How to Build a Pond with a Flexible Liner

Flexible liners offer versatility when creating and designing a pond. Use of a flexible liner allows you to make a pond any shape or size you want. Flexible liners can be purchased in 10 feet, 15 feet, and 20 feet widths.

Materials Required:

  • Rocks, patio or paving stones, or other material to edge the pond
  • Hose, rope, string, or stakes
  • Flat blade shovel
  • Plank and level
  • Measuring tape
  • EPDM liner
  • Geotextile fabric
  • Mortar or foam adhesive
  • Wheel barrel
  • Shovel
  • Spade


  1. Determine the size and shape of the pond. Mark the area using a hose, rope, string, or stakes to outline the shape of the bed. Do not build the pond in close proximity to trees/shrubs whose roots may puncture the pond’s liner.
  2. Dig the pond to the desired depth. Create shelves at different levels to permit the growth of a variety of plants. Angle the sides of the pond’s deep area.
  3. Remove sharp stones and tamp the entire area, including shelves.
  4. Using a flat bladed shovel, create a flat lip along the pond’s edge to accommodate edging materials. 
  5. Use a plank and level to ensure that the hole and shelves are level. 
  6. Measure the pond’s depth, length, and width. 
  7. Purchase enough liner to cover the bottom of the pond and overlap the edges once the edging material is in place. The liner will stretch once under the pressure of the water. To determine the required amount of liner, use the following formulas:

Length (ft) + [2 X Depth (ft)] + 2 ft of overlap = Required length

Width (ft) + [2 X Depth (ft)] + 2 ft of overlap = Required width          

  1. Lay geotextile fabric in the pond to protect the liner.
  2. Allow the liner to warm for a few minutes on pavement, making it more flexible and easier to position. 
  3. Place the liner loosely in the excavated area with even overlap on all edges of the hole. Weigh the sides down with some rocks.
  4. Beginning filling the pond with water to settle the liner into place. As the pond fills with water, adjust the liner so it moulds to the sides of the pond and smooth out as many wrinkles/creases as possible. Adjust the rocks to keep the liner from overstretching.
  5. Lay the edging material around the perimeter of the pond to create an aesthetic edge and to hold the liner in place, ensuring the liner extends under the edging material. Mortar or foam adhesive is useful to keep the edging materials in place. Trim excess liner. 
  6. Fill the pond completely with water.