What makes a vinyl in ground pool keep filling up on own?

High water table: One common reason for a pool filling up on its own is a high water table. If the water table in the area is high, it can seep into the ground around the pool and raise the water level. This is more common in areas with naturally high water tables or during periods of heavy rainfall.

Cracked pool shell: Cracks in the pool shell can also allow water to seep in. This can happen due various reasons, including extreme temperature fluctuations, ground movement, or improper construction. If the cracks are significant, water will seep through and cause the pool to fill up.

Damaged or loose plumbing: Damaged or loose plumbing connections can also lead to a pool filling up on its own. If there are any leaks in the plumbing system, such as a broken pipe or a loose fitting, water will continuously flow into the pool.

Poor drainage: Inadequate or blocked drainage around the pool can also cause water to accumulate and eventually overflow. If the pool's drainage system is not functioning correctly, water will not drain away properly and can cause the pool to fill up.

Backwash line: If the backwash line from your pool's filter system is not properly connected, water may flow back into the pool. This can happen if the line is broken, disconnected, or not sealed properly.

To determine the exact reason why your vinyl in-ground pool is filling up on its own, it is a good idea to consult with a pool professional or a qualified contractor who can assess the issue and provide an accurate diagnosis.