Bath Waste water - slow flow

Hello I have recenlty installed a new bath into an old property. The waste pipe goes through a bath U bend in 40mm pipe and then runs gradually down hill over approx 3mtrs to the oposite side of the room before dropping virtically into a main waste pipe, used by the toilet and sink. The water takes ages to run out of the bath taking about 5-10mins to empty. At first I thought the pipe was not steep enough but I can't do much about the steepness. Is a pump needed? or am I missng something i.e air trapped?

Thanks

18mm /m drop is the min required for your 40mm waste.
is the basin/toilet emptying ok. as that will prove your main stack is venting ok.

Hi

The pipe drop is about 100mm over the 3 meter length. The toilet and sink seem to be emptying fine, although the bath gurgles when the sink is emptied.

L

are these pipes connected then...seems one is pulling the waste out of the other when empting..syphonage

but i cant think that it would slow the draining of the bath..

is it a new waste pipe etc...if its the old one then from what u have described i'd bet its full of scum/hair etc....long runs under floorboards without support will bendin the middle and build up craaap and eventually the pipe id becomes smaller and smaller