The reference is to a process that Indigenous Services Canada has whereby they do an annual risk assessment of the state of a water system, and 43% of them have been rated as high or medium risk, meaning that they likely haven't had their maintenance done or they perhaps don't have trained operators.
There's a set of criteria that allows the department to rate the state of a system. Forty-three per cent of them have rated “high”, which is an indication that perhaps there will be water advisories. It's at least an indication that you need to pay attention to those systems because maintenance is likely not happening the way it should be happening.