Testing drains with drain bung (sewer)

[David Angel]

Whilst selling our house, our buyer paid a chap to test our drains. The report claims that we have a leak in our drains (although I have not seen it yet) and our buyers are now asking to ahve £500 knocked off the cost of the house. Our drains are incredibly simple and join into next doors land, so if there is a leak it may even be there. A friend tells me that all they do is put a bung in the pipe where the drain meets the road and then fill it with water and see if it goes down. Is this true? If so, can I buy one of these bungs and test the pipes at various points myself? If so, where can I get one?

Thanks

 

[Andrew Bodenham]

Drain test kits can be hired from good hire shops, e.g. HSS.

I'd insist on having a copy of the inspection report, and checking out the company / individual who performed the test.

£500 is not much for an unspecified 'drain problem'. If there is a serious leak it could cost a lot more to rectify. So you could cut your losses, make the reduction and hopefully get your sale. Then again you may not wish to give in to dubious nit-picking by buyers trying to shave a few pounds off the deal.

 

[Nemesis]

I'd certainly ask to see the report - and the qualifications of the person carrying out the test...

 

[David Angel]

Thanks all. Yes, I have asked to see the report and will take it from there.

 

[geoff]

You are lucky they only want £500. When I sold my previous place eight years ago in Hampshire, a 'specialist drainage' company (look out for stetsons and horses....) who checked out the septic tank claimed there was a slight sag in the joint between two pipes in the (40 foot) run to the septic tank. This was two foot down under a grass lawn area. They quoted £3000 to fix it - just to fix the sag! I think even the purchaser was embarrassed by that. I didn't drop the price and just pointed out that the local builder would take an hour or two to fix it including yawns, coffee and fag breaks.

 

[Nemesis]

A friend who sold her Grade II a few weeks' ago had the purchasers, well into the sale process, come round with a builder to 'look around' - ie try every way to drop the price.

They went into the basement, which was once the kitchen.

Earholing at the top of the stairs, she could hear them asking the builder for his 'opinion' that the place needed to be tanked and of course the price hugely reduced...

Thankfully he was an honest man and said that the basement was sound and dry and tanking inappropriate.

However, it's becoming more and more common.

Why, you wonder, pick on the drains to investigate?

 

[middi]

This sounds like a " trick of the trade" scam to knock a bit more money off.

Go to any builders merchants, buy a test bung for a fiver, fill the drains yourself and see if the level falls within half an hour or so.

If it does, happily reduce the sale by £500.

 

[Andrew Bodenham]

They pick on drains because for most people they are out of sight, out of mind. A proper inspection requires specialist equipment, so it's unlikely that even a keen DIYing vendor could easily argue with the findings of a "specialist" survey without running to the expense of hiring in an inspection kit.

Also there's a touch of the unknown about drains. Only the keenest DIYers will ever carry out serious below-ground drainage works, and then only when doing an extension or major renovation. Most householders haven't a clue about what happens when they pull the plug or flush the loo. So drains, above all else, are ripe for exploitation. Runners up include anything in dark, inaccessible places (woodworm in attics) and anything invisible (damp, esp. 'rising' damp). Oh, and radon.

 

[Stephen]

This is what is commonly called 'pressure testing' and that is the problem.

The idea is you put a drain plug in one end and fill it with water, stand back to see if the waer level goes down. If it does you have a leak.

The problem is that it puts the drain under an abnormal pressure that it would not normally be subjected to and could (rare admittedly) cause damage to an old weak drain.

The other problem is that drains can have fine cracks and still function perfectly adequately under normal conditions. Sometimes the crack could be in the top of the drain where water, etc would not normally run.

Such a method of testing is very crude and does not really tell you anything useful.

A much better basic test is simply to have two people - one at each end - and put a pre-determined numer of buckets of water down the drain and for the person at the other end to see if it comes through. It is does not or is substantially less than put down you probably have a problem.

It is up to you. You could have a CCTV test (c. £200-£300 - subject to length in question, etc), but this could reveal a whole load of horrors (more than £500), or nothing at all - but it will still have cost you. You might prefer to knock off the £500 as a quick easy solution.

 

[Nemesis]

It's rather like smoke testing chimneys.

Testing which could be destructive is an interesting one - I wonder who is liable if damage is done?

I also wonder why the nice round sum of £500 - is that an estimated cost of repair, or just something plucked from the ether?

 

[Penners]

I'm not sure that running your own tests will have any effect on the situation. The argument will then come down "my test is better than your test"!

The fundamental question is this: will your purchasers really pull out of the deal for the sake of a possibly leaking drain? It really comes down to a test of nerve - yours versus the potential purchasers'.

If I were in your place, I think I would assure the purchasers that you have never had any indications of problems with the drains (assuming this is the case), and you're not prepared to give away £500 on the basis of a questionable test.

If they crumble - well and good. If they stand fast, then you'll have to crumble if you want to hang on to the sale!

But of course the decision is yours.

 

[chuckey]

The sewer pipe from the bathroom in my victorian house, runs down the side of it ( about 40') then dives down to join the 6" sewer under my neigbours lawn (!!!). One Christmas the Loo refused to flush properly. When I rodded the sewer back towards the bathroom, I found the blockage at about 20' so I dug up the asphalt path to find some old flagstones, when these were lifted, there was the drain with a large cutout in the top of it and filled with hedge roots. This seemed to be a Victorian rodding point. What I am trying to say is that the drain would have failed a "drain" test but subject the trimming the hedge roots, has worked OK for about 100 years. Its got a screw down manhole cover on it now and is properly flaunched.