The size of a wastewater system is directly related to the size of the community it services. Residential, commercial, and industrial population density, as well as physical drainage basin size all factor into a successful wastewater system design.
As the design engineer, we must analyze the conveyance limitations of an existing wastewater main to determine the impact of constructing new wastewater laterals. If a wastewater main is shown to have exceeded capacity or exhibits surcharging then improvements to the existing system will have to be designed and constructed prior to adding service laterals.
In Texas, wastewater system design involves the use of gravity as the force behind the sewage as it travels through buried pipes to the treatment facility. When existing landscape and/or proposed improvements will not allow for a gravity system to be installed, lift stations and force mains are sometimes an acceptable solution.