Tanis Gower
Special to The Record
Why are we boiling our water?
If you are like me, hearing about another boil water advisory makes you want leave town until it is all over. Why have we had five boil-water advisories over the last two winters? Why is our water dirty? Do we really need to boil it? Why is the Comox Valley having these problems while other towns are doing just fine?
Our Comox Lake watershed was known for its high-quality water. Until the problems of 2014 and 2015, the water was typically so clean that Island Health (formerly known as VIHA) gave us a deferral for their updated filtration requirements. While this still meant we had to upgrade to ultra-violet disinfection to meet modern standards, we were going to save money by avoiding filtration. Now, we don’t have a choice, and we are on the path to a costly filtration plant.
Only those water supplies that have very high quality water, and that have effective and ongoing watershed protection are allowed to go without filtration. High quality water has low amounts of bacteria and other pathogens (which in any case are later killed by chlorination), as well as low levels of cloudiness - otherwise known as “turbidity”. It’s this last point – turbidity – where we are failing Canadian guidelines, though our level of watershed protection is also up for discussion.
Until we have filtration, Island Health will continue to issue boil water notices when our water passes a certain threshold of turbidity, which in our case is caused by small particles running off the land during intense rain storms. Despite the fact that water must be boiled when it is turbid, there is little to no relationship between turbidity and harmful bacteria. In fact, during times of higher turbidity, University of Victoria researchers found that there were lower concentrations of bacteria in Comox Lake, due to dilution by so much more wintertime water. The problem is that harmful bacteria can hide from chlorination when there are particles in the water, making water treatment less effective.
Our longest boil water advisory – lasting seven weeks over the Christmas holidays of 2014/2015 – was due at least partly to extra water eroding the clay banks of Perseverance Creek. This was a human-caused problem, as a poorly-designed water diversion system was spilling more water than the banks of Perseverance Creek could handle. While poor design was part of it, it is likely that climate change is playing a role, too. Extreme rainstorms are becoming more common, and we can expect more intense rainfall events in the winters to come.
The water flowing into our homes has thus far tested clean for indicators of harmful bacteria. However, sampling can be done on only a tiny fraction of the water used. As the agency responsible for public health, Island Health will tolerate only the smallest level of risk – hence the boil water advisory. After all, clean water helps keep us healthy. Water treatment is one of the biggest health advances of all time, and is a major reason for the almost-doubling of our life expectancy over the last century or so.
Making our water safe requires an ongoing conversation about how to treat our water, and our watershed. As authorities struggle to identify the precise causes of our turbid water, many community members want to know who is at fault. After all, the drinking watersheds of larger communities like Victoria and Vancouver are completely protected from human activity, while most of our watershed is not protected at all.
Shouldn’t the land users be shouldering some responsibility here? That’s one reason that a Watershed Protection Plan is being released this month. More on that in next month’s column.
Tanis Gower has been working to restore aquatic ecosystems and advocate for good water policies for the last 20 years. She is a Registered Professional Biologist from the Comox Valley who works on projects for Watershed Watch Salmon Society, local government, and others.