New en-suite soil waste into deep manhole

Discussion in 'Plumbers' Talk' started by hotnuts21, Apr 17, 2019.

  1. hotnuts21

    hotnuts21 New Member

    HI all,
    Im putting in a new en suite and this means a new waste pipe at the front of the house, we have a drain that runs directly under the house and into a manhole out the front of the property. Probably worth mentioning the house is 100yrs old and this is the original drains. They are also really deep at the front as the property is on a hill.

    A picture is always better than an explanation, so I have mocked up some drawings to explain what im planning, would be good to get some feedback before talking to BCO.

    Blue lines are suggested new waste pipe
    Red is the existing drain
    Yellow is the existing rainwater
    Green are access/durgo etc

    drains-main-view.png drains-front-view.png
  2. KIAB

    KIAB Well-Known Member

    hotnuts21 likes this.
  3. Geoffm1066

    Geoffm1066 New Member

    Is the manhole you wish to discharge into on your property? Easier task if it is as its your manhole whereas if its outside your property then who ever is in control of the waste water will need to issue a discharge licence for additional use. Either way you cannot enter into a manhole at the high point and drop down on the inside to the channel invert, you need to install a back drop pipe outside the manhole so the discharge is into the channel at invert level with a rodding eye at the high point.
    If as your drawing shows two side entry rainwater gullies then they were put in wrong as well, they two should be entering at the channel invert level from out side the manhole not half way up the manhole.
    If I'm wrong I'm sure someone will correct me.
  4. hotnuts21

    hotnuts21 New Member

    Geoffm1066 - Yep the rainwater gullies enter halfway up, but like i say they are original and were done long before building regs etc.
    The manhole is on the path, but I have been told its my responsibility which is a bit odd, it carries on before it goes into the main drain, its 'my' access to the drain, no one else discharges into this manhole, each house has its own.

    KIAB - Thanks for the suggestion, looks like im on the right tracks I had already looked at that page and thought about that, but from what I understand it would require the incoming drop pipe at the bottom to join the existing flow and the existing benching would need to be altered in the existing manhole? Im not sure its possible due to its depth, unless we remove the boundary/garden wall and dig up the pavement to get access to the bottom of the existing manhole and benching.

    Which is why I was looking at a drop pipe inside the existing chamber rather than outside it, but I haven't been able to find out if that's even possible yet. Seems like I might need to put a second inspection chamber in the front garden which drops down onto the main drain before it goes into this one, which I was trying to avoid.
  5. KIAB

    KIAB Well-Known Member

    Many years, since I dabbled with drop drains,probably still a few who use them,but times have move on,you would need to research whether it could be suitable.

  6. Severntrent

    Severntrent Active Member

    It is strange that you have been told that this MH is your responsibility especially if it is in the public highway which would mean that you would not be able to lay a drain into it without going through the necessary legalities. If you are in England/Wales the responsibility for drains outside the curtilage of your property passed to the Water Companies in 2011 and therefore you woudl not be able to carryout work on the MH but no doubt BC will appraise you of your rights (or lack of them?)
  7. ecoplumbing

    ecoplumbing Active Member

    How deep is the manhole? Backdrop is fine as long as there's access . I'm sure I read that internal back drops aren't allowed anymore, I could be wrong , but check with building control beforehand. Rest of the underground drainage- fall 1 in 40, long radius rest bend, access chambers if there's junctions or change of direction. Also noticed the durgo, is this internal or on the outside wall?
    KIAB likes this.
  8. hotnuts21

    hotnuts21 New Member

    Thanks all.
    eco-plumbing - the durgo is in the en suite so internal. We were going to have the waste pipe go up and vent from the roof side, however there is a window going in the roof quite high up so the soil would need to be even higher than the roof, so the internal durgo. I havent got as far as planning where thats going yet. Manhole is about 6 foot deep from the path, but its a tight space.

    severntrent - its possible the groundworks guy was talking Sh$$e. I suppose technically its on both lands, the access hatch is right up against my boundary wall and the brick chamber is partly under the same wall.

    Its looking more and more like I will need to drop down onto the existing pipe before it goes into the manhole. Shame that im going to need to have a manhole either side of the wall :-(
  9. KIAB

    KIAB Well-Known Member

    Intrested to know about internal drop drains whether they are allowed or not.
    ecoplumbing likes this.
  10. Severntrent

    Severntrent Active Member

    Never come across a MH half in someones land but prior to 2011 and notwithstanding the legal niceties it could have been your responsibility as it was on your drain to the public sewer. Responsibility now?? but as access is in public highway I would guess at water company. BC will be letting water company know about drainage issues so you may as well contact them upfront and discuss with them.
    KIAB likes this.
  11. hotnuts21

    hotnuts21 New Member

    I spoke to developer services at Welsh Water and internal backdrops are not allowed any more, would need to be an external one and would need to apply for a host of things if I connect it to the MH out the front. He said its best to connect into the main drain before it goes into the MH.

    So it looks like im going to have put a new IC and chamber in my front garden with an external backdrop. Sadly it looks like its going to cost most of the budget of the en suite! Thanks for all the help.

  12. Pollowick

    Pollowick Well-Known Member

    Can you not use a 300mm diameter plastic liner with a junction at the bottom? I had several installed here to connect new drain to, and divert, the old existing.
  13. Severntrent

    Severntrent Active Member

    If its on your property and only serves your drainage it has nothing to do with Welsh Water and I'm not aware of BC banning internal backdrops. Speak to BC.
  14. ecoplumbing

    ecoplumbing Active Member

    I read it on united utilities guidelines, it says ' generally internal backdrops are not permitted ' but I'm guessing that's just working on the main sewers or their drainage. So must be ok on private drains... i think! In my opinion, if internal backdrops are installed correctly then there's no problem. Saves a lot of excavation work
    KIAB likes this.
  15. ecoplumbing

    ecoplumbing Active Member

    Agree, utility companies don't control building regs so I'd check with building control. Might save you a few quid if they allow it in your own land
  16. hotnuts21

    hotnuts21 New Member

    HI all, thanks for the help. As the manhole is partially on the highway/public path just outside my boundary wall its been adopted by Welsh Water. So I need to connect into the pipe that runs into this. Just trying to find someone local who can do this now.

    Thanks for all the help.

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