A long-lasting water feature starts with the right liner and underlayment. Our Water Feature Underlayment collection carries fish-safe EPDM pond liners in a variety of sizes and formats, geotextile underlayment, rock pads, seam tape, repair kits, and other essential materials to protect and seal your pond or waterfall from the ground up. Whether you are building a new water feature or repairing an existing one, these products provide the durable, watertight foundation your build depends on.