Plug the numbers you obtain into the following standard formulas to determine the correct liner and/or underlayment size that you will need:

L + 2(D) + 2 = Liner Length

W +2(D) + 2 = Liner Width

Example A: Maximum measurements are 8' long x 10' wide x 2' deep

Length: 8' + 4' + 2' = 14'

Width: 10' + 4' + 2' = 16'

Liner and Underlayment size is 14' x 16'

As we sell liner in 5' increments, you would need to purchase a piece measuring 15' x 16' or 14' x 20' (your choice).

Example B: Maximum measurements are 14' long x 19' wide x 3' deep

Length: 14' + 6' + 2' = 22'

Width: 19' + 6' + 2' = 27'

Liner and Underlayment size is 22' x 27'

As we sell liner in 5' increments, you would need to purchase a piece measuring 25' x 27' or 22' x 30' (your choice).

Note: Allowing for extra liner will avoid shortages that are caused by miscalculations, changes in plans, or other unforeseen circumstances. Remember to also allow enough liner for the waterfall and/or stream.

While there are many varieties of liners for sale on the market, we sell Firestone 45mil EPDM rubber liner that is both fish and plant safe. This product is a true standard in the pond building industry. Please realize that using swimming pool liners and rubber roofing products can cause serious problems in your water garden as these products are not fish and plant safe.