Moving a Sewer

[hansPulesh]

Hi all,

I'm looking to have a sewer manhole moved as per the attached plans. What is the process of this? How is this done?

Many thanks for your help.

Sewer Move

• hansPulesh
• 25 Apr 2015
• 1

The notes relating to the to the sewer move read as the following:

NEW MANHOLE: New manhole must be constructed of 215mm class B engineering brickwork with 150mm concrete base. Use cast iron frame cover to BS497. Dimensions of
manhole to be determined by invert level.
RAINWATER GOODS:
100mm wide PVCu semi circular section gutters laid to fall to discharge into 65mm diameter round rainwater downpipes.
PLUMBING INSTALLATION:
Complete installation to be subject to and cappable of withstanding testing in accordance with BS 5572 : 1978. Above ground foul drainage pipe work shall be PVC-u to BS 4514.
Pipe work must be designed in accordance with BS 5572 and installed to ensure that appliances drain efficiently without causing crossflow, backfall, leakage or blockage. No air
from the drainage system shall enter the building. Provide adequate support to lengths of pipework and at junctions and changes in direction. No branch connection to be within
450mm above foot of soil pipe. All PVC-u pipe work to be BS 4514. Minimum pipe sizes for sanitary plumbing to be:
WC's, soil pipes 100mm dia. nom. size
Common pipe wates 50mm dia. nom. size
Bath, sink 50mm dia. nom. size
Handbasin 32mm dia. nom. size
Shower 40mm dia. nom. size
Overflow 19mm dia. nom. size
All fittings are to have 75mm deep seal traps. Provide waste for washing machine and dishwasher where applicable. All waste pipes shall be laid to falls (25mm per meter run). All
plumbing shall be installed in accordance with manufacturer's instructions
The maximum lengths of waste pipes shall be as follows:
32mm pipe 1.7m maximum length
40mm pipe 3.0m maximum length
50mm pipe 4.0m maximum length
100mm pipe 6.0m maximum length
Soil pipes passing through habitable rooms (including kitchens) to be lagged with minimum 50mm sound deadening quilt and with two layers of 12.5mm plasterboard in
38mmx38mm softwood framing. Access and rodding eye fittings to be provided to ensure all pipework is accessible as required. Pipework laid between joists to be adequately
supported. Underground pipes with less than 750mm ground cover shall be insulated. All rising mains to be insulated.

UNDERGROUND DRAINAGE - ACCESS POINTS:
Access points in the form of rodding eyes, access fittings, inspection chambers or manholes to be provided at the following points:
(a) On the head of each drain run
(b) At a bend and at a change of gradient
(c) At a change of pipe size
(d) At a junction unless each run can be cleared from an access point
All new drainage to comply with BS 8301. New manholes to be propietary precast concrete type to BS 5911 installed in accordance with the manufacturers instructions or 225mm
engineering brickwork on 150mm concrete base, fit medium duty cover and frame. Internal size to be 450mmx450mm minimum for depths of 1000mm and under and
1200mmx750mm for depths greater than 1000mm. All incoming pipes to enter at half channel level and where pipe size changes occur lay with level soffits.
New drain runs to be 100mm diameter. uPVC pipe to BS 4460 and BS 5481 laid to a minimum 1:40 fall and bedded on and surrounded with 100mm of shingle.
All existing pipes near or under proposed structure to be exposed for inspection and repaired or replaced as necessary. Where pipes pass beneath any structure, surround with
100mm of granular material or similar approved flexible material, and place suitable pre-cast reinforced / concrete lintel over where passing through foundations with minimum
50mm clearance to pipe.
All disused drains to be grubbed up and removed or completely filled with concrete and sealed at mains.
All new gullies to be 'OSMA' type 4D.6900/901 roddable bottle gulliesm with grating or sealing plate if internal.
All existing drainage shown to be verified on site by the contractor prior to commencement of any works. Assumed drainage shown to be verified by the contractor, together with
determination of invert levels and direction of flow, all prior to commencement of works.

 

[Newboy]

The thread title and your first line are a little confusing.

Are you asking how to form a new chamber on an existing foul line or are you moving the foul run? (you plan suggests a new chamber location)

First (obvious) question - is the sewer is only serving your property?


Forming a new chamber is reasonably straightforward. The existing foul line is exposed and a section of the pipe removed, new chamber constructed (dependant on depth, it may be possible to use a preformed chamber rather than constructing a brick built one) the existing foul run is then connected to the new chamber. Remember that you will not be able to use the foul drain for some (or all) of the time the work is underway unless the sewer can be diverted to allow continued use.

It's also vital that the existing sewer is properly protected where is passes under (?) the new foundations and floor.

 

[hansPulesh]

Hi newboy, many thanks for that. the contents seemed quite technical and so before planning anything, I wanted to make sure that I knew exactly what the plans were advising.

Apologies, the title is quite confusing. What I wanted to know is, is it better to move the entire sewer run from where it is to a new location, or is it better to just leave the existing one as it is with a suitable cover and seal it and then construct another drain further in the garden and connecting it to the current drain/sewer?

From the plans, is either option available to me or should I choose one and not the other?
many thanks.

 

[bernardgreen]

From your diagram it would seem the sewer serves properties other than just your house.

The law changed a few years ago and any sewer serving more than one property is the property and responsibility of the water company even if it runs under you property.

You need to check with the water company whether the sewer can be changed or built over. The good news is they may do the work free of charge for you. The bad news is they may insist they do the work and charge you for it.

 

[Newboy]

First (obvious) question - is the sewer is only serving your property?

You need to answer this question BEFORE you start planning anything.

If it's a public sewer (serving more than one property) then you will need to gain permission from the water company to build over it, alter it or even touch it - if it's a public sewer then the water authority own it.

In the worst case, you can be made to take down a structure which has been built over a sewer without permission or, in the event that the sewer is damaged then you may find yourself with no extension and a large bill for repairing the sewer.

 

[hansPulesh]

It's actually a house owned by a friend and I've not yet been over to see the house or sewer as it is still occupied by the previous owner of the house.

Many thanks for your answers though, that helps a lot.

What does the water company normally insist on if it is a shared sewer and how much should be budgeted for this sort of work? House in is Greater London - Redbridge.

Many thanks.

 

[Newboy]

Impossible to say - to many variables.

Size of sewer/pipe type/condition/depth

Just for the record - it's a public sewer not a shared sewer (assuming that it is!)

 

[hansPulesh]

From your diagram it would seem the sewer serves properties other than just your house.

The law changed a few years ago and any sewer serving more than one property is the property and responsibility of the water company even if it runs under you property.

You need to check with the water company whether the sewer can be changed or built over. The good news is they may do the work free of charge for you. The bad news is they may insist they do the work and charge you for it.

Many thanks for this info. When you say water company, do you mean the company that supplies drinking water to the address? As this is a sewage manhole?

 

[bernardgreen]

do you mean the company that supplies drinking water to the address? As this is a sewage manhole?

Yes, in almost all places the water company does both.

Just for the record - it's a public sewer not a shared sewer (assuming that it is!)

It could be either. shared sewers serving several properties can be private until they reach the boundary of the public highway when they become "public".

The law changed to put private shared sewers under water company control because too many owners of private sewers shared by others were not maintaining them leading to other properties having problems with sewage backing up. They remain private sewers but will be maintained by the water company if necessary.

 

[Newboy]

https://www.ofwat.gov.uk/consumerissues/rightsresponsibilities/sewers/prs_web_sewertransfer

 

[bernardgreen]

I accept that shared sewers are now owned by the water company. But they are still under privately owned land and this causes confusion between "private" and "public"

I recently had a cracked concrete cover on a shared inspection chamber in my yard replaced with a steel one. During the conversations with the water company about the work the term "private shared" was used for the pipes under my land and "public" for the pipe under the public highway. Perhaps the term "shared service under private land" would be more accurate.

 

[hansPulesh]

Many thanks for the link - it's very helpful.

In most people's experience, what are water company reactions to this sort of thing? Do they kick up a fuss over moving/re-plumbing these drains/sewers? Or are they normally okay with it?

At a second glance on this topic, what parts would I need if I were to move the manhole or as suggested if I were to re-plumb the manhole with a second manhole for rodding purposes?

 

[Newboy]

To make it clear -assuming that the sewer in question is serving more than one property.

You cannot alter the sewer without the permission of the water company.

Works concerned with building close to (within 3 metres) or over a sewer are covered by Building Regulations 2010 Part H4.

You listed the parts you require in your first post on this subject!

If, as your posts suggest, you plan to do this work without gaining permission from the (probable) owner of the sewer then you are asking for a huge heap of trouble - assuming that you get that far without building control putting a stop to the project.

This may be of some help
http://secure.thameswater.co.uk/cps/rde/xbcr/corp/building-over-a-public-sewer.pdf

 

[hansPulesh]

No, not going to do anything without the correct consent etc, just need a list of materials so that I can work out a budget for the whole extension.

Went over today and had a look at what is going on.

There is basically a WC soil pipe which comes out of the first floor bathroom and enters the ground, concreted in place. This will remain in place and not be touched. There is a gutter/gully next to it, into which the waste water from the kitchen sink/washing machine go. This gutter/gully is what needs to be sealed.

The problem however is that the WC soil pipe and gutter/gully flows into the manhole (which was what I previously thought needed moving). This however is underneath the existing extension.

The question now is:

Would this existing gutter/gully be blocked and sealed and a new hole made into the sewer line running under the proposed extension into which a new manhole would be connected for rodding purposes? (Diagram 1)

Or alternatively, could I use the existing gutter/gully, connect a pipe to this and run that pipe to a new manhole for rodding purposes? (Diagram 2)

Or have I got it totally wrong and will it have to be done in some other way?

Untitled

• hansPulesh
• 26 Apr 2015
• 1

Untitled

• hansPulesh
• 26 Apr 2015
• 1

 

[hansPulesh]

...... Just thought of this idea, could I use a boss and use it to connect the new gulley into the WC soil pipe?