The Kenyan government estimates that 500 billion KES ($5 billion USD) are needed to achieve sanitation coverage targets in urban areas by 2030. To finance these infrastructure improvements, the Ministry of Environment, Water, and Natural Resources is looking at various financing options, including private sector participation, foreign aid, and cross-subsidies. Using a double-bound dichotomous choice method coupled with qualitative interviews, this study investigated willingness to pay for a pro-poor sanitation surcharge among customers of two Kenyan water utilities. 75% of respondents were willing to pay a surcharge, with just over half willing to pay up to 100 KES ($1 USD) per month. The primary determinants of willingness to pay were trust in the water utility to manage the pro-poor surcharge, feelings of solidarity towards people living without sanitation, and satisfaction with current water services.