Washing machine into Gully Trap ?

8 Feb 2021
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United Kingdom
hi there,

My kitchen sink , washing machine and dish washer all exit the house into a drain pipe and into the sewer run.

Ive had some problems with a collapsed drain on a different part of the run ,,,,, but while im there I want to look at installing a gully trap that rain water/washing machine etc fall into .
There was no gully trap before ( cast iron so quite old etc. , and i have a slight suspicion sewer gas smells come form the set up. Even though the three run to the U trap under the sink.

is sthere any downsides for the outlet ( washin mach/dishW/sink / to run directly into a https://www.toolstation.com/universal-gulley-trap-110mm/p82113 this universal gully trap and then onto sewer .... as apposed to straight to sewer as it does now?

Note - its not into a shore and then into gully - I mean directly into it underground.
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Trap under sink is faulty or the smell comes from somewhere else.
Would advise against the gulley trap.
Any pics from under sink?
Thanks Schrayder, pic attached
( reputable plumber did the attachments before I got interested in diy)

Really interested to know why no gully underground , presume it risks a back up to machine etc ?


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Does the waste currently exit through the wall and join into the sewer externally? Nothing wrong with fitting a Gully externally if you want to, but go for the Bottle type Gully rather than a Hopper and the 'Tick trap' you've pictured. (Bottle gullies are easier to clean out.)

Only other point of note, those drain hose, need to come up as high as possible under the sink before dropping down to the discharge connection. Risk currently of discharge from the sink backflowing into the appliances.
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thanks for tip re hoses, I take it you mean they need to be clipped higher and not free hanging . makes sense.

re the exit - yes straight out , into cast iron down pipe and into sewer. ( all enclosed)

If i was having a gully it would also be enclosed ( not cleanable except with a rod if i created rodding point on the steel i suppose ...
( does that make sense ? the only reason I want a trap is an extra barrier against possible sewer gas but im probably not making sense
What you currently have is to an acceptable standard, direct connection to a stack or drain is perfectly normal practice, provided the Trap has a 76mm depth of seal. A gully may even cause more issues than it solves, it'll need to be connected to the drain run, (not the stack), may involve a lot of digging if the drain is deep, (with associated risk of damaging anything else in the vicinity, e.g. water, gas, electric supplies), and Gullies can get a bit whiffy in the warmer months.

I think to be honest, you may well be looking for problems that aren't there currently. Old adage, 'If it works, dont fix it.'
As above looks ok in there.
Running waste into a gulley traps dirty water in the trap of the gulley which can then smell, esp in summer.
Imo get your nose in there and see where the smell is coming from, find cause of problem then find soution.

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