One solid way of stopping foul smells from floor drainages

Getting strong foul smells from sewage drains or from floor drains is a common problem in houses with elements of plumbing; the common causes and treatments are mostly easy to detect and solve; but how about stopping them permanently, think about it. Because let’s face it, the issues you have now can be fixed, but it might come back if you’re not cautious enough to employ preventive measures on a constant basis. That’s pretty disgruntling to us, because honestly we just can’t put our clients in a state where they have to constantly mix chemicals together, checking this and that. I mean it’s all part of maintenance and that has to be done, but not too frequently as these issues can sometimes demand optimum closure and mostly you’d have to pay for that.

Hence, in this article; we’d be sharing with you a direct method of stopping foul smells for good but it is quite uneasy to achieve except if you are either constructing, renovating your home or you’re at least willing to. If the method doesn’t work for you, every other possible cause of the foul smells will be diagnosed and a simple solution will be given for each one after this method. If that is what you require, kindly skip this method to get into that; if not….


We’re more of old school kinda plumbers, we try our best to innovate, to be modern but still keep some of old formulas because we believe it’s a healthy mix. So let’s put this into perspective, to stop drains from releasing fouls smells permanently,” is to separate the water waste from the sewage waste” because the current trend now is to have both discharge lines combined. In simpler terms; the pipes draining sewage/solid waste should be run separately from the pipes draining water waste as currently, most of the pipes we have in our houses work for both.

We discovered that the idea of the plumbing systems these days is to reduce the cost spent, by combining both units (sewage and water discharge) and to provide traps that prevent entry of foul odors coming from the sewage back into the water drains.

The innovation is great but it works the best in industrial environments because an industry will simply spend a lot on plumbing and piping systems, to construct and to maintain; so it makes sense if they accept innovations to reduce costs and get near similar results. Reduction of cost to them is huge, we’re talking possible millions in currency and they hire people to maintain the plumbings anyway.

However in the domestic space; it’s ideal enough to stay with the old school method, the modern system will reduce cost of construction minimally and would require constant maintenance which at the long run might cost more than when you just have separate drainage systems for both.

It’s a pretty direct solution but homes with combined discharge units that are already constructed will require that you take out the whole discharge lines and re-structure them, it’s possible this can be done if your plumbing arrangements allow for it, ; which will involve the breaking of concrete in various parts of house if the pipes are concealed.

combined system of drainage

To find out if your plumbing structure allows for it, I suggest you try to get the plumbing plan of the house and contact your plumber to analyze the possibility and risk of getting of having this achieved and ofcourse its cost. This method is best used when constructing your home from scratch; let’s get into its facts and steps to analyze it better;


  • Separate plumbing lines allows for reduction in quality in pipes, when you are trying to drain large masses of combined waste, your pipes are required to be large enough to convey conveniently and be resilient to the weight of the waste, however if waste are conveyed separately, with smart inductions, the size and strength of pipes needed will be a lot less.
  • Water traps will not be necessary for your floor drains” when you separate the discharge lines, the major benefit of the separate drainage system is that it channels the foul and water wastes separately. The foul waste carries the odour; but its lines can be completely shut to be open only at the septic tank outlet, so no foul odor can be brought back into the house except through the installed vents into the outer atmosphere.
  • Separate piping systems are expected to have major clean out points assigned at various positions; majorly at points that access the major pipe for discharge and sewage.


  • Highlight appliances for sewage waste and water waste; toilets, urinals, squat pads and any appliance used for biological waste should be highlighted and marked to be connected to one line of discharge pipe. Floor drains, wash hand basins, kitchen sinks and other appliances that discharge mere dirty water should be combined to form another discharge pipe.
  • During construction, ensure both cleanouts exists for both lines, and no, not the clean outs in the floor drains, but cleanouts along the main pipe of each discharge system.
  • Separate chambers should be provided for each line too; the main point here is to ensure that both discharge line do not meet at any point all through
  • Provide a septic tank for the sewage pipes, a soak-away for the waste water pipe and keep them fairly apart to prevent contact; if your budget for a soak-away doesn’t cut it, you can channel the wastewater pipe to a nearby gutter /closed channel if it is allowed in your community.

It’s understood that your community rules and guidelines for plumbing might not allow for separate channeling of both wastes; and we’re also aware that some of us are live in urban areas which are connected to general sewage systems; if this is your scenario and having separate discharge lines in a long shot. Well then, let’s try these simple solutions for common causes of foul drainage odor.


The common presence of foul smells from drain can attributed to very small causes and sometimes major ones; we’re going to highlight every possible cause of foul smell to prefer a solution for it right after


This is a common cause experienced in a vast majority of homes using the combined system of discharge; water traps “which are bends, sags or other devices arranged in a waste pipe so the liquid content settles and forms a seal which prevents the escape of noxious gases but allows the flow of water” dry up to release foul smells coming from the sewage lines or coming from the dried up gunk in the trap into the house.

floor drain

The drying occurs as a result of not using that particular area frequently causing the water to evaporate and clearing a path way for the smells to creep in. water traps exist in various appliances; toilets, urinals, floor drains etc. and are very vital for preventing the release of noxious gas in your home; if you use a combined system of drainage.


  • Pouring adequate water down the drain to fill water trap and a little bit of cooking oil; it reduces the rate of evaporation.
  • Poor hot water; this act is not fully recommended because some pipe materials such as PVC cannot resist the effect of boiling water as it weakens the materials and its sealants but a smart way to bypass it is to use hot water but not boiling water; it’s still risky but it’s less risky
  • If its confirmed that smell is from the drain and its still persistent, follow the steps
  1. Sprinkle half a cup of baking soda into the drain and leave for a few minutes
  2. Mix one cup of vinegar to one cup of hot water, pour into the drain after the baking soda
  3. Cover the drain with a plug and keep it covered for about 10 to 15 minutes
  4. Flush one more time with a liter of hot water
  5. Top it off with a liter of cold water and about two spoons of cooking oil

After this, if foul odor still exists, explore the other possible causes below


The use of septic tanks for houses is still very common and it privatizes the disposal of the contained waste into structured units; but sometimes our busy lives make us forget that we’re supposed to have it emptied whenever it reaches a certain level.

When sewage reaches a certain level, the incoming wastes get stuck in pipes and further negligence of this will lead to the sewage accumulating and causing dreadful smells which may also damage the pipes if kept long enough; or if you do forget to clear out on frequent basis (mostly to PVC pipes). If you’re using a combined system of drainage, foul smells will come from the septic tank area, damaged/ leaking pipes and floor drains with no water trap.


  • Have septic tank emptied immediately, this will reduce the dreadful smell it causes
  • Having a schedule for emptying septic tanks is also mandatory and this should be done based the structure, capacity of the septic tank and the amount of people using it (please have your plumber calculate this for you), through that, a duration can be established and set as interval periods to which you have to empty tank no matter the circumstance. It could be 6 months, a year or two; you are to empty your septic tank between the interval period best for you.


Vents in plumbing are structured openings through which gases pass to escape into the atmosphere to release pipes from the pressure they may be subject to. The gases include the foul ones we’re trying to avoid so having them covered or blocked would require that they seek somewhere else to push through; and that’s why you might begin to get odors from places you don’t want to get them from in your home.


Blockage of vents for constantly used sewage pipes also proves to be very damaging to the plumbing systems because as the gases accumulate, they weaken certain elements of the pipe connections and even the septic tank, hence, the gases will break through and capitulate its plumbing structure eventually.


  • Check for vents to see if there are any blockages by having objects in them or by frozen blocks during the winter.
  • If you can risk the height (ensure you have safety gears on), get on a roof or ladder and clear the vent of any obstruction. During winter period, if your vent is covered by snow or ice and you have your air conditioning/heat pump connected to discharge pipes, use the vapor and condensate from the heat pumps to melt snow from vent or you can just pour hot water down the drain so its vapor travels up the vent to melt the ice.


Domestic sewage lines can be constructed either by being concealed or being exposed. By any means you choose, once they are constructed poorly there’s a high likeliness they will leak; and once this begins, foul smells will begin to dominate the air vacuum within the home and possibly its environment. The leakages atimes happen as a result of late emptying of septic tank if you have one. The contained waste volume and the presence of toxic gas pressurizes the pipe and as said earlier; if done frequently, plumbing system will capitulate and leak.

sewage pipe


  • Flush out the pipes and empty the septic tank if you have one.
  • Hire a plumber to examine and have a re-run check on the plumbing systems. (There’s likeliness that the part producing the odour is exposed, so you have little chance of having walls broken if pipes are concealed).
  • If leakage is found, the leaking joint should be checked to see if failure was as a result of excessive weight on the pipe, if it was due to weak fusion, cracks or leakage caused from internal pressure.
  • Have pipe restructured, replaced or re-strengthened.
  • After fixing, ensure drainage systems are frequently emptied at scheduled intervals.


During certain cases, the water itself is the cause of the odors you might have in your house. Contaminated water from general supply lines or from borehole can relay foul smells into the home making you think you might have a dead rodent somewhere; it’s a very rare instance in general but it’s one that occurs constantly in certain areas.


  • Have water treated adequately to clear them of bacteria causing odor in them
  • If you use or you are to utilize a borehole; ensure proper depths within the ranges of 150 to 180 feet below ground are reached to ensure proper clean water is drawn. You can get similar qualities at closer depth; it varies with regards to your area and its water table


Having little or no ventilations for your pipes are quite risky. The gases from sewage will be accumulated which will subject the pipes to undue pressure if they have no proper outlet into the outdoors. The gases can also be quite combustible especially if it manages to leak somewhere within the home.

Poor ventilation of pipes isn’t just limited to the lack of vents; it also refers to the poor installation of vents with regards to its position; having them in the wrong places and fixing them at shortened heights. All these in turn will cause the emergence of foul smells from various areas of your house.

Ideally, a 4” inch vent is ideal for the sewage system of a 4-bedroom apartment; your septic tank should have another specifically for it. Having numerous vents around the house is not necessary, but having just one placed perfectly and increasing its size with regards to the structure is mandatory.


  • Increase the number of vents within structure
  • Have a proper restructure of your vents; putting them about 2 feet beyond roof level (have your plumber check your house structure to determine what placements and heights are best for your vents).


Another cause of sewer smell from gents could be a bad wax ring seal between the toilet flange and the base of the toilet. This wax ring may leak occasionally, sometimes because of a moving toilet that has broken the seal. With a leak from this broken seal, the sewer gas will find its way out from underneath the toilet.


  • Toilet will have to be removed for wax ring to be replaced. If the toilet moves excessively, use plastic shims between the stool and the floor to balance the toilet and caulk the joint. This will ensure that a rocking toilet doesn’t spoil the new wax ring.