Smelly kitchen sink drain

[JohnD]

have you cleaned the overflows?

What cleaner do you use to remove greasy dirt?

Does anyone pour cooking fat or oil down the sink?

 

[Harry Bloomfield]

If that was for me - no grease or oil goes down at all, just veg washing and washing up - we use Fairy for washing up and bleach to try to deal with the smell.

 

[dogfonos]

If that was for me - no grease or oil goes down at all, just veg washing and washing up - we use Fairy for washing up and bleach to try to deal with the smell.

Likewise, although I use caustic soda solution to remove grease before using bleach. Thick bleach usually contains caustic soda so that could be a "one-stop" solution. Thin bleach won't remove the grease etc that harbours the smells hence the short-lived success.

I've altered the plumbing on one sink bowl so the bowl drains directly into a P trap. There's now only 4" of vertical drain pipework between steel bowl and water level in the trap instead of around 2 feet of mixed horizontal and vertical pipework. Should make cleaning far more successful. Second bowl pipework to be altered later today.

Yesterday, a local plumbing shop offered me a bottle of 98% sulphuric acid as an excellent drain cleaning agent. Yikes! It is, but having worked in the chemical industry for decades, I wouldn't have it in the house. Caustic soda is nasty enough but you really need to know what you're doing with 98% sulphuric acid.

I have a similar smelly sink problem, with a P trap directly below a 1 plus 1/3 kitchen sink

Do you have a P trap on each bowl or do both bowls share one? If you have a P trap located directly below each bowl, there's a good chance that cleaning agent poured around each bowl's drain will contact all internal pipework surfaces down to the water in the trap thus making cleaning more successful. I wouldn't expect your kitchen sink smells to be originating from downstream of the P trap - assuming the trap remains full of water.

My problem seemed to be that there was far too much pipework between each bowl's drain and the U-bend, much of it horizontal, making it difficult to contact all pipework surfaces with cleaning agents. I cleaned out a good few mm's of sludge when I disassembled the pipework - just as I did earlier this year. Incidentally, a Mcalpine diagram I saw today showed a pipework manifold arrangement almost identical to the one I had (see photo in post#6) so my plumbers were working to a Mcalpine recommended configuration (though not a sensible arrangement in my opinion).

 

[Harry Bloomfield]

Both bowls share the same trap, with the trap directly below the main bowl. The pipework includes a third option to connect maybe a dishwasher drain, but that is blanked off. I think it needs a rule of not putting anything down the small sink drain, to help prevent the smells - usually when washing up, dirty dishes are sometimes rinsed off first in the small bowl.

 

[Newboy]

local plumbing shop offered me a bottle of 98% sulphuric acid as an excellent drain cleaning agent

Anybody suggesting using this type of product on above surface/internal/plastic pipework needs to be slapped repeatedly until they understand the stupidity of the suggestion. It still amazes me that acid of this strength can be bought by anybody and used with little understanding of the potential danger.

 

[dogfonos]

I think it needs a rule of not putting anything down the small sink drain, to help prevent the smells

That is inconvenient though. Why not add another P trap directly beneath the second bowl?

It still amazes me that acid of this strength can be bought by anybody and used with little understanding of the potential danger.

Absolutely. Should not be generally available.

Right, that's both my kitchen sink bowls fitted with P traps. Only 4" of vertical pipe between each plug hole and the water in the P trap beneath so should be simple to clean but I'll give it 3 months before drawing any conclusions. If I remember, I'll update this thread for reference. Thanks to all for your help and guidance.

 

[Newboy]

Just a quick check, earlier in the thread there were recommendations that the dishwasher waste pipe be raised up - have you done this as well as modifying the waste/traps?

If the water from the sink backflows into the dishwasher it may not show up inside the dishwasher but when the dishwasher starts it's cycle and pumps out any water in the sump it results in fetid water being pumping into the sink waste and can produce a quite impressive stench.

 

[dilalio]

It still amazes me that acid of this strength can be bought by anybody and used with little understanding of the potential danger.

It can't (or shouldn't be) seen my local shop refuse sale of 1shot to several disgruntled customers... There are 'other' outlets in the locale who are not so scrupulous!

 

[dilalio]

 

[Newboy]

Well that's good news - ta for the info

 

[dogfonos]

Just a quick check, earlier in the thread there were recommendations that the dishwasher waste pipe be raised up - have you done this as well as modifying the waste/traps?

Ah, forgot to mention that. Yes, the dishwasher waste pipe has been fixed as high up as possible within the under-sink cupboard. Thanks.

 

[Newboy]

 

[dogfonos]

Right, that's both my kitchen sink bowls fitted with P traps. Only 4" of vertical pipe between each plug hole and the water in the P trap beneath so should be simple to clean but I'll give it 3 months before drawing any conclusions. If I remember, I'll update this thread for reference. Thanks to all for your help and guidance.

For the sake of completeness...
I know it's only two months since the drainage plumbing mods - but two hot months and there's no smell whatsoever from the sink drains. Haven't even needed to use any cleaning agents. Sorted.

 

[Harry Bloomfield]

..and no smells from my sink either, since I blocked the outlet pipe, to enable the entire system to have a good submerged soak in bleach over night.