People choose to live in risky landscapes for a variety of reasons: they derive benefits from those places despite the risk. From a planning perspective, how much protection is it reasonable to provide these populations against the risk of death due to coastal flooding? The acceptability of risk due to natural hazard, and the levels of protection that infrastructure should provide, may be approached from several directions: from economic calculations on the value of a statistical life saved, from people's willingness-to-pay to reduce risk, from stated preferences, and from other risks that people willingly accept. This paper focuses on societal risks deemed tolerable from the last consideration, as now widely used for dam safety guidelines. Recent recommendations have been made that coastal defenses should be designed to provide the exceptionally low levels of societal risk associated with modern, well-engineered dams. These seem unreasonable. For fatalities fewer than the low thousands, the tolerable level of risk for coastal protection—based on other risks society accepts—is arguably on the order of 10⁻³ per year. This implies a corresponding acceptable level perhaps two orders of magnitude lower, to be consistent with current practice in other sectors of civil infrastructure. Between these bounds, as-low-as-reasonably-practicable (ALARP) practices seem a reasonable precaution.