The phenomenon of uplink/downlink (UL/DL) link imbalance in 3G High Speed Packet Access (HSPA+) Heterogeneous Networks (HetNet) presents one of the main challenges in HetNet deployments. In this paper we describe the impact of the imbalance on system behaviour and quantify the amount of affected user equipments (UEs) in the Strong Imbalance Zone (SIZ).