When census data are not available to determine a growth rate or model, or even when the average final population that will be served by an undertaking is known, one can only arbitrate the known value for the initial and final population. For example, in a subdivision with 200 social lots, we could arbitrate that each lot has a family of 4 or 5 people. Assuming that at the beginning, between 10 and 20% of the subdivision is occupied. With that, we would have to evaluate in the sewer network if the minimum tensile tension is met, in order to avoid allow sediment to accumulate in the pipeline. At the end of the project period, the entire subdivision is occupied and we have to assess the network's flow capacity.