Uneven Ground

• Above-ground and in-ground swimming pools need to be installed properly, above all else. If the ground beneath an above-ground pool isn't level, too much stress will be put on uneven pool wall sections, causing them to eventually collapse. The holes for in-ground swimming pools also have to be excavated properly, especially for pool floors. The immense water weight in a 15,000-gallon pool (124,000 pounds) will press on an uneven pool surface greatly, which could lead to collapse.
  
  

Pool Draining

• Depending on what they're made of, certain types of in-ground swimming pools could collapse if they're completely drained. For one, if a fiberglass-lined in-ground pool is fully drained, groundwater beneath the swimming pool could lift its liner shell upward. A completely drained in-ground pool with poor groundwater drainage is under a great deal of stress. Unless an in-ground pool is in dire need of complete repair or renovation, it's not a good idea to drain one completely.
  
  

Structural Changes

• Making structural changes to a swimming pool can cause it to collapse. Both above-ground and in-ground swimming pools are supported by the structures erected to hold the water in. If you remove a piece of a swimming pool's structure, the pool's water weight will press any against weakened areas. Examples of pool structural changes include removing buttresses on above-ground pools and excavating next to an in-ground pool's basin. Always consult a swimming pool professional before modifying your swimming pool in any way.
  
  

Considerations

• You should always have a pool professional perform a complete pool draining if one needs to be done. When it comes to above-ground, steel-framed swimming pools, you should regularly inspect them for signs of corrosion. Any weakening of a pool's skeletal strength or a deficiency in its integrity will eventually cause big problems that include possible collapse. Last, make sure to properly winterize your swimming pool to prevent ice formation from cold temperatures that could overly stress your pool.