For liner-based ponds, prioritize EPDM rubber liners (at least 45 mil thickness) due to their flexibility and UV resistance. If sourcing prefabricated fiberglass ponds, ensure they have a reinforced gel coat to prevent osmotic blistering. Structural components must withstand hydrostatic pressure; therefore, check that the supplier provides reinforced sidewall designs. For concrete builds, ensure the use of non-toxic, fish-safe crystalline waterproofing admixtures or specialized pond epoxy coatings.