Single Room Rent Restrictions (SR3) is a policy in the United Kingdom that governs the maximum rent that can be charged for a single room in a shared house. The purpose of SR3 is to protect people who rent out single rooms in shared accommodation by ensuring that they are not charged excessively high rents which are unaffordable. SR3 applies to landlords renting out a single room in a shared house, but not to bedsits, self-contained flats or houses, or rooms in halls of residence. The maximum rent that can be charged for a single room in a shared house is typically based on the local housing allowance rate for the area, and the number of people sharing the house. SR3 also applies to landlords who are renting out single rooms with shared facilities.