Cost recovery is a prerequisite for sustainable water service provision. For water utilities, one of the key determinants of overall cost recovery efficiency is the ability to recover payment, within a reasonable timeframe, for all the water bills sent to customers. This study used empirical data, obtained through a cross-sectional survey in eight small urban centres in Uganda, to establish the determinants of customer decisions to pay utility water bills promptly. Regression analysis on the data showed that customer attitude towards prompt payment, perceived ease or difficulty of paying on time (perceived control), as well as social pressure, strongly influence intentions to pay, which in turn directly affects actual prompt bill payment behaviour. The results also show that attitudes towards prompt payment are informed by perceptions of benefits and sacrifices associated with the behaviour, while social pressure is perceived to come from family members, neighbours and the utility itself. Perceived control was found to reflect both internal and external impediments to prompt bill payment, many of which relate to service issues that are within the control of water utility managers.