New Drainage Installations in Stockport
New runs for an extension, a chamber where there has never been access, surface water drainage that was never put in. Laid to the right falls, camera-tested before it is covered, signed off properly.
Get a second opinion before anyone brings a digger.
What we install
- New foul runs for an extension, a garage or loft conversion, or a kitchen moving across the house.
- Inspection chambers and manholes, including on runs that have never had access.
- Surface water drainage — channel drains, gullies and soakaways, sized against what the ground will take.
- Replacement runs, where relaying costs less than repairing the same pipe again.
- Rerouting and diversions, to move a run out from under where a building is going.
- Land and garden drainage, where the problem is ground water rather than a pipe.
We do not install package treatment plants. Replacing a septic tank with one is a different trade — the same answer as the septic tank page.
The three things that go wrong
- The fall. Approved Document H sets the minimums: 1:40 for a 100mm foul run, easing to 1:80 where the flow is high enough and there is at least one WC on it. Too shallow and solids sit. Too steep and the water runs away and leaves them behind, which is the one nobody expects.
- Foul and surface water mixed. New work has to keep them separate wherever there is a separate surface water sewer to reach — that is Requirement H5, and it is not optional. Tipping a driveway or a roof into a foul run is why older combined runs around Stockport surcharge in a downpour.
- Nobody told building control. New drainage serving a building is notifiable, and it has to be seen open and tested before it is covered. Backfilled first is the version that gets dug up again — or that a buyer's solicitor finds four years later.
How an installation runs
The digging is the visible part and the least of it. Almost everything that decides whether a new drain works happens before a spade comes out.
- 1
Find out what is already there
Covers up, camera down, existing runs traced and levelled. Where the new pipe ties in, and at what depth, decides the whole design. Occasionally it decides you do not need one.
- 2
Design it to the levels, not to the ground
Invert levels at both ends, the fall between them, pipe size for what is going down it, and where access goes so the run can be rodded and surveyed later.
- 3
Sort the paperwork before the digging
Building control where the work is notifiable, and a build-over agreement or a Section 106 connection application to United Utilities where the sewer is theirs. The final connection into a live public sewer is not something we do — United Utilities vet the contractor who cuts into their pipe and inspect the work themselves. Everything up to that point is ours, and we will say which is which at the start rather than halfway through.
- 4
Lay, bed and surround it properly
Granular bed and surround, joints made properly, concrete protection where the cover is shallow or a vehicle goes over it. A pipe crushed by its own backfill does not last, and it fails somewhere you now have to dig up twice.
- 5
Test it on camera, then cover it
Recorded before backfill, so you have evidence rather than an assurance. Keep the footage — it is what a buyer, a warranty provider or an insurer asks for, and it cannot be produced later.
Tell us what is being built and where
The extension, the conversion or the drive, and roughly where the existing drains run. That is usually enough to say whether you need new pipework at all.
Common questions
Does new drainage need building control approval?
Normally yes. Where it is part of an extension or a conversion, the approval for that work usually covers it and your builder is already dealing with it. Either way the drains are inspected and tested while still open — they cannot be backfilled first and shown afterwards. If someone offers to lay a new run without any of that, ask about it before you ask about the price.
Can I build my extension over an existing drain?
Often, yes, and it is not automatically a problem. If the pipe is a public sewer — which most shared drains and anything past your boundary became in 2011 — you need a build-over agreement from United Utilities, with conditions on how you build. If it is a private drain serving only your house, it is a matter for building control. The alternative is diverting the run around the new footprint, which is sometimes cheaper than complying. Price both.
Can the new drainage just be connected into the existing drain?
Foul into foul and surface into surface, yes, if the existing run has the capacity and sits at a level the new one can reach. Surface water into a foul drain, no. Where the public sewer is a combined one, United Utilities can allow it, but only where there is genuinely no alternative and the sewer has the capacity — their decision, applied for rather than assumed. Putting a new drive or roof into a foul run without that is a real cause of sewers backing up into houses in heavy rain. Plenty of older properties already have connections like that, which is a different matter from adding one today.
How deep does a new drain have to be?
There is no single figure, and anyone who gives you one has not looked. The depth is fixed at both ends — where the run starts and the level of what it joins — with the fall between them setting everything in the middle. What matters more is the cover over the pipe: a shallow run, particularly under a drive, needs concrete protection. It is why the existing chambers get lifted before anything is quoted.
Will you install a sewage treatment plant to replace my septic tank?
No. Replacing a tank with a package treatment plant is specialist work with its own design, commissioning and permitting, and we will point you at somebody who does it. What we will do is put a camera on the system first: a tank that needs emptying constantly usually has a failed drainage field rather than a tank that needs replacing.
What to read next
Drain Repairs
When a drain has gone beyond lining, it needs digging — properly, once, and put back the way it was found. Collapsed sections, root damage, failed connections and broken chambers.
Read moreSurface Water Drainage
Water standing on the drive, or running towards the house instead of away from it. Nearly always the fall, the soakaway or a gully that has been paved over — and it is worth finding out which before anyone lifts a slab.
Read moreCommercial Drainage Services
Planned maintenance and emergency cover for pubs, restaurants, care homes, letting agents and landlords across Stockport, Manchester and Cheshire. One engineer who knows your site, not a different subcontractor every time.
Read moreCCTV Drain Surveys
A camera down the drain, full colour footage, and a written report you can actually act on. Usually within the week — and if there is nothing wrong, we will tell you that too.
Read moreWhere we do this
New Drainage Installations across Stockport and the towns around it. Pick your town for response times, postcodes and the drainage we actually see there.