This report summarizes the current state of knowledge on the persistence of biological agents on drinking water infrastructure (such as pipes) along with information on decontamination should persistence occur. Decontamination options for drinking water infrastructure have been explored for some biological agents, but data gaps remain. Data on bacterial spore persistence on common water infrastructure materials such as iron and cement-mortar lined iron show that spores can be persistent for weeks after contamination. Decontamination data show that common disinfectants such as free chlorine have limited effectiveness. Decontamination results with germinant and alternate disinfectants such as chlorine dioxide are more promising. Persistence and decontamination data were collected on vegetative bacteria, such as coliforms, Legionella and Salmonella. Vegetative bacteria are less persistent than spores and more susceptible to disinfection, but the surfaces and water quality conditions in many studies were only marginally related to drinking water systems. However, results of real-world case studies on accidental contamination of water systems with E. coli and Salmonella contamination show that flushing and chlorination can help return a water system to service. Some viral persistence data were found, but decontamination data were lacking. Future research suggestions focus on expanding the available biological persistence data to other common infrastructure materials. Further exploration of non-traditional drinking water disinfectants is recommended for future studies.

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This report summarizes the current state of knowledge on the persistence of radiological agents on drinking water infrastructure (such as pipes) along with information on decontamination should persistence occur. Decontamination options for drinking water infrastructure have been explored for some important radiological agents (cesium, strontium and cobalt), but important data gaps remain. Although some targeted experiments have been published on cesium, strontium and cobalt persistence on drinking water infrastructure, most of the data comes from nuclear clean-up sites. Furthermore, the studies focused on drinking water systems use non-radioactive surrogates. Non-radioactive cobalt was shown to be persistent on iron due to oxidation with free chlorine in drinking water and precipitation on the iron surface. Decontamination with acidification was an effective removal method. Strontium persistence on iron was transient in tap water, but adherence to cement-mortar has been demonstrated and should be further explored. Cesium persistence on iron water infrastructure was observed when flow was stagnant, but not with water flow present. Future research suggestions focus on expanding the available cesium, strontium and cobalt persistence data to other common infrastructure materials, specifically cement-mortar. Further exploration chelating agents and low pH treatment is recommended for future decontamination studies.

This article discusses effective crisis communication as a key responsibility of water utility officials and public information officers during emergencies. Mental noise theory, a primary construct of risk communication, is discussed in the article and indicates that when people are extremely upset, they often have difficulty hearing, understanding, and remembering information. The challenge for risk communicators is developing a limited number of key messages that are brief, credible, and easily understood. The article presents a powerful tool available to water sector crisis communicators for identifying and developing key messages called message mapping. The article discusses several principles that come into play when developing messages for high‐stress situations. A sidebar is included in the article presenting the three key points of message mapping.

Past use of weaponized Bacillus anthracis spores has prompted increased interest in studying the inactivation of potential bacterial bioterrorism agents in drinking water. Conditions for chemically inactivating many regulated waterborne disease‐causing species are well known, but there are only limited data available on inactivating microorganisms that could potentially be used as biological weapons. Information on the likelihood of such agents surviving in drinking water containing disinfectants is needed to ensure that end users are sufficiently protected.