Community development projects almost universally require communities to contribute collectively towards project costs in cash, materials, or labor. But despite their ubiquity, we know little with certainty about the consequences of such collective contribution requirements or whether these consequences differ when contribution requirements are in cash or labor. We experimentally evaluate the effects of community contribution requirements in cash and in labor in a project to provide safe sources of drinking water in rural Bangladesh. Cash contribution requirements lead to a large decline in take-up and impact, relative to a contribution waiver, while labor contribution requirements with the same value when priced at the market wage do not. The difference appears to arise because many households value their time below the market wage. Substantial welfare gains may be realized by replacing cash contribution requirements with labor contribution requirements in other contexts in which the monetary value of time is low.