My wife and I live in one of two semi-detached units.
Recently, when our neighbours flush the toilet, the refilling of the cistern produces a load noise of rushing water. The noise is so load that we have to crank up the volume of our TV for the two minutes or so it takes to refill the cistern!
Our neighbours assure us that they have not made any changes to their plumbing.
Any ideas/suggestions as to what causes the noise and how to eliminate it?
Has your city pressure increased? The person next door may have an obstruction in the angle stop or fill valve that is causing the water to be restricted slightly. Other than telling them to use the toilet only when your gone you may have to get your landlord involved. Good luck I feel your pain