Types of Pond Liner

• All ponds have different types of liner. It's important to know what kind you have before doing any troubleshooting. The two main types of liner are flexible and non-flexible. Non-flexible liners include clay, concrete or fiberglass. Most non-flexible liners are a permanent part of the pool and can't just be taken out without some heavy labor.
  
  Flexible liner includes EPDM liner, PVC liner or geotextiles. Each of these liners have their own special properties, but they all look much like a pool cover. They are placed inside the pond and hold the water. These liners are easier to use and less expensive, but they are also more prone to leaks than a non-flexible liner.
  
  

Leaks

• Several factors can cause a tear in the pond liner, including jagged rocks or household pets playing near the pond. If the ponds water level seems to be going down, don't jump to the immediate conclusion that it is a leak.
  
  First, inspect the water pump and the pipes. If the connections are not tight, water can just be leaking from pipes. If your pond and waterfall has a streambed, check that nothing is obstructing the water flow. Discard any debris on the streambed and wait to see if the water levels return to normal.
  
  If these don't work, start inspecting the liner. One way to do this is to slow down the flow of water through the pump. If the water level still recedes overnight, you may have a rip in the liner. Another option is adding a colored dye to the pond. If the dye starts moving toward one direction before disappearing, this can help you pinpoint where a leak may have formed.
  
  The last resort is waiting to see when the water levels stop receding. If it stops, the water may have already passed the rip or hole in the liner.
  
  

Repairing Liner

• For flexible liner, several types of glue and adhesives can fix leaks. An EPDM repair tape can be used on EPDM liners. The tape is attached over the rip and smoothed out to eliminate any air bubbles. To make certain the leak will be stopped, place EPDM tape over the top and bottom portions of the tape you already fixed into place.
  
  For more rigid liners, such as fiberglass, use a piece of PVC sheeting. A PVC primer is put over the leak and then the patch is glued into place. Follow all of the manufacturer directions if you buy a PVC or EPDM repair kit.
  
  Finally, repair non-flexible liners, such as concrete, by just caulking the area. Find the leak and drain the pond to that level. Then apply a concrete patching material inside the hole with a caulking gun. Smooth out the bonding agent and let it dry before refilling the pond.