A septic tank can become problematically full primarily because it's clogged with sludge.
Understanding why a septic tank reaches a problematic "full" state is key to preventing issues. While a septic tank always contains liquid and solids up to a certain level during normal operation, it becomes overfull in a way that causes problems when its components can no longer function correctly.
According to the provided information, a key reason for this problematic fullness is related to the solid waste management within the tank:
- The Problem: The tank becomes full because it's clogged with sludge.
- The Cause: This clogging happens when undissolved toilet paper or waste doesn't break down properly.
- The Process: Even though liquid/wastewater may still flow from the outflow pipe to the drainage area, the accumulation of undissolved solids creates the clog, leading to the tank becoming overfull.
- The Consequence: An overfull tank resulting from this clogging issue is a common cause of sewage backup.
In essence, it's not just the presence of liquid wastewater that causes a tank to be "full" in a problematic sense, but rather the buildup and failure of solids (sludge) to break down, leading to clogs and an overwhelmed system capacity.
