| #Q001 | operational | health | recommended | Risk management approach implementation | drinking water | All water utilities should implement a risk management approach, such as the source-to-tap or water safety plan approach, to ensure water safety (CCME, 2004; WHO, 2011, 2012). | | high |
| #Q002 | operational | operational | mandatory | System assessment requirements | drinking water | These approaches require a system assessment to characterize the source water, describe the treatment barriers that prevent or reduce contamination, identify the conditions that can result in contamination, and implement control measures. | When implementing a risk management approach | high |
| #Q003 | monitoring | operational | mandatory | Operational monitoring and protocols | drinking water | Operational monitoring is then established, and operational/management protocols are instituted (for example, standard operating procedures, corrective actions and incident responses). | As part of the risk management or water safety plan approach | high |
| #Q004 | monitoring | operational | mandatory | Compliance monitoring and validation protocols | drinking water | Compliance monitoring is determined and other protocols to validate the water safety plan are implemented (for example, record keeping, consumer satisfaction). | As part of the risk management or water safety plan approach | high |
| #Q005 | operational | operational | mandatory | Operator training | drinking water | Operator training is also required to ensure the effectiveness of the water safety plan at all times (Smeets et al., 2009). | | high |
| #Q006 | treatment | treatment | guidance | Control strategies for high antimony sources | drinking water | In water sources with higher than acceptable antimony concentrations a treatment option discussed in the section on treatment considerations may be implemented, or non-treatment strategies such as blending or alternative water supplies can be considered. | In water sources with higher than acceptable antimony concentrations | high |
| #Q007 | design | treatment | recommended | Antimony species identification and pilot testing | drinking water | When the option of a treatment technology is chosen, the species of antimony should be identified and pilot-scale testing is recommended to ensure the source water can be successfully treated and process design is established. | When the option of a treatment technology is chosen | high |
| #Q008 | operational | operational | mandatory | Water quality evaluation prior to source change | drinking water | Attention must be given to the water quality of a new source prior to making any changes (for instance, switching, blending and interconnecting) to an existing water supply. | Prior to making any changes to an existing water supply | high |
| #Q009 | operational | health | recommended | Control strategy minimization goal | drinking water | As it is difficult to control the accumulation and release of antimony and other contaminants of health concern in the distribution system, the control strategy should minimize the antimony concentration that enters the distribution system from the treatment plant. | | high |
| #Q010 | operational | operational | recommended | Distribution system quality management | drinking water | Generally, the distribution system should be managed such that drinking water is transported from the treatment plant to the consumer with minimum loss of quality. | | high |
| #Q011 | design | operational | mandatory | System-specific control strategy requirement | drinking water | As source waters, treatment plants and distribution systems can differ significantly, a system-specific control strategy would be necessary. | | high |
| #Q012 | monitoring | operational | recommended | Source water characterization | drinking water | Water sources should be characterized to determine if antimony is present. | | high |
| #Q013 | monitoring | operational | recommended | Source water monitoring frequency | drinking water | Monitoring of source water should be conducted yearly. | | high |
| #Q014 | monitoring | operational | guidance | Reduced monitoring for source water | drinking water | Authorities may consider reduced monitoring when it has been demonstrated that antimony is not present and/or appropriate treatment is in place. | When it has been demonstrated that antimony is not present and/or appropriate treatment is in place | high |
| #Q015 | monitoring | treatment | recommended | Treatment operational monitoring | drinking water | Where treatment is required to remove antimony, operational monitoring should be implemented to confirm whether the treatment process is functioning as required (that is, paired samples of source and treated water to confirm the efficacy of treatment). | Where treatment is required to remove antimony | high |
| #Q016 | monitoring | treatment | recommended | Adsorption operational monitoring frequency | drinking water | For example, if adsorption is used, at least quarterly monitoring should be conducted or a method to estimate BVs to breakthrough should be used to predict media replacement. | If adsorption is used | high |
| #Q017 | monitoring | health | recommended | Compliance monitoring frequency for treated water | drinking water | When treatment is in place for antimony removal, it is recommended that compliance monitoring for total antimony be conducted annually, at a minimum, to confirm the proposed MAC is not exceeded. | When treatment is in place for antimony removal | high |
| #Q018 | monitoring | operational | recommended | Compliance monitoring sample collection protocol | drinking water | Samples should be collected after treatment prior to distribution (typically at the entry point prior to the distribution system) and analyzed by an accredited laboratory. | | high |
| #Q019 | monitoring | operational | recommended | Distribution system monitoring requirement | drinking water | Consequently, monitoring should also be conducted throughout the distribution system when antimony is or was historically present in the source and/or distributed water. | When antimony is or was historically present in the source and/or distributed water | high |
| #Q020 | design | operational | recommended | Distribution system monitoring program design | drinking water | Monitoring programs should be designed on a system-specific basis to verify that control strategies are operating as intended and consider risk factors that contribute to the likelihood that antimony may be elevated within the drinking water system. | | high |
| #Q021 | monitoring | operational | guidance | Indicators for monitoring antimony release | drinking water | Factors that influence antimony accumulation and mobilization, such as changes to water chemistry and physical/hydraulic disturbances in the distribution system, could be used as indicators of when and where to monitor for antimony release. | | high |
| #Q022 | monitoring | operational | recommended | Monitoring during disruptions | drinking water | Monitoring for total antimony and other contaminants (for example, iron, manganese, arsenic, lead) should be conducted when water quality changes or physical disruptions occur in the system. | When water quality changes or physical disruptions occur in the system | high |
| #Q023 | monitoring | operational | recommended | Selection of distribution monitoring sites | drinking water | The number and location of sites for monitoring of antimony in the distribution system, including sampling at the tap, should take into consideration the site-specific accumulation and release risk factors. | | high |
| #Q024 | operational | operational | recommended | Interpretation of discoloured water absence | drinking water | However, the absence of discoloured water should not be interpreted as the absence of a metals release. | | high |
| #Q025 | monitoring | operational | guidance | Reduced monitoring for distribution system | drinking water | Water utilities that have baseline data indicating that antimony is not present within the distribution system may conduct less frequent monitoring. | When utilities have baseline data indicating that antimony is not present within the distribution system | high |
| #Q026 | monitoring | health | recommended | Private well testing recommendation | drinking water | Households with private wells are encouraged to have their water tested for total antimony to ensure that the concentration in their water supply is below the proposed MAC. | Households with private wells | high |
| #Q027 | monitoring | treatment | recommended | Residential treatment device monitoring | drinking water | In addition, homeowners with private wells using residential treatment devices should conduct routine testing on both the water entering the treatment device and the treated water to verify that the treatment device is effective. | Homeowners with private wells using residential treatment devices | high |