How to Install a Pond Liner

Installing a pond liner can be a straightforward task that can be done efficiently if a few important steps are followed. First consider the two types of high-quality liners: For a large agricultural or recreational pond a reinforced polyethylene liner will offer flexibility, puncture resistance, tear strength and will last 20-25 years when covered or 10-15 years exposed to the sun. For smaller landscape ponds EPDM Rubber liners are ideal for ornamental water gardens including waterfalls and streams. EPDM liners are UV stabilized for 20-25 years when exposed to the sun and natural looking. Secondly the excavation of the pond and the type of soil where the pond is to be built are critical steps to be planned carefully to guarantee success.

Excavation

When excavating a large pond, you want to end up with an area on the inside perimeter that has a very gradual slope so that if a person or animal needs to get out, it won’t be a struggle. Constructing a strong, tall fence around the pond will prevent animals and people from endangering themselves. Always plan on having a spillway, a low spot for the water to go down and away from the pond. Digging a shelf around the perimeter of the pond that is at least 2 feet wide that will end up underwater by about 1 foot will allow easy entry way and exit for those who want to use the pond for recreation and to keep animals (who manage to get into the fenced area) safe. When the liner is installed, and before the edges are secured, place some rocks on this shelf to help define it. Leave some slack in the liner near the top edge to allow for this shelf to be pronounced (i.e., visible), so it will be a safe place to stand. Smaller ponds are often hand-dug. It’s a good idea to have the deep end of the small pond at least 3 feet deep with a few large rocks in this deeper area for smaller fish to hide from larger fish or animals like raccoons or birds. A pump can be placed in this area to recirculate the water in the pond. The pump and adding some beneficial aerobic bacteria will keep your pond healthy for the fish and attractive.

Choosing the Best Liner

For the highest quality water containment with the longest lasting material, reinforced polyethylene liners are the best choice. Made to order at the factory, they usually ship within days, allowing speedy installation. These poly liners commonly come in four thicknesses: 20 mils, 24mil, 30 mils, and 40 mils. If you are installing over sandy soil, then the 20 mils should be thick enough. They offer flexibility, tear resistance, and strength that you would expect. The 40 mils liner has the highest puncture resistance, is a much stiffer product, and harder to install. Their 15-year life expectancy exposed to the sun makes them the best choice for very intense sun baked parts of the United States.

Installation

A typical installation goes something like this: 1. The liner comes folded and rolled on a cardboard core and will be rolled out along the length of the pond. Initially to put the liner in place heavy equipment like a backhoe is used to lift and move the liner. 2. A team of workers (one person every 10-15 feet) line up along the leading edge of the liner and proceed to pull the liner down to the bottom of the pond and up the other side. If the liner is too heavy to pull it up the side of the pond, a four-wheel-drive truck with a winch can be attached to the middle of the leading edge (sandwich the liner with 2×6 lumber that will be bolted to the liner) with ropes or chains. The team of workers will continue to pull the liner along with the aid of the 4×4 truck until the liner is up on the bank, where it can be tucked into the trench. Secure the liner in the trench with a little bit of dirt. Don’t fill the trench until the pond is full.

Underlayment

Non-woven protective geotextile material is available and may be needed to lay down first before you install the liner if there are sharp rocks or roots exposed. This product is a long-lasting, puncture-resistant, and cost-effective solution for protecting thinner polyethylene liners or the softer EPDM liner material.

Long-lasting pond liners are important to farmers, vineyards, and property owners large and small. Our water is a very precious resource and collecting it in the winter when the rain and snow are plentiful will give you irrigation water for the dry months of summer.