Household water treatment can reduce diarrheal morbidity and mortality in developing countries, but adoption remains low and supply is often unreliable. To test effects of marketing strategies on consumers and suppliers, we randomized 1,798 households in rural Haiti and collected data on purchases of a household chlorination product for 4 months. Households received randomly selected prices ($0.11-$0.56 per chlorine bottle), and half received monthly visits from sales agents. Each $0.22 drop in price increased purchases by 0.10 bottles per household per month ( < 0.001). At the mean price, each 1% drop in price increased purchases by 0.45% (elasticity = 0.45). There is suggestive evidence that household visits by some sales agents increased purchases at mid-range prices; however, the additional revenue did not offset visit cost. Choosing the lowest price and conducting visits maximizes chlorine purchase, whereas slightly raising the retail price and not conducting visits maximizes cost recovery. For the equivalent cost, price discounts increase purchases 4.2 times as much as adding visits at the current retail price. In this context, price subsidies may be a more cost-effective use of resources than household visits, though all marketing strategies tested offer cost-effective ways to achieve incremental health impact. Decisions about pricing and promotion for health products in developing countries affect health impact, cost recovery, and cost-effectiveness, and tradeoffs between these goals should be made explicit in program design.

Despite documented health benefits of household water treatment and storage (HWTS), achieving sustained use remains challenging. In prior evaluations of a long-term HWTS program in Haiti, multiple marketing interventions failed to increase use or had prohibitively high costs. Using mobile phones is a potentially cost-effective way to change HWTS behavior. We conducted a randomized experiment to evaluate the impact of sending short-message service (SMS) messages to promote household chlorination in this program in Haiti. Households (n = 1327) were randomly assigned to: One of four SMS frequencies; one of ten behavioral constructs; “cholera” or “disease” framing; and one or zero household visits from a sales agent. During the three-month campaign, there were no statistically significant relationships between the four outcomes related to chlorine purchases and any SMS frequency, any behavioral construct, or either “cholera” or “disease” framing. Receiving one visit increased the probability of purchasing a bottle of chlorine by 17.1 percentage points (p < 0.001) but did not affect subsequent purchase behavior. Costs of managing the SMS campaign were higher than expected. SMS campaigns may not be cost-effective behavior change interventions in certain contexts. If pursued, we recommend simple interventions, timed with the target behavior, and tailored to mobile phone usage patterns of the target population.