Flood problems

[Ollie78]

Hi everyone, this is a bit of a non woodworking issue. But I am posting here on the offchance anyone knows what to do.

My house is effectively the "lowest" in the street and I guess the last drain before the main sewer. We have lived here 6 years now. When we get a powerful rainstorm the water will occasionally come back up from the main sewer and floods the driveway a bit or into garage floor which is about 100mm lower than the house. And I suspect under my hung floor. Luckily I have put in telescopic air vents when we moved in which stops it just flowing in.
This has happened very occasionally before, once every 2 years or so. However it has done it twice this year already, including today. It seems to be taking less rain to cause it now.

Last time the drain guys came they put a camera up and said my drains are fine, no damage internally etc.
I was going to put an aco/ french drain all the way accross the front on the house as my drive slopes down towards the house and bridges the damp proof layer (seperate but related issue) but if the water just floods back up the drain anyway this seems pointless.

If I install a sump pump or something I don`t know where I could pump the water to.

I guess I need some kind of drainage consultant to do a plan of action but when googling you get either drain unblocking firms or massive civil engineering companies.

I personally think this is a problem with Thames waters sewer system, not really my drains as such, but I don`t know what to do.

Any related experiences or solutions most welcome.

Off to sort out the garage

Thanks

Ollie

 

[Jacob]

Dig a big soakaway? i.e. deep pit back filled with stone. Bigger than this one and connected to rainwater gulleys sited as low as possible.

 

[RichardG]

You don't say how old your property is but you could argue that it's the responsibility of the local council / environment agency to maintain and provide adequate drainage. If the house (or estate) is less than 10 years old then there is still possible recompense from the builder. It will be a huge battle either way but as a longer term solution it would be worth keeping records of the flooding and writing to either or both parties every time it happens asking for it to be fixed.

Do you know the water table level, if not try and find out. If the water table is high then digging a deep soakaway won't help that much as it will just fill up from the water table. It will need to be shallow and large instead.

Another question is whether the foul water and surface water goes down the same drain? If not you could divert the water down the foul water drain, but of course that would be breaking the law so I couldn't possibly recommend it

 

[Sachakins]

We had a similar occurrences once in our street, but no damage to drains at house, got united utilities involved and turned out to be a cracked/damaged part of drain about 250 yards away around the corner. Not happened since repaired.

 

[Ollie78]

Thanks for replies

The water table is high and the soil is clay, we do get a large puddle or small lake in the back garden as well after a big storm, this however naturally goes away pretty fast and is not really the main problem as quite far from the house.
The house was built in the 1930`s so there is combined drainage. The issue is not really from the water collected from my property as such but more that it comes back up from the main sewer once that becomes full. It seems there is insufficient capacity in the system for a large storm.
I suspect the rain drains in the street also feed into the same line as well.

I have thought of adding a sort of surge tank or something to the system but there is no way I can afford this sort of thing, and really I think Thames water should be responsible as its not really my bit thats causing it.
The nearest main sewer manhole is at least 100m away in the next street and according to one neighbour very deep down.

Sashakins, I am hoping that it may be a case of damage somewhere down the line. This could be one reason it has become worse lately.
I have reported each case to Thames water so hopefully we can get at least some investigation going on, though they seem reluctant.

There is obviously some confusion about the drains around here as once a Thames water guy came and wanted to look in my garden for a drain that may or may not exist. Due to a problem a few houses up the road. They didn`t locate it.

Ollie

 

[Spectric]

that it comes back up from the main sewer once that becomes full. It seems there is insufficient capacity in the system for a large storm.
I suspect the rain drains in the street also feed into the same line as well.

This problem is becoming more common because they keep building houses and just connect them to the existing drains and hope they will cope, unfortunately they do have a limit on how much they can handle and this applies to treatment plants as well so under normal conditions they can just cope but add storm water and they have to just dump raw sewage into rivers. The local councils should be allowed to levy a utility tax on the developers which can be used to fund projects to upgrade these systems.

 

[Cabinetman]

Int

Thanks for replies

The water table is high and the soil is clay, we do get a large puddle or small lake in the back garden as well after a big storm, this however naturally goes away pretty fast and is not really the main problem as quite far from the house.
The house was built in the 1930`s so there is combined drainage. The issue is not really from the water collected from my property as such but more that it comes back up from the main sewer once that becomes full. It seems there is insufficient capacity in the system for a large storm.
I suspect the rain drains in the street also feed into the same line as well.

I have thought of adding a sort of surge tank or something to the system but there is no way I can afford this sort of thing, and really I think Thames water should be responsible as its not really my bit thats causing it.
The nearest main sewer manhole is at least 100m away in the next street and according to one neighbour very deep down.

Sashakins, I am hoping that it may be a case of damage somewhere down the line. This could be one reason it has become worse lately.
I have reported each case to Thames water so hopefully we can get at least some investigation going on, though they seem reluctant.

There is obviously some confusion about the drains around here as once a Thames water guy came and wanted to look in my garden for a drain that may or may not exist. Due to a problem a few houses up the road. They didn`t locate it.

Ollie

Interesting about the possibility of a drain in your back garden, it’s possible the manhole cover has been buried, it may be worth going over suspect areas with a garden fork. Ian

 

[Ollie78]

Interesting about the possibility of a drain in your back garden, it’s possible the manhole cover has been buried, it may be worth going over suspect areas with a garden fork. Ian

We had a good look as there is one indicated on some drawings from when we bought the house. There is a small circular patch of extra green grass that always grows a bit better than the rest but when I stuck a spike in there was no pipes or metal to be found.
Not sure if it would help much as the drains flow to the front of the house and the mystery drain is at the back behind the patio.

Thats the trouble with older houses I guess, there is always the archiology of trying to work out what the previous people did and why.

Ollie

 

[Sachakins]

Not just older houses, ours built in 1998, and the plans showed drain access to the rear and to the front of the property, with the front being a 10 foot by 8 foot deep expansion chamber, right under where drive was going, a major concern, but we wanted the house so went ahead.

Surprise of surprises when we moved in, both the rear water run off drain and the sewage expansion tank had both been placed over my boundry line onto the adjacent property. Go figure

 

[mikej460]

We had a good look as there is one indicated on some drawings from when we bought the house. There is a small circular patch of extra green grass that always grows a bit better than the rest but when I stuck a spike in there was no pipes or metal to be found.
Not sure if it would help much as the drains flow to the front of the house and the mystery drain is at the back behind the patio.

Thats the trouble with older houses I guess, there is always the archiology of trying to work out what the previous people did and why.

Ollie

An old soakaway is likely to be very deep so a spike may not find it. They are usually very deep holes filled with old bricks etc. then overlaid with soil.

 

[Blackswanwood]

Thames Water will be able to provide a plan of the drains and sewers that serve your property. The charge varies by water company.

If you are on clay it is unlikely that a soakaway will work. The flow of a sewer (or drain) doesn’t always correlate with the lie of the land.

I suspect that you will need a drainage survey to get to the bottom of it.

 

[baldkev]

Hairdryer?

Ok, ok, a serious comment then... how much are you willing to put in to jump start a resolution? If you were willing, you could hire a company to locate the rain water drain and feed a camera downstream to check it.... if they find anything, you can then get them to write you a quick report, which you can attack with. If there is a fault, look into the best way to lodge the complait / start a repair. It may be that a strongly worded letter stating that each time this happens it costs you money etc and any further expense will now be billed to them..... a solicitors headed paper would carry more weight....

If of course they find a fault.....

 

[Jameshow]

Could you sink a sump blue barrel? near the lowest point if your property and install. Pump and float switch in it and the discharge out onto the street so that when there's is excessive rain the pump kicks in pumps water away from your property?

Your french drain could drain into it?

I don't know your exact situation....

Cheers James

 

[Adam W.]

If it was mine I'd make some wire dowsing rods and take a walk around the garden to see what's what and get an idea if you have something like a drain out back.

I used them to find the gas main when the guy from the gas board couldn't find it, as it was very deep. Electricity is easy to find, as it has a very strong reaction, water and pipes are very easy too.

Quite how you're going to fix the problem is another matter though and a call/email to Thames Water would be a good option before going too far.

 

[Ollie78]

Thames Water will be able to provide a plan of the drains and sewers that serve your property. The charge varies by water company.

If you are on clay it is unlikely that a soakaway will work. The flow of a sewer (or drain) doesn’t always correlate with the lie of the land.

I suspect that you will need a drainage survey to get to the bottom of it.

Well they should be able to but i`m not sure they can, if so why did they send guys to randomly search our gardens. The drainage report from the time we bought the house was pretty basic, though interestingly did show the mystery drain in the garden.

There should be some guys coming tomorrow to clean up apparently. I will try and get them to put a camera down every drain I can find.

Hairdryer?

Ok, ok, a serious comment then... how much are you willing to put in to jump start a resolution? If you were willing, you could hire a company to locate the rain water drain and feed a camera downstream to check it.... if they find anything, you can then get them to write you a quick report, which you can attack with. If there is a fault, look into the best way to lodge the complait / start a repair. It may be that a strongly worded letter stating that each time this happens it costs you money etc and any further expense will now be billed to them..... a solicitors headed paper would carry more weight....

If of course they find a fault.....

Well it needs sorting out.
It is true to say that it is costing me time and money, its also nasty to clean up. I will see what happens next when they come tomorrow.
I am certainly willing to pay for a proper survey if I have to, though Thames water are quick to say that anything my side of the boundry is not their problem so I am inclined to think the reverse should also be true.

Could you sink a sump blue barrel? near the lowest point if your property and install. Pump and float switch in it and the discharge out onto the street so that when there's is excessive rain the pump kicks in pumps water away from your property?

Your french drain could drain into it?

I don't know your exact situation....

Cheers James

I was initially thinking about doing something like this as part of a solution involving an anti backflow valve. Unfortunately the amount of water we had this morning would fill a large barrel in about a minute. And the issue remains where to pump the water to so it doesnt just come straight back.
If I do anything it will involve digging through the concrete drive and over a meter down to get to the pipe so I will really need to design it all correctly and do it all at once.

Thanks to everyone for replying, it has cheered me up somewhat.

Cheers

Ollie

 

[baldkev]

Let us know how it goes tomorrow. Making the guys tea / coffees will help

 

[Cabinetman]

Don’t discount the Dowsing rods, till you’ve tried them it sounds like witchcraft, but they really do work and are surprisingly accurate.
Two tubes from bic pens as handles, two bits of wire, bent so that one bit goes down the handle and the rest is straight out in front of you, have it in your mind what you are looking for and walk up and down, when the rods move either across each other, or more unusually apart that is the point directly under your feet. Usually works best when you walk across- rather than along what you are looking for. Ian

 

[Sandyn]

I've had all the same problems at the house I am in. It has been a long running 'conversation' with the local council. When part of my drive at the back of the house was flooded with sewer water, They did respond and find the problem caused by a tree root partially blocking a main sewer at the rear of my house.

At the front of my house, I sometimes have water running off the road and flooding part of my garden. They come and do patchwork solutions, but never cure the problem.
The flooding happens at this time of year. Lots of torrential downpours and leaves blocking the drains on the road. The water then runs on to my property and down a drain for a down-pipe. No real damage is caused, but it shouldn't happen. My drain got blocked quickly with leaves. I made a new style of drain cover for the down-pipe which doesn't get blocked, (yet) so that problem has been cured.
They surveyed all the drains and discovered all the road drainage and half my house drainage goes down an old stone cundy dating from the 1850's. There is a main sewer running down the road, but they don't seem willing to put the road drainage into the sewer. The sewer is already at capacity, and they keep building more houses around the place, so it's probably best if they don't.
I haven't gone down the legal route with them, it's more an inconvenience and not causing damage. Councils are always very quick to threaten legal action if homeowners don't do something they want. I had trees obscuring a road sign. I was slow to cut them back (more than two weeks) they threatened legal action.
I now keep an eye on the drains on the road at the front and if they are blocked by leaves. I clear them. So far, My new cover has worked well. I should have done it years ago, but only when I retired did I get round to sorting out these sort of things.
You just have to keep pestering the local authority when flooding occurs. I take pictures and video, but perhaps sending them a bill for any clean-up work may focus their attention on sorting the problem.
Good luck!!

 

[baldkev]

Don’t discount the Dowsing rods, till you’ve tried them it sounds like witchcraft, but they really do work

I'm not saying they dont work, but about 20 years ago i was working for a builder and we were doing various jobs in a customers house. One day the customer asked if we could dig a small trench for him to find a pipe..... in comes a local old boy with divining rods, he wandered around until suddenly they moved and that was where we started digging.... after an hour we had a good trench but no pipe. Go deeper. Another hour and a much deeper trench.

The customer came out and said no, the pipe was definitely less than 2 foot deep. Another wander about and another crossing of the rods. Another trench. And so it went on until we hired a minidigger

The customer was convinced it had been in his driveway but the old chap couldn't find anything in there, so we dug across the width of the drive and about 2 foot down, on one side, bingo.


I'm sure they do work, but i believe they also pick up a lot of other things. In this case they failed to pick up that pipe.

 

[Keith 66]

Our local water company is Essex & Suffolk water previously Anglian, one of the problems round here is that the main sewers were lined a few years back so ended up smaller bore, then more houses get added on to the same network! Mass paving over of driveways so water runoff has nowhere to soak into the ground. Drains never cleaned, the one at the bottom of our road is now completely solid with earth & hasnt been cleaned for at least ten years. It used to be done annually.
We re did our driveway last year & found the house original soakaway & drain manhole under 12" of concrete huge bell shaped chamber, cleared it out a bit & laid new pipe to it & it serves well, we suspect it must be connected to the storm drain out in the road, My garage workshop is the lowest point in the garden & the driveway slopes into it, thus far no problems, dunno where all the water goes but it just goes so everything is good!