What the guarantor is legally responsible or ‘liable’ for depends on what it is written in the guarantee. 
Usually the guarantee will say that the guarantor is responsible for paying the rent if the tenant(s) cannot or do not for whatever reason. The guarantee may also say the guarantor must pay for any repairs if the tenant(s) damage the property or costs such as cleaning service costs.
The terms of the guarantee may be written down in a separate agreement or included in a section of the tenancy agreement itself. Sometimes there may just be a short section, called a ‘clause’, in the tenancy agreement with a separate form for you to fill in giving your personal and bank details.
Before you sign anything make sure you read the guarantee and the tenancy agreement carefully. You need to know and understand what both these documents commit you to, before you sign the guarantee.
If there is only very limited or no information about what you are responsible for, you should ask the landlord or their agent to provide you with more, before signing anything.
Joint tenancies
When someone shares a property with other tenants under one tenancy agreement (a joint tenancy), the tenancy agreement usually requires each person to promise to pay all the rent, not just their own share. So, a tenant is responsible for paying their own rent but can also be asked by the landlord to pay all of the rent if any of the other tenants fail to pay. The law calls this being ‘jointly and severally liable’. In this situation, as a guarantor, you are likely to be responsible for whatever any of the joint tenants owe the landlord, not just what the tenant you are helping may owe.
You may also be responsible for any damage caused by other tenants, not just the one you’re wanting to help. This may not be what you expected and why it’s important that you understand the terms of the guarantee before you agree to them.
I want to be able to help out my son and his mate by acting as their guarantor but I do have some worries about it too. I would like to know if I have a right to be told that they are keeping up with their rent each month. If something changes that I don’t know about, for example if my son’s mate moves out, will that end my responsibilities?
You don’t have a legal right to be kept informed but you could suggest that your son and his friend do this and that you will only agree to be a guarantor if they commit to keeping you informed. If something changes at the property and you are not told, this might end your responsibilities. If it is a joint tenancy then usually you will be responsible for guaranteeing both tenants, rather than just your son. Your responsibilities only end when the tenancy for both of them ends. In that time if any money is left unpaid that should be paid, the landlord can pursue you for that money, for up to six years after the end of the tenancy.
