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4 Major Characteristics of a Gravity Sewer

plumber stives 4 Major Characteristics of a Gravity SewerA Gravity Sewer System is the most conventional and commonly used sewage system and wastewater collection method. Most communities opt for this type of sewage since it is low maintenance; its operational cost is relatively inexpensive since it does not need pumping stations and other means of moving the wastes from the residential space and into treatment plants.

This type of sewer has a certain declivity degree to make sure that the liquid wastes can freely flow without the aid of a pump. The self-cleansing factor also has a hand in keeping the maintenance cost of the system low. Another characteristic that the Gravity Sewer should have is that the lines should be as straight and direct as possible. The contractor should avoid having to make curves and bends as much as possible. All these properties are very useful in making the system effective in its function. Here are other characteristics that a Gravity Sewer should possess to make it useful and a staple sewer variation in every community:

1.Slope Declivity

As mentioned before, there should be a specific declivity degree to any Gravity Sewer. The system should always be going downhill to make sure that the flow is secured and that the self-cleaning flow of the system is maintained. There should be a slope directed downwards from the community to the treatment plant. Particle accumulation can be avoided with a certain velocity maintained throughout the sewer pipe with its self-cleaning properties to keep the maintenance and the flow capacity active.

2.Design Flow

When opting for a Gravity Sewer System, the flow velocity and capacity of the sewer system should be organized and calculated beforehand in order to meet the needs of the wastewater flowing inside the pipes. The flow should be able to cope with sudden rise and fall of the water volume and density in case the population increases. A Peaking Factor should be computed as an allowance for cases when unexpected events happen that can alter the load density and volume such as strong rains that come often to fill up the pipe line and population increase which directly equates to a liquid waste increase.


The Gravity sewer is directly dependent on the gravitational pull and slope of the positioning of the pipes to transport its load from the source to the treatment pipe or whatever type of sewage treatment method the community uses. The same reason why the pipes should be laid at a specific degree of declivity to support the flow capacity of the system without having to require a water pump or other means to pushing the water that would make the community spend more on its wastes than what is needed.

4.Pipe Circumference

Many professionals suggest that sewer pipe diameter is a very huge factor in dealing with the flow capacity. It can make the flow effective or constricted. Remember that when choosing the size of the pipe for an industrial sewer system, bigger pipes allow freer flow while smaller pipes restrict flow and may lead to accumulation and blockage if it continues.