Finding a soakaway

[Bert Coules]

Somewhere under my back garden there's a soakaway pit, fed from a gutter downpipe. I'd like to run a second feed to it from guttering newly fitted to my garage, but I have to find it first. The garden is undeveloped, just poor quality grass over a barely-leveled area of ground, so can be dug up with no problems - but is there a method for locating the soakaway?

In the very centre of what passes for the lawn is a roughly square patch of concrete some 12" x 12" with what looks like the base socket for a circular dryer at its centre. I suppose there's a possibility that this was done when the soakaway was installed, so perhaps that's a reasonable place to start looking. Or perhaps I should wait for rain and employ a water-diviner...

[David.WE.Roberts]

How old is the property? Age + building regs should tell you the minimum distance from the house.

Best method?

Binary chop?

First dig down where the house downpipe is and locate the underground pipe going to the soak away - expose enough to find the line of the pipe run, then peg a cord out along that line.

Dig down about 3 metres out along the line in a long narrow slit trench at right angles to the run, until you either find or don't find the pipe.

If you find the pipe, go out another 3 metres.

If you don't find the pipe, come in 1.5 metres (that is halfway between the house and the 'lack of pipe').

When you have established a segment along the line where one end is 'pipe' and the other end is 'not pipe' then you dig another slit trench in the middle of the section - 'chop' the section in half.

Repeat using the ever smaller segments until you find the soakaway.

Allegedly more efficient than just digging a slit trench every metre along the run, or exposing the complete pipe run.

Have fun.

Dave R

[Bert Coules]

Dave,

Thanks for that. The building is early sixties: I'll check about the minimum distance. I'll also look to see if the location of the soakaway is marked on the deeds: I suppose there's a chance.

Your "binary chop" approach sounds sensible.

Bert

[Tim Watts]

Either:

1) Buy a cheap waterproof chinese webcam on a 5m USB cable. Push down pipe and see which direction it goes and how far.

I've done this...

2) Stick the hose down it and use a listening stick to find where on the ground you can hear running water. I have not done this.

[Bert Coules]

I can see how that could determine the distance, but how could I tell the direction?

A listening stick presumably being something you hold to the ground at one end and to your ear at the other?

Thanks for the thoughts.

Bert

[JimK]

Dowsing rods?

Jim K

[Tim Watts]

Well, that is tricky... But it will tell you if you have any bends in the pipe.

You should be able to estimate the starting direction when you see how the cable goes down the bend.

A test hole near the start should confirm the direction accurately enough to make a good estimate of the far end if it is a straight run.

Indeed. The water companies still use them.

I guess this is really going to depend on what the ground is like as to how well the sound comes through. OTOH a rounded end metal tube mop handle might be worth a go and you might have one you can pull off a mop for a test.

[Tim Watts]

Hazel twig or pair of bent coat hanger wire in biro tubes?

[Bert Coules]

I'm perfectly happy to try a spot of dowsing, but when there's enough water in the soakaway to make it detectable, isn't there likely to be quite a lot of water all over the place anyway? Won't my bent bits of coat hanger get confused?

I suppose I could run a hose up to the gutter...

Bert

[Tim Watts]

Oh - so you don't have an open access point at ground level?

[Bert Coules]

No, the downpipe just disappears into the ground.

Bert

[PeterC]

An inspector from AW, trying to find a leak in my supply, used a solid stick with a metal point (blunt cone, not sharp) at the bottom end and a sort of very shallow cup for the top. A tube seems logical, but it gives the 'seashell' effect, so if the leak or sound is faint you hear your own blood circulating (if you don't, the position of the soakaway is no longer relevant!).

[JimK]

Hazel twig or pair of bent coat hanger wire in biro tubes?/q

The latter are easier to fake with....:-)

Jim K

[Brian Gaff]

I suppose they used plastic papes then?

Brian

[Bert Coules]

I don't know, Brian. Early sixties, so I suppose it's a possibility. I'm going to have a tentative dig at the base of the downpipe and see what I can unearth.

Bert

[JimK]

/Tim Watts

- show quoted text - Either:

1) Buy a cheap waterproof chinese webcam on a 5m USB cable. Push down pipe and see which direction it goes and how far.

I've done this... /q

Gotta link to the USB camera plse?

Jim K

[Andy Burns]

How do you keep track of which way up it is? I suppose a trickle of water should give a clue ...

[Tim Watts]

Something like:

Search ebay for "5m USB camera" or "Waterproof USB camera".

Often from China, which is OK if you can wait 2 weeks for delivery. The above claims to be a UK seller.

[Bert Coules]

Thanks for the link. I just ordered one, and the estimated delivery date is next Tuesday.

Bert

[Tim Watts]

Basically, yes...