Bath water bubbling up through downstairs WC

[Mych]

Ive no idea of the pipe layout as only moved into house a short while back. I emptied the bath and while it was emptying I flushed the upstairs toilet. Next thing I hear is loud bubbling downstairs and rushed to investigate only to find the downstairs toilet overflowing and water bubbling up from basin waste. This is now happening all the time any water is released upstairs. Either there is an air block or some sort of back siphoning is happening.... how do I fix?

Update... after reading some suggested similar threads... I’d like to add that when the downstairs toilet drains the water level is low... barely any left. The shower and toilet in the on suite at the other side of the house all work fine.

 

[Murdoch]

You don't say where you live but if its been very cold you might have frozen or partly frozen drains ....

 

[Mych]

You don't say where you live but if its been very cold you might have frozen or partly frozen drains ..

Murdoch... thanks live in the midlands... this happened a few day back while the weather was quite mild.

 

[sammathias]

sounds to be a backed up manhole or line too your manhole

 

[Mych]

sounds to be a backed up manhole or line too your manhole

Possible but from what I can see there is only one pipe coming from house to manhole before flowing onto septic tank. The toilet in the on suite is fine so the two systems flow into the one pipe to the manhole. This means that the blockage if any will be in the pipe that leads from the front of the house, under the building to the back.

 

[Murdoch]

So if you are up to it, buy some rods and do it yourself or get a professional in .....

We have friends with a similar problem and they are used to using their rods on a regular basis, especially when they have visitors!