So when you tip the dishwasher backwards and drains the water out i take it the dishwasher is working for a bit till it stops with water in the base again, Is this correct?
If so then you have something leaking under there thats causing this fault.
What you need to do is remove the top (if free standing) and then remove both side panels.
From there you will be able to see the workings under there.
Shine a tourch under there and check for loose hoses.
If the hoses are fine then you need to start the dishwasher going carefully with the panels off and watch it as it washes.
As from there you should be able to see where the leak is comming from.
Check these are they are the most common things to leak on these.
Look at the right hand side and there you will see the wash motor. Check this when its washing and see if water is leaking from there as they are prone for leaking as the seal kit wears and leaks.
If thats fine then check the filling tank on the left hand side and see if you can see whater leaking from there as well.
So check them and see what you find and hopefully you can find the cause of the leak from there.
If you need anymore info just get back to me.