Kitchen drain pipe question

ovbg · Apr 13, 2011

Hello, I am writing here despite being in Germany because my German is still not good enough for this, so I am hoping one of you guys can help.

My wife and I have bought a new build apartment (still under construction but only a couple of months away from being finished)

The question is regarding the lack of a slope in the kitchen sink/dishwasher drainage pipe. From the sink, the pipes drops to the floor level, where it has a 3.2foot (1meter) length, then a 90° turn, then another straight 18foot (5.5meter) length before it reaches the main pipe where it drops out of the apartment.

This length of pipe is flat on the floor with no gradient outside of the drop from the sink.

I have been told that this may be an issue with smell and run off. For smell, it was suggested to have a ventilator filter of some sort.

My question is, could this length really be a problem with runoff? The pipe is 2inches (5cm).

Regarding the ventilator (Air Admittance Valve, AAV), will this assist in smells and runoff in any way? I am guessing this device connects under the sink somehow.

Due to the type of building and the construction company, we have very limited choice in what we can do with this pipe. It can not go inside the support wall etc. If it needs a larger gradient, it would mean we would have to incur large costs on our kitchen installation which we don't really have the funds for any more, so I am hoping that that step is not needed.

Thanks in advance for your help :O)

plumberdarren · Apr 13, 2011

Im afraid i know nothing about german regs but surely if there is no drop and doesnt function correctly the construction company should rectify it??

ovbg · Apr 13, 2011

Thanks for your reply plumberdarren,
At the moment, the apartment is still under construction and the plumbing has been completed. As we do not have our kitchen installed yet, we do not know if there will be a problem. My question is hopefully to prevent one. I have read that there should be a gradient/slope, but in our kitchen there is not one. It runs flat for 6.5meters. The builder is a large company (Hochtief, one of the largest in Germany) so I would naturally assume they know what they are doing. But something seems not right about this. If there is going to be a problem, I would like to know if there is a cost effective solution we can implement before the kitchen is installed to save us an enormous cost later.

pobsdad · Apr 25, 2011

Was that an advert for Drain City Plumbers,by any chance?
I can see why your plumbers are using 2" pipe.Even running level it is likely to work fine till the warranty expires,but it will probably cause problems eventually.The problem is that you can't always get a decent fall in the kitchen because of appliances,etc.

Gray0689 · Apr 25, 2011

The 2inch pipe run level will work with no problem at all

paulnwales · Apr 25, 2011

german regs are much more strict than ours from wht i can gather.

kay-jay · Apr 26, 2011

if the pipe runs directly down from the sink then runs along floor level, simply shorten the length of pipe from sink to floor by an inch and there you have it ....instant self clearing gradient! just remember to move the clips on the horizontal run.

its so easy you can do it yourself in 5 minutes before the rest of the units get installed.

KJ