Is it possible to connect the kitchen wastewater to the downpipe?

Hello! I'm new here and I'm just going to blurt out right away:

Situation: Single-family house, detached, from 1935, repeatedly "renovated" by tenants, mostly unprofessionally. The kitchen is to be moved to another room. Is it allowed to connect the wastewater (sink / dishwasher) to the external downpipe (down into the basement and from there just below ground level into the downpipe)? I have to say that on that side of the house there is NO OTHER wastewater drainage. Bathroom etc. are connected to the sewer on the other side of the house!

I would be very happy about any info!
Best regards, Ally

I assume that by [Fallrohr] you mean the rainwater drainage.

There are municipalities where sewage and rainwater may be connected to the same sewer. In other municipalities, this is not allowed, and here sewage and rainwater must be disposed of separately. We cannot know what is permitted in your area; you need to inquire with your responsible authority.

Thank you very much for the information! I must admit that the situation already exists, but we have a problem: For about a year now, we have had a burrow in the front yard. We assumed it was caused by voles, but were proven wrong because it seems to be rats! Over the weekend, we held the garden hose into the burrow and it sounded strange, hollow... and the water disappeared immediately. We fetched a spade and carefully dug. About 40 cm below the ground, we found a "hose" (these ribbed black "hose pipes"), of course long broken, as you could tell from the "filth" around it. At first, we pondered, then I suggested our installed kitchen connection with downpipe (we had always thought it came from elsewhere). And lo and behold: it’s that. Clearly, there are rats there as well. Food scraps and dishwashing detergent residues... I don’t want to think about it! Our neighbor heard everything and told us that for them, the pure rain pipes end in drainage pipes in the garden and front yard, with some kind of "overflow" into the sewage system! Now we stand here not knowing what is down there. And from this situation, one wonders whether the plumber did everything right back then, or if he should have raised concerns??? For now, I’m the "stupid one." Now we’re considering: Since 2009, everything has worked (even in defective condition)! Should we just repair it? But: Where does it lead? Over the past year, soil has also been washed in: Is it slowly clogging up? Is it even allowed to use these ribbed black hoses (diameter 9 cm) for wastewater? Is it really a drainage pipe or hopefully a completely normal, i.e. closed pipe?? Questions upon questions.

Unfortunately, I am not very familiar with this. However, I would say that this hose is probably not suitable for that purpose. Possibly also not approved because it is far too thin-walled, maybe also for other reasons, but as I said, I am unsure about that.

Rats will now probably also like to use the pipe as a dwelling.

Yes, the pipe can also get clogged through soil.

There are such pipes with small holes in them to absorb and drain water from the ground, and then there are ones without holes. I cannot tell what you have there, but presumably it is without holes.

Have a professional come and take a look at it.

Personally, I would replace the line with a proper sewer pipe, which would also be laid deeper at the same time. Of course, assuming that it is ultimately possible to lay it deeper at your place.

Hello,

Situation: detached single-family house, from 1935, repeatedly "renovated" by tenants, mostly unprofessionally.
The kitchen is to be moved to another room. Is it allowed to connect the wastewater (sink / dishwasher) to the external downpipe (down into the basement and from there just below ground into the downpipe)?

No, this pipe is exclusively reserved for roof drainage.

I have to say that on the side of the house NO OTHER wastewater is discharged. Bathroom etc. are connected to the sewer on the other side of the house!

That can’t be; you just haven’t found another pipe yet. All wastewater was and is collected inside the house and then led out below the slab. Whether it then flows into one or two public connections depends again on the municipality’s regulations.

To answer your later question: No, don’t just "patch" it, call a gas/water installer and have all wastewater pipes renewed. Better a short painful end than endless torment.

Rhineland regards

Hello! Well, it really is the case that no other wastewater goes into this "pipe." It only comes from this one downpipe. And nothing converges under the house either, because before moving in we had all the wastewater pipes / sewers up to the street redone by a company (and we were mostly there). A soakaway pit and the old clay pipes were removed and replaced! All on the other side of the house. When flushing through our "pipe break," I was able to push the garden hose so far in there that it must already be outside the property!!! Of course, I prefer an end with a fright rather than a fright without end, but what matters to me is whether the plumber was allowed to do it that way? Of course, this pipe only starts in the ground approx. 40 cm from the point where he connected the kitchen wastewater to a normal KG pipe. So he did not see it, but he knew ALL the conditions because he also did the sewer work on the other side of the house during the renovation! And the house is old. As a local, he also knows that here. Should he have informed me? Should he have raised concerns? I am not a plumber and trust him with these works.