do I have a combined sewer?

[johnhenstock83]

morning,

 

I need a bit of help with my sewer, I'm not entirely sure if it's combined or not. the reason I'm asking is because we are looking to connect our extension downpipe (flat roof, approx 20m2) to it but as far as I know, that's not always "allowed".

 

I know the issue is connecting foul drains to a surface water one, not the other way round, but I believe they don't allow surface water into a foul sewer if there's a separate drain available.

 

we only have one sewer in the back garden (all neighbours do), so there's probably nothing for surface water, which leads me to believe it's a combined sewer. how can I tell for sure? the house was built in the 50s, ex-council terrace in surrey.

 

we have a downpipe at the front of the house, but it just hangs above the driveway. the ones at the back go into the ground, but I can't see where.

 

what will happen if I connect mine to the sewer? it's a small roof, can't imagine it will make any difference.

 

thanks!

[Redbeard]

To put it in context, think of all the recent coverage re storm water overflows leading to overloaded sewers and spillages. Yes, your roof is only small, but many many thousands of small roofs = a lot of water into combined sewers. I was surprised when I contacted my water authority (one of my fall-pipes draining approx 50m2 of roof discharges to soil with rock below) to be told 'yes, it's fine to connect to the combined sewer'. I realise that I have less chance of a soakaway soaking away than many, but even so...

[Carrerahill]

45 minutes ago, johnhenstock83 said:

morning,

 

I need a bit of help with my sewer, I'm not entirely sure if it's combined or not. the reason I'm asking is because we are looking to connect our extension downpipe (flat roof, approx 20m2) to it but as far as I know, that's not always "allowed".

 

I know the issue is connecting foul drains to a surface water one, not the other way round, but I believe they don't allow surface water into a foul sewer if there's a separate drain available.

 

we only have one sewer in the back garden (all neighbours do), so there's probably nothing for surface water, which leads me to believe it's a combined sewer. how can I tell for sure? the house was built in the 50s, ex-council terrace in surrey.

 

we have a downpipe at the front of the house, but it just hangs above the driveway. the ones at the back go into the ground, but I can't see where.

 

what will happen if I connect mine to the sewer? it's a small roof, can't imagine it will make any difference.

 

thanks!

Based on the age of your property I would suggest it will be combined, but do some checking.

 

Note, to avoid confusion, a soil pipe or drain, only becomes a sewer when it is a utility service serving multiple dwellings. People use the terms interchangeably and it can confuse matters quite considerably if people believe you are talking about a sewer, because in this case, you have no right to make a connection to a sewer, you would need the water board to give you a tie into their sewer. If it is your soil or rainwater pipe, then you can tie into it for various connections be it storm or foul.

 

[Temp]

1 hour ago, johnhenstock83 said:

morning,

 

I need a bit of help with my sewer, I'm not entirely sure if it's combined or not. the reason I'm asking is because we are looking to connect our extension downpipe (flat roof, approx 20m2) to it but as far as I know, that's not always "allowed".

 

I know the issue is connecting foul drains to a surface water one, not the other way round, but I believe they don't allow surface water into a foul sewer if there's a separate drain available.

 

we only have one sewer in the back garden (all neighbours do), so there's probably nothing for surface water, which leads me to believe it's a combined sewer. how can I tell for sure? the house was built in the 50s, ex-council terrace in surrey.

 

we have a downpipe at the front of the house, but it just hangs above the driveway. the ones at the back go into the ground, but I can't see where.

 

what will happen if I connect mine to the sewer? it's a small roof, can't imagine it will make any difference.

 

thanks!

 

Is it possible you have soakaways?

 

One option is to tip a dye into the gutter and have someone watch the inspection chambers.

[saveasteading]

2 hours ago, johnhenstock83 said:

need a bit of help with my sewer

It should be easy enough to check. Do you have manhole covers?

 

2 hours ago, Redbeard said:

, it's fine to connect to the combined sewer'. 

I do wonder if the drainage authorities really care.

If it is combined or separate, you can help by using a barrel. Firstly you can use it and it saves water plus reduces the drainage load, secondly it slows the flow to the drain, and reduces flash flooding. You can leave the tap on to drip away over the next day and be empty for the next downpour.

Every m2 counts.

[johnhenstock83]

right, some clarification:

 

1. I don't mean a sewer, I mean an inspection chamber. we have a private inspection chamber, where our private drains turn 90 degrees, and a public inspection chamber, just before draining into a main sewer. this inspection chamber collects stuff from all the houses in the row, including mine and has an interceptor trap. I can easily open this chamber when it rains, see if anything flows in there.

 

2. I'm not looking to connect directly into this final, public manhole, but have the downpipe drain into my private inspection chamber, from where my foul waste and flat roof water can drain slowly into an IC and from there into the main sewer, which is in the neighbour's (final house in row) back garden.

 

3. I'm thinking the same, I don't think the water authority cares either, but if I can do it by the book, I'd rather do it. can't be bothered to dig a soakway if it's a combine drain, the downpipe is literally half a meter away from the private manhole, it would take me 1 hours to connect it professionally, under the ground.

[saveasteading]

You lift the inspection chamber then one person inspects it while another flushes a toilet, with paper in it. Water hoes past and you know it is foul.

Repeat with water down a rainwater pipe, but no paper.  Water goes past and it is a rainwater drain.

2 positives and it is a combined system and you connect to it.

 

But adding a barrel to the new dp is a "good thing to do",  costs £30 and you save on water and sewage bills.

100 litres for the garden costs you about 15p and 20p for the sewage they assume results. 90 uses and you are winning.

Do you even have to connect to the drain? I don't know.

[johnhenstock83]

the problem is, the existing downpipes (at the back, front is a different story) are not in my garden, so I can't check much. theoretically, if they flow into the foul sewer (thus a combined one), I should see the flow, but it's a bit tricky until it rains. would calling Thames Water help or will they be useless as always, not even knowing what I have in my garden?

[saveasteading]

5 hours ago, johnhenstock83 said:

will they be useless

Even if they sent you plan , they are likely to be wrong.

 

You might wait a long time for heavy enough rain to see it flowing. But yes that will do it for you. 

 

What approx age is the house?

[johnhenstock83]

build in the early 50s.