to approximately 4 feet long. The Small 20" kit provides a wider spillway, a 1,980 GPH pump, and an 8' × 15' liner for a longer, wider stream.

Yes. The kit is designed for DIY installation, but it requires excavation, liner placement, plumbing, and stone arrangement. Follow the official installation manual and consider professional help if you are unfamiliar with this type of landscape construction.

Yes. The Canyon Matrix includes a connection for a compatible automatic water-fill system. This accessory is sold separately and can help replenish water lost through evaporation and splashing.

No. The included Mag-Drive pump has a maximum rated flow of 1,980 GPH. Actual water delivery decreases with additional pumping height and plumbing resistance. The pump's maximum head specification is 20 feet, but that does not mean it delivers its maximum flow at that height.

Winter operation requires careful monitoring. Ice can divert water outside the stream and lower reservoir levels, potentially damaging the pump. If you shut the system down, remove and store the pump where it cannot freeze and follow our maintenance guide.