Following my last post (earlier today) regarding the Bargara sewerage odour issues, I’ve received some kind feedback from a retired plumber who has been monitoring the Facebook thread. Thanks Pete!
He had experienced numerous similar complaints in the past and offered the following advice as a possible cause….
Apparently, about 15 – 20 years ago the plumbing legislation was amended and the requirement to fit a U-Bend water trap to every outlet (shower, basin, bath, floor waste) was removed. In its place, the new legislation only requires a U-Bend to be fitted below a basin and the primary (floor waste) discharge points.
The means that in the past the distance between the shower and bath outlets to the first (dedicated) U-Bend water trap was only a matter of centimeters. The new legislation now means that the distance from those outlets to the primary (floor waste) water trap has typically been lengthened to between one & two metres depending on the dimensions of the bathroom.
Here’s the critical point (as I understand it)…. Because the ‘fall’ in the level of the sub-floor piping is so negligible due to the confined space, there is a tendency for the usual yucky stuff like hair, dead skin, body fat, shampoo/conditioner chemicals, etc to gradually build up in the pipe over a period of many years. In the past, this would have collected within the water trap itself and could be effectively treated by chemicals such as Draino or Bicarbonate of Soda. Our friend advised that he had seen 50mm diameter pipes reduces to less than 15mm of clear bore due to the build up which gets worse and worse over time. This ‘gunk’ then sits in the length of pipe for many years through varying degrees of moisture and temperature changes and literally rots which creates the foul odour. In other words, it isn’t actually a sewerage smell but more of a contaminated waste odour.
There’s a product on the market called NilOdor which apparently can solve the problem by mixing just a few drops with a bucket of boiling water and pouring it down your waste water inlet points every now and then. I’m advised that Coles stock it but not sure about Woolies, the IGA or other stores.
I have no idea if this is what’s causing the problem in my home or others but it certainly sounds like a very feasible cause and would explain why, in our house, we don’t experience odours from our kitchen basins and ensuite with only a short length of shower discharge pipe but only from the larger bathroom. Our house was also built around the time that the legislation was changed. I’ll give the proposed remedy a try and post any results. If anyone else tries it, can you please also let us know if it’s solved the problem?