An epdm pond liner is preferred by pond builders and serious hobbyists.
A rubber pond liner can take extremes in temperatures, abuse and will still perform very well.
Epdm stands for ethylene propylene diene monomer which is the chemical mix for this type of rubber.
Rubber roofing material commonly used on commercial buildings is also epdm but contains fire retardants and algaecides. These are the chemicals that will harm your fish and plant life, so look for a product stamped by the manufacturer as: fish and plant safe.
With rubber pond liners there is little or no up keep needed. The type of rubber used has a lot of give or stretch built in,so if your dog or deer get into your pond they won’t tear it up with their toenails or hooves.
It will also conform or stretch around any stone or root that may be under the liner. When stone is placed on top of the liner it will give or stretch under the weight. It also has a very good UV protection built in to give a very long life span, which makes a rubber liner very maintenance free.
With two thicknesses of 45 ml and 60 ml to choose from the 45 ml is preferred by most all pond builders. It is very flexible even when cold and conforms easily to a well designed pond.
So if you are looking for a long life span and easy or no maintenance then an epdm pond liner is the way to go.