Sewage / drainage run to septic tank leaks. Best option to fix?

Hi,

I have a run from the house down to the septic tank which is around 60m long.
At the start of the run there is no liquid. By the time it enters the tanks, there is a steady stream of water which is generally clear and looks like you've left a hose on.

The pipe is 110mm plastic.

I've had it camera'd and it's not got a junction in it, has some "bellying" in it where it's full of water and clearly not a straight run (read: the ground has moved and it's moved with it).

My thinking, and the drainage guy, is that there are several small cracks in it which are allowing ground water to get in.
This makes sense as:
1. If I dig a 4ft hole, it turns into a well. We live on a moor.
2. In the manhole at the end, there is a small crack and it allows a steady drip of rain water in.


The drainage guy wants £11k to sleeve / patch it.
To me, if feels like perhaps he's pricing himself out of the job and not interested.

Question:
1. is my conclusion on ground water correct
2. Is the proposed solution the best one
3. Does the price seem corrct for it.


thanks.

That price sounds completely out of touch with reality.

If the soil is peaty or sandy and easy to dig and the pipe about 700mm deep then I would have expected about £30 per meter to dig a new trench. Then the cost of new pipe perhaps £35 per meter. But still not £183 per meter.

But it could be that the pipe used is not designed for underground use.

Many leaks in that kind of situation are caused by badly made joints.

Most would probably dig down to the pipe half way along and inspect to see if the leak is before or after that point.

Agile said:

But it could be that the pipe used is not designed for underground use.

Click to expand...

It's your bog-standard 110mm plastic pipe so assuming it is.

Agile said:

Many leaks in that kind of situation are caused by badly made joints.

Click to expand...

I'll go with this. I've already repaired one blown joint - you could see the seal hanging into the pipe.
Given that, and the run length, assuming the pipes are 6m lengths, and the pipe is not perfectly straight, it feels like there will be more blown joints.

To reline the pipe with patches feels OTT.

It may be bog standard to you but it could be anything to me.

I think that pipe designed for underground is usually UPVC and orangey in colour.

It costs less that £10 per meter but then a little extra is needed for transporting it to site and jointing it. And of course testing it before covering it.

yup, it's the orangey colour one.

And what is the soil and how deep?

My parents used to live in a house on sand and about 80m from the septic tank and I had some experience of pipework in that situation.

Cheapest quote was obtained by finding a man sitting in a JCB doing nothing who wanted to earn a little bit extra.

All clay and very soggy at the moment.

I've got another quote from someone who will jet it, find the cracks / popped joints and repair them rather than "line the whole pipe"....
Waiting on confirmation from him to come out.

to add -
the pipe runs diagonally under my lawn for most of it so really not enamoured with digging it up.

I wonder how he will find the leak.

My method would be to pull a plunger slowly down it until the water flow ceases.