Deciding who is responsible for cleaning mould depends on how it appeared in the first place. The tenant should notify the property manager/owner as soon as they are aware of a mould issue.
Generally, if the mould is a result of problems with the property (e.g. a leaking roof, or water damage found around a bathroom from leaking pipework) it is the property manager/owner’s responsibility to clean the mould and make any necessary repairs.
Some buildings may be more prone to mould due to factors such as the age of the building, structural issues, location, or the absence of adequate ventilation or extractor fans. The property manager/owner is more likely to be responsible for mould in these circumstances.
If the tenant causes the mould they are responsible for cleaning it and paying for any damage caused.
Example: if the tenant continually allows steam to build up in the bathroom without proper ventilation and/or regular cleaning, resulting in mould, they may be responsible for the mould.
Any specific arrangements about mould should be included in the special terms of the agreement.