Plumbing....philosophical question

[Mosaic]

Just gaving around the backs of the houses round here...can anyone explain to me why some houses have bathroom drains from the washbasin / bath ythat go into an open hopper, then down the spout?
Why not connect all your drains to the one poo pipe?
Would it cause a terrible methane explosion?

[Mosaic]

Typing prob's again - this time a teeny tiny keyboard vs fingers like half a pound of cumberland sausage.

[bookbinder]

I believe that it's something to do with drainage regulations. Sewage has to be kept separate from rainwater and/or bathwater, or something like that.

[Mosaic]

Rainwater I can believe but not bathwater and poo water, as the former is relied on to wash away the latter in the sewer.

[Mosaic]

Doc your method is what seems logical to me. I'm gazing at these older houses, and there are some mazes of pipes criss crossing some of them which would be much neater done your way. They are very unsightly as ythey stand. Not that it's any of my business, I'm just nosy.

[Frank97]

Is it something to do with smell coming back up the poo pipe into the bathroom, ie the bath and basin don't need a u-bend?

[Mosaic]

Well my baths and basins have a u-bend - or is it an s-bend.....so smells couldn't get back up them....

[Old_Geezer]

I hope your bath/basin has an air trap !

[Mosaic]

I'm still not havin g the open hopper arragement explained - come on guys, share the secrets.....

[Old_Geezer]

That's the trouble with philosophical questions. It may be no one knows the answer. Maybe the answer is just a pipe dream.

[Frank97]

Where's the builder when you need him?

[Mosaic]

Aah Doc....so this is what a 'waste manifold' would do nowadays, but was not available in the cast iron age.
OG what's an air trap?

[bentaxle]

I would think its an air gap to seperate sink and bath water from foul drains as it could contaminate drinking water

[The Builder]

All waste water (not rainwater) is "soil". Today it would all go directly into a soil stack, and then to the foul drain. Hoppers are just a very old-fashioned system. No problem with methane, Mos, because it would be vented. :o)))

[Mosaic]

Thanks to all of you for replying, and to TB for explaining the hopper / methane explosion issues, I can now rest easy.

[Whickerman]

It's a more fundamental reason - if you get a blockage, it pours water into the yard, not back up the pipes to the bath/sink.