A hole full of smelly black water - Desperate for help and aa

[desperate]

Hi, this will be a long post please bear with me while I explain my problem........... I moved into my house about 10 years ago. My house sits at the lowest point in the street, the gradiant of which is very slight in deed, not reallly a hill at all just a little above flat at the one end of the street. It was apparent that there was a drainage problem as with each rainfall came a torrent of water running across the garden away fron the house under the fence at the end of the lawn and down my nieghborus very steep garden. They never complained once. The water always came from where my downpipe went into the ground, with each rainfall came a gush of water out of this drain about six inches high and always left a black sandy residue behind. However about four years ago the rain was so bad that the water level came witin half inch of my patio door. So I dug around the offending stormdrain to see if I could locate the problem....The problem was blindingly obvious my two downpies entered two drains beside my house and were never connected to anything just planted in the clay soil and that was the problem.....I contacted my insurers who promptly sent out workmen who agreed this was indeed my flooding problem. the reslove was to connect the the soakaway drains directly into the sewers which was about six feet away...........The next rains came and no flooding at all...yeepee.. After years, we could now landscape and take pride in our garden. I laid a sculptured decking from the house which went over the sewerage manhole and beyond. we rotivated and reseeded the lawn. around 8 mths later towards the end of last summer we started getting a smell from under the decking. My partner was convinced it was a dying rat or something simular as it did not smell like sewerage. The winter came and the smell seem to dissappear but now that summer is here again so is our smell. Thinking it could only be the manhole I took up the decking only to be shocked at what I saw..........
I am now the proud owner of a 3 x 2 x 2ft deep hole full of dirty jet black stagnant water. I have borroweed a sump pump this empties the hole which then refilles with clearer water when the water reaches it's level the water is again black and smelly. My local Env. Health officer has tested the water and it is just water, not sewerage. He also has put die in the surrounding drains but again it does not affect my black water. I have run a hose pipe down my stormdrians thinking the origanal job may have been bodged but the black water level stayes the same. Whe I pumped the water out secong time I realised the the water flow was coming from underground????? I turned a broom upside down and pushed it into the base of the 2ft deep hole to my horror and shock the 4ft broom handle went right in to the broom head. Tha is some 6ft of soggy soil right nest to my house and sewerage manhole. Severn trent say they have no water problems in the area and as it is in my back garden it is My problem anyway??? council say private house it is My problem??? insurers now say it is underground water rising, therefore My problem??? the council approved drainage specialist say they think and only think that because the seam on the manhole was not sealed properly the natural water table had risen to that point and then flowed through the manhole sides and therefore provided a constant flow of water underground, which has resulted in my hole in the ground. Everytime it rains there is a constant flow into the manhole when the rain stops the level drops and the water turns black almost instantly.... I have had a quote to install a 6ft deep land drain (sewerage juction sits 3ft below ground)next to the manhole with a silt trap and geotec membrane which would be tapped into the sewer..... I have no garden access, all works would be by hand, all soil would be carted through the house, as would all aggregate needed to make good again..my quote is for £1600. I do not know if this would solve my problem which apart from the water issure, there is of course the soft ground issue right next to my house. Any help/advise you could give would be appreciated as I do not know what to do.
Perhaps 5 or 6 six years of rain water washing around beneath my house would of coursed underground holes and chambers that has now appeared next to my manhole?? I really don't know. I am not sleeping through worry i won't let my kids play out in the garden and we all seam stay away from the back of the house.
agian sry for the long winded story but I think it is all relavant.


should I trust this quote please help me. Thankyou.

[flowjoe]

Might be worth having the water tested again just to confirm there is no E.coli present, i`m sure your guy knows what he is doing but samples have to be submitted within 24hrs and kept at a certain temperature or false readings occur. A good analysis will rule out foul water, ground water or potable water leaving you to concentrate on whatever is left.

The colouring and associated smell of the water is a little worrying, ground water doesn`t usually stagnate to that degree especially with the flow and movement you have described. There again your localilty may explain the colouring if you are local to a mining area.

Is the hole above a drainage system ?, ground that has been disturbed as part of a trench can act as a water course if not thoroughly compacted when backfilled, so it may only be a 6ft soft spot and not a disused mine shaft as i am sure you have imagined in the early hours of the morning

A simple land drainage system may well do the trick but i would be wary of installing any land drain this close to the house that is lower than the foundations, why go down 6ft when you are trying to keep water from hitting the surface.

There are numerous scenarios such as silted land drains, fence posts through original land drains and systems crushed as part of landscaping works. The trick is knowing when to stop throwing money at investigations and spending it on a solution. By the way the £1,600 quoted seems a fair enough price for the job described.

Hope this helps

[desperate]

hi Flowjoe, many thanks for a prompt reply. Amazing how just a few encouraging words of advise seems to lift a little weight from my shoulders.
The Enviro Health officer only did a test on site and concluded by whatever he did that it was not sewerage. I think he said he tested for traces of amonia?? does that sound about right?
I suppose the backfiiling could be a possibility.

As for the 6ft land drain, the drainage man said because the ground was so soft to that depth he would use that depth as the bottom of the drain and running the outlet from about halfway up as to run into the base of the sewer, the base of my sewer being only about 3ft deep.
The hole itself at the moment is about 2ft deep although when I have pumped out the pool of water there is a steady flow from a smaller 2" dia hole at the base, which is where I had stuck in the broom 4ft in, to see how soft the ground really was.

Although the immediate area shows no mines there are NCB workings with a mile radius but nothing too close. But that was open cast and long since gone.

My main confusion was the unexplained way in which the water comes through black almost immediately. Starts a little grey as it rises and then it reaches it's level and then turns dark grey/black soon after.


My one concern from your comments was the land drain so close to the house. The back of the house is single story then there is about 6 inches to the sewer manhole cover which is set on an angle, that would make the land drain about 3ft away from the back wall, spreading out away from the house about 3ft.

Just reading about your scenarios......from the rear of the house to the back fence is about 30ft. Just beyond the fence and about a 6ft drop on steep gradiant are houses that were built just one year before I moved in to my house. I suppose it is possible that an origianl soakaway/landrain could have been damaged, removed or disturbed.

Once again thanks for your advise I feel a little happier now I have read your reply. I will check again tomorrow for any other replies.

Thank you. Mark

[matt h]

blackening often occurs when you have detergent in the water it also pongs to high heaven if you have to dig it out:( could your waste water drain be damaged and weeping into the soil? wouldnt be the first time its happened:rock:

[desperate]

hi matt, thanks for the reply, that sounds exactly my problem. Trouble is I am reliant on the local Pro's to advise me. My garden has been dug up once as in my initial post because the origihal builders did not put my rain water drains into anything at all, there were two house bricks lay in front of the outlet..... that was sorted a couple of years ago by piping them into to the sewer. I have tried the obvious ways of detection....releasing bath full of water, while the dishwasher, washing machine is on and the toilet being flushed, running water down my downpipes..etc..etc.. all of these never alter the level in my new water feature. I have had various drainage companies out to give me advise but none of them have a clue. The only thing that alters the level is the rain.. but as you say in your post, my water comes through black and very smelly....Thanks for your time...

Mark

[flowjoe]

Desperado

You don`t have a neighbour with a septic tank do you, the colouring you describe is often found in leach fields and soak-aways (septic) systems.

Having said that you environmental guy should have found traces in the water sample.

It sound like soil erosion due to ground water finding its way into the adjacent chamber or is it possible that the sewer surcharges occasionally and fills the chamber polluting the surrounding sub-soil before the level drops washing away some of the said sub-soil ?

IYKWIM

[matt h]

would suggest dig out black stuff and follow it to broken pipe dig out and repair otherwise you will get more problems than you,ll be wantin imho:(

[seanandruby]

Would advise against going in manhole without confined spaces set-up. with that kind of smell it could be potentially dangerous.

[desperate]

hi all,

Flowjoe has hit the nail on the head by saying that the black water is indeed finding it's way into the adjacent sewer manhole which is made up of rectagular sections. The top section is not sitting quite square on the lower part hence the black water level when it rises, does flow away into the sewerage drain.

As for the chamber filling and spilling out the other way...I don't think so I have now had the decking up for over two weeks and have been monitoring the problem daily. Even in heavy rain the manhole chamber has a constant flow with no blocking at all.

Matt H ...I would concider digging down to find the problem but as already described all the tests on my house have not altered the level. Therefore I can only conclude that the leak is from one of my nieghbours somewhere.....
Keep your eye on the news...
Man digs up whole street to find smelly water source..Lol.

Seanandruby...
Seriously though I have about six foot of slushy ground a foot away from my footings I am not happy digging down that far with the house above me.

thanks for your advise.

mark.

[desperate]

Update ....


No rain now for 5 days, every night i pump out the black water. Next morning the hole is full again...?????

[flowjoe]

Sounds like a constant flow of foul waste to me, have you had the water analysis redone yet?

[Dave_L]

No rain now for 5 days, every night i pump out the black water. Next morning the hole is full again...?????

Does it smell of foul water?

[matt h]

cant you excavate a bit towards your neighbour to see if its coming that way?d

[seanandruby]

Had simular at heathrow. Some machine driver fractured a 150 soil pipe coming from the virgin airline lounge. Weeks later the smell started so i was sent to investigate. the ground outside the pipe was washed away and replaced slowly over the weeks with s**** Had to do a ghoster to repair it which turned into 3 nights. Then i rodded up the inlet to the back drop and only just got out of the manhole in time, the smell as the stuff stuck in the pipe moved, had me and the top man gagging. not nice, i sypathise with you m8.

[desperate]

hi all, sry I have been away for a couple of days, upon my return I hoped that the pixies had fixed the problem but alas it is still there..lol

The water has again been tested but again only for tracies of foul...as before there is no trace. I am wondering where I could get a sample tested to see exactly what is in the water.

I have neighbours either side and the hole is smack in the middle of my garden..I think I will have to start digging some more.. although when I pump out the hole the flow is from the base of the hole and not from one particular direction.

once I have had the chance to dig around I will post again my findings..thank you all for your time.