Waste water /drains help please

homerhotspur

We are getting signs of a blockage in the drains. When we have a shower, flush the toilet , run the sink in one bathroom( at the front of the house) the water is either draining very slowly or gurgling away under the bath etc. I've managed to get one of the drain covers up in the back garden. If we flush the toilet in the back bathroom or the downstairs wc, it comes through. The ( clean) water flushed from the upstairs toilet is however brown and very smelly. If I flush the toilet from the front bathroom or turn on the shower etc, nothing happens at all. 
There are also a couple of drain covers in the front garden which may be difficult to lift. I have tried an ear test and could not hear running water when the toilet was flushed.
My questions are , is it the normal situation that the water from  all toilets/ sinks  etc in the house should all exit through the one drain ( ie the one in the back of the house) and that the combination of nothing from the front bathroom and the brown/smelly clear water suggests that is where a major blockage may be? Or , is it normal for the front bath, toilet etc to exit the house at the front?
The soil stack pokes out of the back of the roof.
Many thanks for any help

MikeJXE

All foul water doesn’t necessarily go to the same inspection chamber 

On what floors are the back toilets/sink/bathroom on, also what floors are the front ones on 

homerhotspur

Thank you for replying.
First floor , an ensuite bathroom and a family bathroom. En-suite at front of house, family bathroom at back.
Downstairs WC
Have established that downstairs WC and back bathroom do exit via drain in back garden( although smelly brown water from upstairs family bathroom) but seeking to establish about upstairs en-suite( front of house). 

MikeJXE

Have you got close neighbours and are they having problems 

homerhotspur

Not aware of anything

MikeJXE

I was wondering if you had shared drains, if so the water board would sort out the shared section 

Is the back inspection chamber is running ok, which direction  does the exit pipe go in

If the front has a blockage you need to lift the inspection cover and check that too 

Lorian

Run a little water in the bath so you know the trap is full. Then flush the toilet and go straight to the bath, is it syphoning the water out of the bath trap?

homerhotspur

Lorian said:

Run a little water in the bath so you know the trap is full. Then flush the toilet and go straight to the bath, is it syphoning the water out of the bath trap?

Hello, thanks.
Not totally sure what you mean but , on flushing the toilet, I looked in the plug hole and there was still water visible. Were you suggesting that this water should have disappeared?

Lorian

No you don't want it disappearing, it's a quick check that indicates you are not getting vacuum in the stack. 

Lorian

Does the toilet back up when you flush it?