Going down the Drain?

When carrying out the end of tenancy inspection on a student let, I encountered a completely blocked drain outlet from the kitchen and bathroom. This was so bad that the adjacent paved area of the yard had been flooded which had left a congealed mat of fat and there was a watermark and crud on the wall and pipework.

I have always encouraged my student tenants to report any minor defect before it develops into a crisis, so this was a shock. Now that the property is unoccupied, it seems certain that the problem is serious, as the residual water has not drained away.

As we are between tenancies I need to get the drain cleared, however, the departing tenants deny that it is their responsibility and I cannot reach an agreement with them regarding retaining the drainage contractor’s costs from their deposit.

Apart from this problem, the tenants have left the property clean and I will be returning the balance of their deposit in full.

Has anyone had a similar experience and perhaps taken the issue to arbitration by Mydeposits. Surely this sort of neglect does not fall into the normal wear and tear category?

Best wishes
Johnonothing