Shared drain

[dormermike]

Hi

Neighbours inspection chamber drains into one at the bottom of my driveway which then enters sewer in road. They are having block paving installed and uncovered a inspection chamber which was blocked.

Drain company jetted their inspection chamber and the toilet trap on my side was gurgling and the shower trap actually sprayed out water.

Does this indicate a blockage on my side? I am unable to lift the chamber because it is inset with bricks and too heavy.

Drain jet guy couldn't care less and "guaranteed" it couldn't possibly be anything to do with their activities.

Thanks
Mike

 

[bernardgreen]

The blockage in the pipe under your drive that serves you AND your neighbour is not your responsibility. The local water company are responsible as it is a shared pipe serving more than one property.

http://www.dwrcymru.com/en/My-Wastewater/My-Responsibilities.aspx

 

[Hugh Jaleak]

I can virtually guarantee you it was to do with the jetting! I work for a Water Company, part of my job is driving/operating a 'Combination' unit, which is a vacuum tanker and jetting unit combined, hence the name. We have completed training on 'Blowback Avoidance', (which is what you've just had!), and have check lists and procedures to follow prior to starting any jetting work.

Basically, the jetting head, which is spraying water out at high pressure, (our unit can bang water out at 200 bar/2900psi at a gallon a second, smaller units wont be quite as powerful), and the action of the jets actually fills the pipe, thus pushing the air in the pipe ahead of the jet forward. If this pressure cannot escape naturally via a vent it'll take the next easiest path, usually through a WC.... In your case it couldn't escape any other way, and the heavy cover prevented any possible escape of air from there, so it came out via shower and WC! You, (and the drainage company) were lucky! High pressure water has to be treated with respect, and is dangerous in the wrong or untrained hands.

Despite taking all the precautions, (lifting manhole covers along the run, reducing pressure, etc), we have still managed to blow toilets, and believe me, the result isn't pleasant. This is part of the reason I don't like people removing vents and replacing with AAV's, ("as it looks neater"). Removing an open path for positive pressure to escape is asking for trouble, we then come along and jet the line, and result is an unholy mess in their new bathroom....

 

[dormermike]

Thanks. I knew it was to do with the jetting, there is nothing else it could have been. I nearly blew my stack with them. Not just the incompetence but the gall to suggest, no "guarantee" that it was not them. My concern is if they come back when I'm not here.

All they've done is shove the problem further down the line!

 

[dormermike]

I can virtually guarantee you it was to do with the jetting! I work for a Water Company, part of my job is driving/operating a 'Combination' unit, which is a vacuum tanker and jetting unit combined, hence the name. We have completed training on 'Blowback Avoidance', (which is what you've just had!), and have check lists and procedures to follow prior to starting any jetting work.

Basically, the jetting head, which is spraying water out at high pressure, (our unit can bang water out at 200 bar/2900psi at a gallon a second, smaller units wont be quite as powerful), and the action of the jets actually fills the pipe, thus pushing the air in the pipe ahead of the jet forward. If this pressure cannot escape naturally via a vent it'll take the next easiest path, usually through a WC.... In your case it couldn't escape any other way, and the heavy cover prevented any possible escape of air from there, so it came out via shower and WC! You, (and the drainage company) were lucky! High pressure water has to be treated with respect, and is dangerous in the wrong or untrained hands.

Despite taking all the precautions, (lifting manhole covers along the run, reducing pressure, etc), we have still managed to blow toilets, and believe me, the result isn't pleasant. This is part of the reason I don't like people removing vents and replacing with AAV's, ("as it looks neater"). Removing an open path for positive pressure to escape is asking for trouble, we then come along and jet the line, and result is an unholy mess in their new bathroom....

And thanks very much for the detailed explanation. I've written to neighbour letting them know what happened and asked them not to let the drainage company back as we are all very lucky! not what you'd need right before Christmas. .. or anytime really

 

[Hugh Jaleak]

Thanks. I knew it was to do with the jetting, there is nothing else it could have been. I nearly blew my stack with them. Not just the incompetence but the gall to suggest, no "guarantee" that it was not them. My concern is if they come back when I'm not here.

All they've done is shove the problem further down the line!

With luck they've shoved it into the road, but I would be hoping the jetter has broken up whatever was down there, assuming it was a 'soft' blockage, which should have washed away and not a lump of brick/concrete/rimblock/bunch of wipes....

If the drain is shared, then it's the Water Company's (as sewerage provider) job to deal with it anyway. I would also be writing to the drainage company, and put them on notice, that if they return, and any damage occurs in or on your property, you will be holding them fully liable.

We often get people coming out saying their toilet is bubbling or gurgling, and is it anything to do with us? Short answer is yes, and although we carry out all necessary checks and take the required precautions, you cannot totally remove the risk. Buried manholes and removal of open vents in favour of AAV's don't help. We've even been told by the Tutor who takes our jetting courses, (a highly experience individual who has spent many years in the industry, was a founding member of a large water jetting company and the Water Jetting Association), that even with taking all precautions, blowbacks can never be totally eliminated. In the worst case scenario, it's what your public liability insurance is for.

 

[HERTS P&D]

The splash back in your property was due to them having the jetter hose too far up your drain line.

I have done it a few times.


To confirm your drain line is clear is easy, just leave your bath tap running.

Andy

 

[dormermike]

OK thanks everyone

I probably panicked a bit but the chap claiming it couldn't possibly be related to the jetting got my heckles up a bit.

 

[Hugh Jaleak]

No damage done, but the possibility was there. The jetting guy also perhaps needs to stop being so blasé and think before firing the jet up pipes without a thought to consequences. I had to do a 3 day course before they'd let me loose on our machine, (and then I was with a trained operator).