What does insufficient storage in a small diameter drain lead to?

Insufficient storage in a small diameter drain primarily leads to an inability to support multiple outlets. When a drain is unable to accommodate the volume of water from multiple sources, such as fixtures or appliances, it can create a bottleneck. This restriction can cause water to accumulate at a faster rate than it can be drained, resulting in backed-up water or overflow situations.

This issue highlights the importance of properly sized drainage systems in plumbing to ensure effective wastewater management, especially in scenarios where simultaneous water usage occurs. Maintaining sufficient storage capacity is crucial for facilitating the proper flow of wastewater from all connected outlets, thus preventing drainage issues that can arise from overloading a small diameter drain.