Many tenants of a house or flat have other people living in the premises, often with no express agreement between them as to the terms on which the others remain, except for the amount of their contributions to rent and other expenses. Whether they are joint tenants, sub-tenants or merely boarders or lodgers of the tenant depends on the circumstances.

If two or more tenants enter into a tenancy agreement together they are joint tenants and are jointly and severally (separately) liable for the obligations of the tenancy. This means that any one of them can be liable for the full amount of the rent and the full cost of any compensation payable to the landlord in respect of a breach of the agreement. The landlord can bring an action against one or all of the tenants. Where liability is joint and several, the fact that one person has not caused the loss is not a defence. Where disputes arise between joint tenants the Residential Tenancies Act 1995 does not apply and the tribunal has no jurisdiction. Disputes such as payment of expenses or the repayment of bond money must be sorted out between the co-tenants and if necessary can be resolved using mediation or alternatively in the Magistrates Court. If a bond is lodged in several names, the Tribunal will generally pay it out in equal portions.