Cracks in a septic tank can be an easy fix or they may be a sign that the tank and possibly the rest of the septic system are in disarray, requiring attention.
Most septic tank systems installed prior to 1980 were constructed of cement with any lateral or field lines made from PVC, cast iron or clay tile. As the cement tanks age, micro-cracks develop throughout the entire system. The small cracks are generally normal and do not pose a major problem provided they do not enlarge to a point where raw sewage is allowed to escape. Many tanks with small cracks experience no detrimental effects what so ever and are completely functional.
Cracks can occur in many ways. Areas that experience earthquakes, such as California, are more prone to cracking than other areas. Septic tanks in these areas should be inspected more frequently than in other parts of the country. Heavy machinery, automobiles and in some cases lawn tractors can all contribute to cracks in the system. Swimming pools and yard fixtures such as sheds or heavy landscaping decorations or improvements can also contribute to cracking and system weakening.
While small cracks may not be an issue with seepage or leakage, they may allow ground water to pass from the surrounding soils into the tank itself, causing elevated liquid levels inside the tank. This high liquid level can cause excess pressures within the entire system which can result in gurgling sounds, odors, wet spots, slow flushing, slow drains or internal system damage within the septic system or your building.
Cracks in the septic tank lid can be a major problem and should normally be addressed immediately since they pose a health danger. Cracked lids can weaken to a point where any moderate weight will cause a collapse. Small children and pets may suddenly drop into the tank should the tank lid become unstable.
While minute septic tank cracks may be acceptable, having a professional inspect the entire system will help determine whether or not these hairline cracks are a risk that needs to be taken care of. Septic tank systems are designed to last many decades with proper maintenance and routine inspection is a great way to ensure the stability, functionality and safety of your system.