Best (or diy) foamy drain cleaner

Just use hot water and bleach several times

There are thickened formulations of bleach which do cling to biofilm for long enough to see it off. That and the odd kettle of hot water every now and then ought to see it off.

It might be worth figuring out what it is you are putting down the sink drain that provides food for the smelly bacteria to live on.

It will still take the path of least reassurance and miss parts of the drain.

Food waste? Washing things with food leftovers on them is what kitchen sinks are for. Hardly a mystery what might be feeding the bugs down there.

Tim

From past experience I suggest looking at where the dishwasher outlet connects, and also to make sure that you have the recommended "inverted U" air trap in the dishwasher hose. The other source is usually the horizontal section of pipe between the two sinks. Make sure it slopes appropriately. I ended-up having a separate trap for each bowl and joined the outputs.

If its an open outlet pipe just stuff a plastic carrier bag up it. It will probably need to drip in order to completely fill the pipe.

Washing soda and hot (boiling) water.

It the same to clean washing machines and get rid of any smell - washing soda crystals and the hottest cycle wash.

Put a bung into the next manhole cover downstream then fill up with a nice mixture of Lidl bio washing detergent and bleach until it backs then leave for as long as you can and then remove the bung. Fill up upstream of the bung, of course.

Wear eye protection when you remove the bung and keep your mouth shut :-)

There are special expanding bungs, like doughnuts with a plastic thread in the centre to make it seal. Screwfix sell one for about £12 but they can be cheaper elsewhere.

Hence the 200 mtre fatberg down in devon, and regularly in parts of London.

How will the new 'super sewer' be cleared of fatbergs ?. Will they keep a TBM in a siding just in case ?.

Jethro_uk expressed precisely :

I find that no cleaner works well, or for long - the problem is that the cleaners and bleaches just run off the parts in the drains where the smells are caused. To work, the water/fluid level needs to be held higher.

What I found to be effective with minimum dismantling, is to simply block the outlet, then add bleach and water in the sink, so it is full to the plug hole level and leave it over night. Next morning it will all be spotless and smell free.

In my case I made a short bit of the plastic bit with a bung at the end, so I could simply disconnect and bung up the final leg of the pipe to seal it, to do the deed.

On 09/10/2019 14:27, Andrew wrote: ... snipped

Not when you use a dishwasher. I knock big stuff like chop bones off into the rubbish bin and put the plates etc into the dishwasher. When the dishwasher is putting what food scraps are left into the drain its doing that with the stinking hot very alkaline wash water so you don?t get a problem with any food scraps on the plastic waste pipes above the U bend under the sink.

I googled for a way to clear the film in the overflow pipe, and found: canned shaving cream. Needs a bit of tubing to get it where it needs to be. It stays in place well; leave in overnight at least.

I found it works, slowly and needs to be reapplied a few times -- but it works cheaply and easily (once the tubing stays on the nozzle).

Thomas Prufer