Surface water drainage - please help!

CatLady87

Good evening,
I live in a row of terraces houses that were built circa 1870-1880. The previous owner started building an extension but stopped and left concrete foundations and two partially built walls in situ. As the surface was intended to be indoor, it naturally collects rainwater in puddles when it rains heavily. There is a small aco drain at the end of the would-be extension and this is fairly useless as the water that sits on the surface doesn’t drain into it and isn’t directed into it in any way. This has been a concern to me since I bought the house and I’ve finally found a builder willing to help me remedy this.

The builder has advised we dig down and fit another aco drain midway along the concrete and angle the concrete towards the aco drain and he will dig a trench towards the existing man hole and check the other aco drain drainage whilst he’s there. 

There is a section 24 sewer that runs along the back of the houses (along the right of way) and down the neighbour’s drive and that connects into a combined sewer on the Main Street. I can’t see any solely surface water sewers on the map I’ve got.

My question is this - can we connect into this via another aco drain? I can’t see that there will be that much water directed towards the sewer but I don’t know if I need to contact the water authority. He hasn’t mentioned I do and he said we didn’t need building regs for this kind of work, when I asked.

When I check my water Bill I’m being charged for surface and foul water drainage but the amount of surface water from my yard sits largely on the concrete until it evaporates or eventually finds its way down somewhere and the rest goes through the aco drain at the end (which apparently drains somehow though when I inspected it I couldn’t see where).

Many thanks

fezster

Technically, no. It wouldn't meet current building regs, which require a soakaway to be used.

However, many older houses use public sewers for rainwater, and I suspect many have been done this way after extensions or new driveways, for ease. Have a look at where your existing guttering is draining to and see if you can utilise the same drain.

CatLady87

Bummer. Sadly the downpipe is on next door’s property so that’s a no go

fezster

If you do decide to utilise the public sewer, make sure a P trap is used on the gulley, to prevent smells and odours from escaping it.

FreeBear

fezster said: Technically, no. It wouldn't meet current building regs, which require a soakaway to be used.

Building regs do allow for connection of surface water drain to a foul water sewer where there is no other alternative (Building Regulations, Part H3 para. 3.4 on p.45) - https://www.planningportal.co.uk/info/200135/approved_documents/71/part_h_-_drainage_and_waste_disposal

Planning permission may be required, so check with your local council before starting any work. Permission from the water company will also be needed in order to connect to the public sewer - Even if PP is not required, Building Control will still need to inspect and sign off the work.

CatLady87

Thanks folks. I presume a section 24 sewer is a combined sewer? In any event said sewer runs into a combined sewer, not a foul one of that makes any difference?

I’m a bit peeved the builder said ‘no’ when I asked about needing building regs. Worth looking elsewhere for another contractor? It’s taken me so long to find someone to take the job on, it all feels too much 🥺

Phil4432

Have to ask, didn't the surveyor pick up on this?  When you say "eventually finds its way down somewhere,"  that somewhere could be the foundation of your main building.  The surveyor should have advised you on this.  How long has the uncompleted extention been there?
Right now, I'd make your priority to get that rainwater away from your house.  Even a tarp over the base on the uncompleted foundations, angled so the rain water is directed away from the house.

CatLady87

Nope, not a word from the surveyor. The woman had fake grass on the concrete and surveyors don’t lift things that are fitted. I investigated the house so thoroughly when I bought (or so I thought) but I completed missed this clanger. But then again I’m not a surveyor or drainage expert!

The house doesn’t have foundations, the living room has a stone floor and the house is effectively built on the ground, or so I believe. The extension was granted Planning Permission in 2007 so some time after that. It was the owner previous to the woman we bought it off. She bought it in 2015.

Thankfully the puddles don’t reach the house from what I can see (at least not by the door anyway). It’s more in the middle and far corners of the concreted area.

Frustrating that I’ll need (or potentially need) water authority permission / PP for something with a solution that seems so simple!

CatLady87

I’ve checked the plans that were drawn up and are attached to the PP for the extension. They note that the manhole that is at the back of my house wasn’t directly connected to the public sewer and planned to move the manhole closer to my neighbour’s house. From looking at the plans it would appear the manhole cover was moved. Does anyone know if there would be a way to determine if the connecting a drain to the manhole would constitute connecting to the main sewer and if not, would this affect the need for PP and BRs? Many thanks

Jeepers_Creepers

Well, CatLady, I know what I would do in these circumstances...

If that's the only realistic solution, and if it'll do the trick, then I would tell the builder 'go ahead'. You seem to be paying for surface water drainage in your bills anyway, and there is no room for soakaways or anything like that.

I'm finding it hard to visualise the problem, tho'. What is the actual 'issue' - that the part-built extension fills with water? Can't drain holes be drilled in the end 'part' wall to allow it to escape to whatever is beyond there? Can it be gravelled to make it a gravel patio, deep enough to contain normal rainfalls which will then evaporate off as normal?

When the extension would have been built, where would the roof run-off go then? To that manhole you've seen? If so, send the water there...

CatLady87

It doesn’t so much fill with water as there are just puddles over certain parts of the concrete when it rains heavily. The water is never there for long though, which I find strange as there’s a damp proof lining around the bottom of the concrete. It mainly pools around the sides and occasionally near the window but I’ve not seen it at the back door before unless it’s exceptionally heavy rain (think a similar time last year when we had a monsoon-type storm).

I need to sell at some point in the next year and naturally (unlike the woman I bought off who was either unaware or covered it up) I don’t want to leave a buyer with this issue. Likewise I don’t want to cause an issue by doing something incorrectly, if that makes sense.

From looking at the plans, the intention was to build the extension (a conservatory I believe) and have guttering on it which would lead to the manhole. Someone has put the aco drain in at some point - possibly the person I bought off, but it doesn’t do a great job.

When you say you know what you’d do, what would that be?!