Nasty subject about sewer blockages

Kashkai

I have ongoing issues with the sewers around my house getting blocked by loo paper that is practically waterproof as it won't break down and clogs the AJ where three pipes meet and then backs up the toilets. I've used different brands of loo roll but no joy. Last Saturday was especially bad and it took 30 minutes of scooping this loo roll out of the sewers and flushing the pipes to clear them.

Anyone got a suggestion to stop this happening. It's not the angle of the sewers as once the blockage is cleared, the wastewster flows freely to the septic tank.

Martron

it actually could be the angle of the sewers.

if the fall is too great what happens is the water flows faster than the paper and waste and basically leaves it behind.

also what could happen at an aj if there is a 90 degree bend or even if the aj is install incorrectly and the waste enters the aj against the flow it could just depeosit the waste and paper in the aj and the water rushes off.

BostonB

Can't be the paper. Must be something else. is this a new sewer?

whacker4fun

Could be the type of pipe used. There is a roughness co-effecient for all pipes which basically means the smoothness of the inside lining of the pipe.
Seems as if it is the gradient/slope/angle of the pipework.
who built the drainage? Get a builder/engineer to check it on site!

Kashkai

Sewers were laid by my builder who was a boll0x of the highest order but in this instance, I don't think I can blame him for this one.

To give a better idea, the pipe leading off to the septic tank comes out at the 3 o'clock position. The pipes leading in are at the 11, 9, and 7 o'clock positions so no sharp angles there. When I dug the loo paper out with a small shovel, it stayed intact when in my opinion, it should have broken up after being immersed in wastewater for a week. Once this was removed, the sewers emptied themselves into the septic tank. I flushed all the loos to clear any residue until they ran clear. However I'm sure thus will happen again.

The pipes are standard 100mm wavin soil pipes.

looksee

We have the same problem, the pipes have to be flushed about every year at some stage. The buildup is the same as yours, but we are on mains drains. I have used a (small, cheap) pressure washer and jetted the far side of the blockage so that a space is cleared for the blockage to start moving, rather than trying to force if from behind the blockage. With a bit of patience, and standing well back as you do it I have found it clears it fine.

slavetothegrind

I suspect matron is right!

you should have aj's at 20 ft intervals or so to your tank, if you pour a half bucket of water in one and go to the other is it flowing strongly or gently?
Should be slow and steady rather than pissing along ( sorry:o)

Dave you are surely due a lotto win as karmic compensation for the gaff!

Use two sticks with equal graduations in centimetres and a water level to determine the fall between aj's

Martron

i have seen it before.

an easy way would be to load your bowl up with toilet paper and flush. ( well get someone to do it and you watch at the aj where the blockage is.

if the majority of water flies by without the paper it could be the gradient.

i deally ( when i was installing house connections) the fall should have been 1 metre for every 100m but no more that 1 m for every 60m .

if you can get the height difference between the last known pipe and your aj and divide it by the distance will give you fall per metre.

then dvide 1 by this number and it will give you your overal fall per metres.

antiskeptic

Prosperous Dave wrote: »

I have ongoing issues with the sewers around my house getting blocked by loo paper that is practically waterproof as it won't break down and clogs the AJ where three pipes meet and then backs up the toilets. I've used different brands of loo roll but no joy. Last Saturday was especially bad and it took 30 minutes of scooping this loo roll out of the sewers and flushing the pipes to clear them.

Anyone got a suggestion to stop this happening. It's not the angle of the sewers as once the blockage is cleared, the wastewster flows freely to the septic tank.

It's unlikely to be the loo roll. When wet loo roll is a sodden mass compacted together then it's not going to fall asunder.

One workaround to try is to simply increase the quantity of water in the cistern(s) by adjusting the shut position of the ballcock - giving each flush a better shot at carrying the waste along.

Kashkai

antiskeptic wrote: »

It's unlikely to be the loo roll. When wet loo roll is a sodden mass compacted together then it's not going to fall asunder.

One workaround to try is to simply increase the quantity of water in the cistern(s) by adjusting the shut position of the ballcock - giving each flush a better shot at carrying the waste along.

You might have something there as I've found that one of the loos emptying into this AJ has a poor flush (I think the syphon is broke in the cistern) and my two daughtes have now admitted to using lots if loo roll. So lots of loo roll and poor water flow might be the cause. I'll ban them from using thus loo to see if the problem goes away and if so I'll then have to get round to fixing the broken syphon.

Btw I checked the fall of the sewer and it was a gentle slope from AJ to AJ.

Thanks for the advice lads.