Calculating Storage Allowance


The sump can be used for everyday operations with the storage only being used in an emergency situation.


The tank should be installed with a 2° angle so that gravity moves the liquid to the right-hand side to help it move to the sump side of the tank.

Storage selection

Selecting the correct storage allowance in wastewater pumping is a crucial design element. You run the risk of a catastrophe or an oversized unit if you get this wrong. Getting this right, you have a well-running pumping station designed correctly.

The British Water loading units need to be considered when a PPS is next to a building due to the increased chance of flooding. The inlet pipe must be above the emergency storage area (as shown) to avoid this.


In this example, the inlet pipe is lower than the top of the emergency storage area. This means there will be a backlog of wastewater if the emergency storage is at maximum capacity.