Building a Backyard Waterfall: Mound, Liner & Rock Stacking Basics

A backyard waterfall needs elevation — either a natural slope or a built mound. Flat yard? Build a berm. The concept is simple: water flows down; you stack rocks to guide it.

Core Components

1. Reservoir (lower pond): Liner or preformed shell, holds water + pump.
2. Pump: Submersible, rated for head height + flow (e.g., 1,000 GPH @ 4 ft head).
3. Plumbing: Flexible tubing from pump to top of falls.
4. Waterfall box/spillway: Distributes water evenly across rock face.
5. Liner under falls: EPDM liner draped over mound, tucked into pond — catches all splash.
6. Rocks: Flat "spill rocks" for sheets; chunky "frame rocks" for edges.

Building Steps

1. Shape mound: Soil, compacted, sloped 2:1 (run:rise).
2. Lay liner: Generous overlap into pond — no seams in splash zone.
3. Place spillway box at top, level, backfilled.
4. Stack rocks: Start bottom, work up. Spill rocks tilt slightly forward. Foam gaps with waterfall foam.
5. Test flow: Adjust rocks until water sheets, doesn't trickle or splash out.
6. Plant edges: Marginals soften rock, hide liner.

Pro Tips

• Use "waterfall foam" (black expanding) — locks rocks, directs flow.
• Overlap liner like shingles — every piece over the one below.
• Pump in skimmer box or pump vault — easy access, pre-filtered.
• Lighting: Submersible LEDs at spill points = night magic.

Start small. A 3-ft falls on a 4-ft mound is a weekend project. The sound of water is the reward.