You'll find that quality varies a fair amount. However, there is absolutely nothing in housing legislation to say that ‘student accommodation’ can or should be of a lower standard than other properties let by landlord/agents. The attitude of ‘what do you expect, it’s only a student house?’ is not acceptable. Your health and safety could be at risk if you accept substandard conditions.
For much of the accommodation in your area, the quality of what's on offer and its management will be assured through a Code of Standards operated by Unipol. These Codes are helping to drive up quality and standards in markets where they have a strong presence. For guidance on the Codes and how you can make use of them to secure assurance about the quality of your accommodation, please see the section of this website devoted to The Codes.