What are the benefits of moving from intermittent water delivery (which limits user access to less than 24 h per day) to constant service? To address this question, we study the transition from intermittent to constant water supply in London. Between 1871 and 1910, the proportion of London households with access to a constant water supply (24 h a day, 7 days a week) rose from less than 20–100 percent. Idiosyncratic delays in the negotiation process between companies and property owners generated random variation in the timing of the transition across London districts. Exploiting this variation, we find that a one percentage point increase in a local population with access to constant service decreased deaths from waterborne diseases by as much as 0.4 percent and explains approximately a fifth of the late nineteenth century decline in waterborne disease mortality. Results are robust to the inclusion of controls for population density, concerns regarding the reporting of cause-of-death, district-specific time trends, district demographics and spatial autocorrelation.

从间歇供水（将用户每天使用时间限制在 24 小时以内）转变为持续供水有什么好处？为了解决这个问题，我们研究了伦敦从间歇供水到持续供水的转变。从 1871 年到 1910 年，能够获得持续供水（每天 24 公顷，每周 7 天）的伦敦家庭比例从不到 20% 上升到 100%。公司和业主之间谈判过程中的特殊延迟导致伦敦各区过渡时间的随机变化。利用这种变化，我们发现，获得持续服务的当地人口每增加 1 个百分点，水传播疾病的死亡人数就会减少多达 0。4% 并解释了 19 世纪后期水传播疾病死亡率下降的大约五分之一。结果对于纳入人口密度控制、对死因报告的担忧、地区特定时间趋势、地区人口统计和空间自相关性是稳健的。