The right sewerage system for an area with minimal rainfalls

The world of construction thrives on creativity, innovation and simplicity. The same group of words that has tailored technology to the phenomenon we have today; but believe it or not, piping and sewer systems are also forms of technological advancements in their own right.

sewage pipe

Having the current systems of piping is a result of the endless streams of trials and errors taken from past to create an organized pattern of discharge systems. Hence now, they can be applied efficiently to our homes, rural and urban communities as they assist in controlling the flow rate and quantity of rainfall, discharge and supply from or to households and communities.

However, in areas where the raining season is limited to a number of months, the COMBINED SEWERAGE is most ideal. Why? Having a system of one sewer line that is constantly working by transporting sewage discharge to be joined with a minimal quantity of surface run-offs from rainfall a few months a year is better than having a separate system with two sewer lines with only one working constantly (sewage) and the other (rainfall/ runoffs/ wastewater), for a few months of the year.

 Sewage systems exist to hold and transport used water/ run-offs from homes and communities to either to be disposed of or be treated and recycled.  But having a sewer with no content to transport is an issue that may lead other problems; this is why the separate system cannot be utilized in an area with little to no rainfall; the sewer channel for wastewater/ run-offs would be empty for parts of the year causing compilation of sediments and objects from the surface. Therefore, except you’re using a sewer of large diameter, constant cleaning and maintenance also has to be done to clear blocking objects which will imply added cost.



 The combined system has been practiced for decades in industries, as forms of sewerage and in various other methods but they can be a wrong choice if decision made with regards to surrounding factors tend to be poor so, here’s the real question for you as a house owner, or occupant… Can you combine wastewater pipes and sewage pipes in your domestic home?

Well, having a combined system as mentioned earlier is out rightly possible but its fit into a domestic environment is constantly questioned. With regards to its cost of material purchase and installation, the combined system helps you manage cost and minimalizes of the area taken by pipes. However, you run at a risk of certain scenarios

  • Strong foul odour escaping into every possible outlet in your home (even with vents);
  • Excessive or frequent emptying of septic tank if you use one;
  • Inability to maintain certain sections of the system separately (in other words; if the drain line is clogged or damaged at some parts, it affects the entire system; so fixing the entire system has to be dealt with)
  • Increased possibility of sewage backing up. (i.e. the discharge waste enters back into the piping system; the happens especially if clogs occur or septic tanks are filled up)

Therefore; to answer the question; YES, we recommend that you can have a combined system of drainage in your home if your combined sewage pipe is linked to an urban combined sewerage itself (i.e. the sewers that accept both sewage and wastewater too). IF NOT, OR YOU UTILIZE A PRIVATE SEPTIC TANK YOURSELF; GOING FOR A SEPARATE SYSTEM IS BEST. IT HAS A HIGHER INITIAL COST BUT YOU’D BREATHE EASY ONCE ALL THAT IS OUT OF THE WAY.



With going through the previous answer, it’s only normal for clients to ask, “Well, we realize that separate systems are best for our homes, but can we have them combined into one inspection chamber?”

Apparently, NO

A separate discharge system is basically the opposite of the combined system; a certain pipe line is designed and run to carry wastewater whilst another is designed to carry sewage separately following their unique courses to their final destination.

Hence, having them combined at any point eliminates the purpose of the separate system; compromises the whole operation and may further show a lack of professionalism from the technician/ plumber’s point of view. To break that into bits, here are some of the REASONS why it wouldn’t work.

  • Recurrent odour to home; let’s put this way, plumbers or any craftsman have different styles to which they approach their work, rules they follow depending on how much it works and how much they believe in them. It’s basically creativity and it’s a funny predicament however, there are codes and general laws guiding individual creativity or methods.

So in some regards; certain plumbers don’t install traps into separate discharge systems (especially the wastewater line) because they believe there’s no harm done since it’s just dirty water (but we recommend that you have traps fixed regardless). Hence, if at the long run you have both lines combining at any point whatsoever, the dwellers of that home will be left exposed to horrific smells from the sewage line because it has been linked back to the wastewater line.


  • Possible clogging; wastewater pipe systems are designed in such a way that majorly allows for water and very small sediments that happen to creep their way into the pipe.

Now the pipe, which is normally with the range of 2 inches to 3 inches of internal diameter can withstand small sediments but have them linked in inspection chambers may cause sewage to make its way into the opening of the wastewater pipe and create a block especially if septic tank is full. It further leads to wastewater not flowing well or backing up when ideally, both waters are meant to go their separate ways.


  • Poor maintenance culture; the purpose of an inspection chamber is maintain and repair piping systems should any issue allows to easily access. Having both lines combined into one would increase the difficulty of maintenance/ repair which might possibly lead to repair operation not properly done well.


  • Difficulty in re-separation; connecting both lines at any point complicates the plan of the whole system. The mixture of both dirty water and sewage waste into chamber may cause a mix up. Possibly allowing the entry to sewage into water pipe. This can be deflected only if the combined system is utilized from the beginning the end.




  • Mainly, one of the advantages for any form of combined sewer system is that it manages and conserves space utilized by piping system. In other words; although pipes used will be bigger in size, unlike having 2 smaller pipes, one fairly large one can be managed and fit into tight spots to reduce stress and complexity of installation.
  • They tend to be cheaper during the initial installation process; the separate system utilizes two pipes while the combined system utilizes one, economizing the cost.


  • Wastewater, dirty water or storm water which is typically recyclable is polluted by sewage waste causing them to be much less recyclable.
  • Although they do utilize one large pipe to take care of both wastes, they can be more difficult to install due to its size.
  • Damage to any section of the pipe would affect entire operations that involve the plumbing system.
  • There is a possible risk of frequent septic tank overflow if housing unit utilizes a septic tank primarily.
  • Nuisance of foul smells