What the tenancy agreement says
Contractual duties tend to arise from the tenancy agreement that a landlord (whether they are a private or a social landlord) has with his/her tenant(s). Therefore, it is helpful to breakdown exactly what the tenancy agreement says about landlord duties in relation to repair and disrepair issues.
A tenant always occupies premises under the terms of a contract of letting. The contact may be in writing, or it may be verbal or assumed from the actions of the landlord and the tenant. In other words, one person occupies premises and the other accepts rent from them. The terms of the tenancy agreement relating to disrepair may either be in express terms, in the contract following agreement between the landlord and tenant either orally or in writing, and/or in implied terms, which are to be read into the contract as a result of statute or common law. For more information on leases, please see the section on the essentials of leases.
To determine which statutory duties apply to the landlord you'll need to know the security of tenure. Scottish secure tenancies  are subject to the landlord's repairing obligations are outlined in the Housing (Scotland) Act 2001.  Private tenancies  are subject to the repairing standard found in the Housing (Scotland) Act 2006.  Whatever the lease actually says (and many leases are likely to be silent on the matter) it is important to remember that while the landlord may try to evade her/his liability to repair, s/he can only do so in specific circumstances . Even if the landlord manages to exclude her/his common law duties, s/he cannot exclude her/his statutory duties. Another point to consider is that in any court action because of disrepair, if the landlord has tried to exclude or modify her/his obligations, and if there is any ambiguity in the repair clause of the tenancy, then that clause will be looked at by the court in favour of the tenant. There is also a legal presumption that there is no intention to contract out of the common law. 
Like the landlord, the tenant has repairing responsibilities that are found in the express and implied terms of the tenancy.
The tenant is under an implied duty to use the subjects with reasonable care. This means that any damage caused by the tenant's negligence in this duty will have to be made good by her/him. The duty would include such things as turning off the water if going away in winter.  The duty does not cover fair 'wear and tear', as these are the landlord's responsibility.
Last updated: 10 February 2020
s.11(1)(b) and sch.4 Housing (Scotland) Act 2001
sch.4 Housing (Scotland) Act 2001
s.12 Housing (Scotland) Act 2006
chpt.4 Housing (Scotland) Act 2006
secure tenancies: s.24 & 26 Housing (Scotland) 2001, private tenancies: s.17 Housing (Scotland) 2006
Hastie v Edinburgh District Council 1981 SLT (Sh. Ct.) 61 and 92
Mickel v M'Coard 1913 SC 896 1913 1 SLT 463 where a tenant leaving a house empty in winter without turning off the water or telling the landlord was held liable for the damage caused by burst pipes