Question regardi g a manhole cover

[markblue777]

Hi All,
A bit off topic from woodworking but wanted to know peoples input on this.

Looking to do a porch (and later on a side single story extension to the house) and wanted to know about foundation depths for digging near this and if i need permission from thames water before digging anything.

The man hole cover, is anything identifying this as private (my responsibility) or thames waters duty to repair (it has a rust hole and the concrete collar around it is breaking up and falling away in fair sized chunks)

Under the cover it looks like this. After looking at it just now with a stick the top right is the only hole that is open and that is where the toilet waste comes from. So all other ports are sealed (plastic casing blocking them)

The sewer runs left looking at the drain (passed our front door and the house into the street)

help appreciated.

Cheers
Mark

 

[gav]

The water company is only responsible for maintaining sewers on private land where they service more than one property. So if only your waste passes through it, its yours to maintain.

see http://www.ccwater.org.uk/waterissues/currentkeywaterissues/privatesewersandlateraldrains/

 

[markblue777]

yeah from what I have seen, it does seem to be my responsibility. (bonus for coming to extensions and that as I dont need to pay £500 to get permission to build near it)

 

[swb58]

Looks like there's a bit of blockage there somewhere.

 

[markblue777]

Why do you say that swb? Just looked at it a bit ago and it is clearer now (the water at least and can see the bottom). I think it was because I just washed out the soil that was in the pipe

 

[swb58]

Sorry if I jumped the gun saying that but water shouldn't be standing in a drain. If it was moving away slowly and was clear (as in gone) soon after that's ok.

 

[markblue777]

Ah right ok no probs swb. May borrow my uncles dyno rods and sweep it through just in case

 

[RobinBHM]

Generally you need to go min 150mm below invert level. That way any foundation wont exert pressure on the pipework.

 

[Lons]

Generally you need to go min 150mm below invert level. That way any foundation wont exert pressure on the pipework.

+ 1
Exactly right. I have a diagram somewhere that illustrates why.

As an aside, if you are considering draining a rainwater gutter from your new porch into that system be aware that if you currently have a separate arrangement for foul and surface drainage you may contravene regulations by so doing. Doesn't matter that the system is on your land as it still connects into a common sewer which is the responsibility of the water authority.

cheers
Bob

 

[Phil Pascoe]

Looks like there's a bit of blockage there somewhere.

That doesn't necessarily follow - I had one that always held water, it wasn't blocked at all but the manhole was in soft ground and had sunk slightly.

 

[No skills]

Generally you need to go min 150mm below invert level. That way any foundation wont exert pressure on the pipework.

+ 1
Exactly right. I have a diagram somewhere that illustrates why.

As an aside, if you are considering draining a rainwater gutter from your new porch into that system be aware that if you currently have a separate arrangement for foul and surface drainage you may contravene regulations by so doing. Doesn't matter that the system is on your land as it still connects into a common sewer which is the responsibility of the water authority.

cheers
Bob

If you have an older house you might be lucky with both types of waste water going in the one drain, that chamber looks pretty modern though. Ive got to move my soil stack before I can do my porch, a job I'm so looking forward to...

 

[Phil Pascoe]

My mother had a small kitchen extension built, and the foundations had to go down nearly nine feet because of the drains. The groundwork cost as much as the extension.

 

[Lons]

If you have an older house you might be lucky with both types of waste water going in the one drain, that chamber looks pretty modern though. Ive got to move my soil stack before I can do my porch, a job I'm so looking forward to...

yep, I did say " if ".

There are arguments for and against a combined system. the pro is that increased water flow can help keep the pipes clear but the downside is that debris enters the system and causes blockages.
It's amazing how often householders route land drains straight into systems and cause problems further down the line.

As an aside, apart from the obvious blockage culprits such as sanitary towels and nappies, one of the chief causes is dental floss which shreds, catches and is horrendous to remove so tell the kids to put it in the bin, not the bog. (hammer) :lol:

 

[Phil Pascoe]

Swmbo laughs when I wipe out oily pans with kitchen paper before washing them. I cleared too many blocks of fat from drains in my previous life. :roll:

 

[No skills]

For a few years, every time my neighbour had a party we would end up with a block drain :evil: :evil: :evil:

Baby wipes an all sorts seem to get stuffed down their toilets, bloody horrible to sort out. The last time it happened I rodded a bit further than normal and hit something solid or a ridge of something. Gave it a good bashing and have been luckily free from blockages for a couple of years now.

 

[Lons]

Swmbo laughs when I wipe out oily pans with kitchen paper before washing them. I cleared too many blocks of fat from drains in my previous life. :roll:

Mine used to be the same Phil but she does it now :lol:
Reason I know about the dental floss is because we had an issue years ago which took a lot of horrible work to sort and that was the cause. Co-incidental conversation with a couple of building inspectors on a subsequent job was very enlightening. Needless to say, my missus doesn't put floss in the toilet anymore 'cos I said she would have to unblock the drains if it happened again. :wink:

I lift the manhole covers at least once a year and blast them though with a pressure washer, do the same with all the downpipe rainwater traps regularly which stops any build up.

cheers
Bob

 

[dickm]

Swmbo laughs when I wipe out oily pans with kitchen paper before washing them. :roll:

But if she doesn't wipe oily pans with kitchen paper, what does she use for firelighters ?
(I've been told by a chemist that you shouldn't wash non-stick pans with detergent anyway)

 

[Phil Pascoe]

Dishwashers certainly do them no favours. I never wash my bread tins or omelette pans.