Drainage connection to mains sewer

[Tom10001]

Hi,

I recently had a very old interceptor trap removed. It was replaced with a straight run of pipe connected directly to the mains sewer. So my waste pipe is now connected to the mains sewer on a straight run, with no trap or interceptor.

Is this how it should be done?

Asking because my builder and a visitor from the council (pest control) were both very surprised that this is now the correct way of doing it.

I understand a straight run is going to give you less hassle in terms of blockages, but surely it's allowing rats to explore any weaknesses in your system?

thanks

 

[Hugh Jaleak]

Common practice now to remove interceptors if the need arises. They are a Victorian idea, prone to blockages and serve little useful purpose in many cases when the rodding eye above the inlet has long since disappeared and so renders the trap below completely useless.

There shouldn't be any weaknesses in a properly maintained drainage system, should rats be found exploiting any such weakness it is imperative the drain is made good to remove the fault.

 

[Tom10001]

Thanks again mate.

But when you say common to remove interceptor, you mean remove and not replace with any sort of trap at all? So it's supposed to be completely straight?

 

[Hugh Jaleak]

So it's supposed to be completely straight?

No, it needs slight fall on it, or it'll block...

Interceptors were a Victorian idea, introduced to seal off the house drains from the main sewer, (due to the fear of 'drain air' causing all the ills in that era), and were phased out eventually, around 1940ish due to their being so problematic.

Whilst at least one manufacturer still making salt glazed drainage pipes and fittings offers an interceptor trap, it is extremely rare to see any need or reason to replace one like for like. Building regs make no mention or any requirement, and they are deemed unnecessary in modern drainage systems, and in fact are frowned upon due to their tendency to block.

 

[Tom10001]

good to know, many thanks.