Grid Shutdown: Boil Water Advisory

If you have ever had a water main break on your street or any other service disruption to your water supply you may have experienced a Boil Water Advisory or a Boil Water Order. Boil water advisories/orders are the official response from the people running the water system. Below is a brief description of when a system would issue a boil water advisory or order and some general ideas for what should and should not be done as someone under a boil water advisory/order.

Source: districtgov.org

The good news about a boil water advisory is that they are often issued as a precautionary measure. Meaning they are often used in cases where the water isn’t actually dangerous. The system operators issue the warnings so they have done the proper due diligence. The liabilities involved if someone gets sick or dies and the public wasn’t informed are huge. Ok, at this point you may be wondering what sort of situations would require a boil water advisory. Typically any time there will be work on the distribution system requiring lowering the pressure or if the disinfection of the water system is interrupted for a long time.

Boil water orders are more serious. They come into place when large and persistent problems occur. Things like contamination of the source water and major failure of critical treatment equipment can cause boil water orders.

Boil Water Notice From The Regional District Of North Okanagan (source: vernonblog.blogspot.com)

The first thing you should do when you learn about a boil water advisory or order is read the information given to you. It will have instructions for you. It will have essential information for you like the cause if it is known and the expected duration. It will also list acceptable uses of the water, you might need to boil before drinking but washing is fine. Or you may not be able to use the water for gardening if the reason is due to chemical contamination. If you actually read the notice you will appear to have inside knowledge because in my experience very few people will ever read them. It will also list sources for alternative drinking water supply. Watch how fast the corner store sells out of water. In my experience, people only let this happen once. Then they start keeping a supply.  The written notice will usually only talk about “drinking” but the list of activities that require boiled water include food preparation, coffee makers (some don’t boil the water long enough or hot enough), brushing teeth, making ice, making infant formula and anything going into an immune compromised person.  Veterinarians also recommend that any water given to a domesticated house pet should also be boiled.  Livestock are a different story.  Anything that is already free range is already drinking untreated water and will probably be unaffected by drinking the unboiled water.  However, there is still a limit for bacteria concentrations in water consumed by livestock, free range or not, just like there is for every other animal (including us) on the planet.  Here is a link to the standards for water uses for the Province of British Columbia, use table 1 as a guidline for how to use water during a boil water advisory or boil water order.  If table 1 says “no applicable standard” then it is safe to use the unboiled water. http://www.env.gov.bc.ca/wat/wq/BCguidelines/microbiology/microbiology.html#toc

The biggest thing you should not do is abandon drinking tap water in favor of bottled water. This is a mistake. If you do this you are still at risk but you are significantly less likely to hear about it if something is wrong. Another thing to avoid doing is panic. This is one of those things where no news is good news. I tell the people that if you stop seeing me and hearing from me then everything is back to normal. This is because I am legislated to tell the public when there is a problem. At this time I also tell them the time line as does the written notice. After two consecutive clean water tests the system and water return to normal. It is also way too time and cost prohibitive to go back door to door and say “everything is fine now”.
If you live in a large city, there will probably be some media coverage of the return to normal situation. Otherwise if you don’t hear anything. After the date on the notice your water is fine. If there is still a problem they are legally required to tell you again about the problem.  Neither a boil water advisory or boil water order is something to panic about it is not time to call a well driller and go off the water system completely (if that is even an option where you live). It is time to start using your preparations and your backup water supplies.

If you don’t want to or can’t boil your water then you can always use an alternative form of disinfection.  Either ultraviolet radiation, sodium hypochlorite or calcium hypochlorite are acceptable alternatives.  Be careful of using these alternatives for highly turbid water sources.  The floating debris in the water can hide pathogens, cryptosporidum is highly resistant to chlorine as is girarda adding enough chlorine to kill these two microorganisims will make the water unsafe to drink.  Turbidity can also react with the chlorine to form hazardous chemical byproducts. Remember turbidity is removed from the water by setteling and filtering before disinfection to avoid these two problems. You may want to install a water filter in your home or purchase a portable water filter as a backup.

All that is left is what needs to be done after the boil water notice or order is lifted and everything returns to normal.  Flush all water-using fixtures like faucets and showers for at least one minute. Drain and flush all ice-making machines in your refrigerator. Run water softeners through a regeneration cycle.  Drain and refill hot water tanks set below 45 C (normal setting is 60 C). Change any filters either under sink style, on the faucet style and the ones in a jug in the refrigerator, regardless of the type of filter.  Filters that are designed for untreated water will not need to be changed unless they are used up.

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Disinfection with Calcium Hypochlorite

This journal entry is a continuation of my series of entries on disinfection of drinking water.   Please read the following linked articles first,  Introduction to Disinfection and Disinfection with Sodium Hypochlorite.  I have covered a lot of background information already, which you will need to fully understand this journal entry.    Go ahead, I’ll wait.

Calcium Hypochlorite, Ca(OCl)₂ is a solid chemical used as a disinfectant and bleaching agent. It is used to store chlorine for long periods of time without having to resort to chlorine gas, which is extremely dangerous if not handled properly.  If stored is a room temperature environment away from moisture, temperature extremes and direct sunlight, calcium hypochlorite can last up to a year without serious degradation.  Beyond a year the chemical will become weaker with time.

Calcium hypochlorite is very similar to sodium hypochlorite.  The biggest difference is Continue reading