Why two original materials failing together explains most Montgomeryville pool leaks
Most pool water loss conversations start with the homeowner describing what they noticed first, the water level dropping faster than usual, the auto fill valve running more often than it used to, or a water bill that is higher than anything the previous summer produced. These observations are accurate and important, but they describe the effect rather than the cause. Understanding the cause in Montgomeryville requires looking at what was installed in the late 1980s and early 1990s and what those materials were realistically designed to last.
Original PVC skimmer body sealant has a typical realistic service life of 15 to 20 years under normal pool conditions. A pool installed in 1990 is now carrying sealant that is approximately 15 to 20 years past that design expectation. The freeze and thaw cycling that every Montgomeryville winter produces at the waterline adds additional stress to exactly the joint where the sealant does its work, because ice forms at the waterline and exerts expansion pressure outward against the skimmer body and the surrounding pool shell. Over 35 winters of this specific stress pattern, the original sealant at a Montgomeryville pool from this era has absorbed far more loading than it was designed to handle.
Original underground PVC solvent cement joints have a typical design life of 25 to 30 years. A Montgomeryville pool from 1993 that still has its original underground plumbing is now running on joints that are 5 to 8 years past their design expectation, with the direction change fittings within each circuit having absorbed the most cumulative thermal stress of any point in the system. When both of these materials fail within the same season or the same year on the same pool, it is not a series of unfortunate coincidences. It is two independent materials reaching the end of their realistic service lives at approximately the same time in a pool built during the same specific construction era.