Say goodbye to sourcing pond liner and underlayment from two different suppliers - this 15 x 20 ft. combo pack ships a 45 mil EPDM rubber liner alongside a matching nonwoven fabric underlayment, covering both layers of the backyard pond build in one shipment. The 45 mil / 1.1 mm EPDM with 25 kN/m tear strength and 9 MPa tensile strength resists the puncture and tear stress that destroys thinner pond films after one season, and stays flexible through full sun, freeze-thaw cycles, and the freeze-up that splits cheaper PVC liners across a Midwest or New England winter. Underneath, the nonwoven fabric underlayment creates a smooth, abrasion-buffering surface between the EPDM and the pond floor, slowing the punctures that settled rocks and tree-root tips drive into unprotected liners - the small upgrade that extends EPDM service life by years. Install runs as a clean weekend project: dig the pond outline, clear debris, lay the underlayment across the cavity, drop the EPDM liner over it, trim both layers to fit, and weight the perimeter with stones or bricks. The 15 x 20 ft. / 4.57 x 6.1 m footprint covers a moderate koi pond, a small reflecting pool, or a backyard water garden for plants, fish, ducks, and turtles, while supporting the kind of low-maintenance ecosystem that turns weekend gardening into a Saturday-morning coffee tradition. Trim leftover material into a weed barrier or planter liner to extract full value from the kit.