Leak Detection

• The first place to check when it comes to a leak in a swimming pool is within its basin. Also, pool fittings and skimmer faceplates can develop leaks. A leak in a pool's basin is detected through use of simple dye test to track colored water making its way to the leak. If you suspect you have a leak coming from your pool's filter fittings or the skimmer perform a visual inspection for moisture or drips around such equipment.
  
  

Dye Test

• Find underwater leaks in any type of in-ground swimming pool basin by using special dyes and syringes sold in pool supply stores. You can also make up a swimming pool leak detection kit by using dark food coloring and a turkey baster. Get as close to the site of a suspected pool basin leak as possible and then squirt dye, watching to see where it goes. If a pool basin has a leak, dye introduced near it will quickly exit through that leak.
  
  

Hydrostatic Valve

• An in-ground concrete or fiberglass swimming pool is typically fitted with a hydrostatic valve. Check under the pool's main drain cover for the hydrostatic valve and apply dye near the main drain to see where it goes. A hydrostatic valve helps equalize pressure between the water in a pool basin and the groundwater beneath it. Old, worn out hydrostatic valves are often the culprits when it comes to an in-ground swimming pool leak. Have your pool's hydrostatic valve replaced about every five years.
  
  

Considerations

• In-ground swimming pools have underground plumbing systems that are inaccessible to visual inspection or use of dyes to detect leaks. Consult a swimming pool leak professional if you suspect leaks in its underground plumbing. Also, if air bubbles are coming from your pool's water return ports there's a leak in your pool's return lines at some location along those lines. Lastly, other areas in a swimming pool that tend to leak are sharp corners or along any seams.