Step 1 – Determine Design

A Pond Free water feature recirculates with no open pond. A pump in a hidden basin sends water up to a waterfall weir or spillway, and the water cycles back down to the basin where the pump sits.

Waterfall / Spillway Wall: The weir or spillway is built into a wall or mounted on top, and water falls straight into the hidden basin. No streamway. Safe for kids and pets, easy to maintain, and works great in small yards.

Waterfall + Streamway: The waterfall flows down a streamway, or "river," to a dug-out basin where the water pools and the pump recirculates it. A longer stream means more water in transit and a longer liner.

Before you pick a kit: measure how much space you have, keep each waterfall drop at 3 ft or less, and plan on about 1,000 GPH of flow for every foot of spillway width.
Pond free waterfall example
✓ Waterfall or spillway wall
Waterfall / Spillway Wall
Water falls from a weir or spillway straight into a hidden basin. No stream, easy upkeep.
Shorter liner · Smaller basin
✓ Waterfall and streamway
Waterfall + Streamway
Water runs down a stream into a hidden basin. More movement and more visual impact.
Longer liner · More water in transit · Larger basin

Just one spillway on a wall? A Spillway Basin Kit is perfect for a single waterfall. Fountains and basalt bubblers are Pond Free features too. Call 1-866-831-6558 or contact us and we'll help you pick.

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Complete Step 1 first
Step 2 – Calculate Size
Stream and basin illustration

Water in Transit (WIT) is all the water moving down your waterfall and stream at one time. When the pump shuts off, it drains back to the basin. To keep the pump from running dry and cover water lost to evaporation, the basin has to hold 2 to 2.5 times your WIT.

WIT = Length × Width × 0.25 × 7.48
Length = every run and every drop added together · 0.25 ft = 3" average stream depth · 7.48 = gallons in 1 ft³
Water in Basin (WIB) = WIT × 2 (saves money) or WIT × 2.5 (safer)

Example: 1' + 2' + 6" + 1' + 6" = 5' long × 2' wide × 0.25 × 7.48 = 18.7 gal WIT, so the basin should hold 37 to 47 gallons.

Pond Free Size Calculator

Enter your waterfall and stream to get your Water in Transit, basin size, MatrixBlox count, and best-fit liner.

0.25 ft (3")

Add every run and every drop together, e.g. 1' + 2' + 6" + 1' + 6" = 5'. (6" = 0.5 ft)

Select your liner size below. Run the Water in Transit calculator first and your best fit will be highlighted in orange.

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Step 3 – Choose Liner
✓ LifeGuard EPDM
45-Mil EPDM Pond Liner
25-year warranty. Flexible, fish-safe, and the best choice for most pondless installs. Handles curves and rock shapes easily.
Not available for this liner size
✓ PolyGuard PVC
20-Mil PVC Pond Liner
5-year warranty. More affordable option. Flexible and fish-safe. Good if you're working with a tighter budget.
Not available for this liner size
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Step 4 – Consider MatrixBlox

MatrixBlox are hollow plastic crates that build your basin. They replace gravel, shrink the hole you have to dig, and give the basin structural support.

Full Block
31.5 gal
28" × 16.5" × 15.5"
Half Block
17 gal
28" × 15.5" × 9"
  • 96% void space vs about 30% for gravel
  • Less digging: a 3' × 3' × 1.5' basin holds ~96.9 gal with MatrixBlox vs ~30.3 gal with gravel
  • Holds weight: safe under boulders, pavers, and sod
  • Easy to install: panels snap together in seconds
How many blocks? Divide your Water in Basin (WIT × 2 or 2.5) by 31.5. Example: 109 gal ÷ 31.5 = ~3.5 blocks (3 full + 1 half).

Note: The 10,000 GPH kits always come with MatrixBlox, so they'll show up either way.

MatrixBlox
✓ Include MatrixBlox
Yes — Include MatrixBlox
Comes with MatrixBlox in the kit. More water storage, less digging. Recommended for most installs.
31.5 gal per full block · Less excavation needed
Not available at this size
✓ No MatrixBlox
No — Standard (no MatrixBlox)
You fill the basin with gravel instead. Gravel holds about a third as much water, so you'll dig a much bigger hole.
Lower kit price · ~3× bigger hole
Not available — MatrixBlox required at this size
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