BC, Canada: Safe Water Supply, Vital To Your Health – 1995

This report dated 1995 from the Ministry of Health and
Ministry Responsible for Seniors explains how to solve your drinking water quality issues. The report advises consumers to disinfect your supply of hauled water (collected during an emergency) to counteract possible contamination from handling or transporting. Click here to read the entire report or an excerpt below.

Do not assume that clean-looking water, especially water from a spring, surface
source or shallow well, is safe to drink.

Test all water sources for “indicator” bacteria (ie. coliforms). Most indicator
bacteria do not cause any health problems themselves, but their presence means
that the water has been contaminated and may contain other bacteria, viruses or
parasites which could cause illness. The most common indicator bacteria are
coliform bacteria.

There are two basic types of coliform bacteria that labs commonly test for: “total
coliforms” and “fecal coliforms”. Total coliform bacteria include many bacteria
which grow in water, soil or in the digestive systems of animals. Fecal
coliforms generally grow and multiply only in the digestive systems of
warm-blooded animals.

The presence of total coliforms means that water has been contaminated and, when
found at your tap, that your treatment system isn’t adequately purifying your water.
Drinking water should not have many coliform bacteria– by law in British
Columbia public water systems should never have more than ten total coliform
organisms in a 100 millilitre sample, and no more than ten percent of samples
should have any total coliform bacteria.

Fecal coliform bacteria are a type of total coliform bacteria which grow and
multiply in the intestines of an animal. Their presence in your water supply means
that fecal material is getting into your water system. Because of the large number of
diseases and parasites which are spread in animal and human feces, no amount of
fecal bacteria are acceptable. If your source water contains fecal bacteria you must
disinfect the water supply. If samples taken from your tap contain fecal bacteria,
you are either not using enough disinfectant, or it is not in contact with the water
for long enough before it gets to your tap.

Surface water quality is continually changing and is always at risk of contamination
by animal feces and therefore needs to be disinfected regardless of periodic lab
results which show little or no contamination. Test all new water sources for
coliforms and chemicals.

Test your water regularly, especially for bacteria.

Solving Water Quality Problems

Controlling Bacteria
When your water source is surface water, a shallow well or a spring, install a
disinfectant system to continuously disinfect all water entering your distribution

Disinfect your system whenever you construct, repair or accidentally contaminate a
water system.

Softening Water

Select a reputable product and dealer.

Choose a size related to factors such as the amount of water used and the hardness
of the water.

You may want to provide a separate unsoftened water supply for drinking and

Removing Iron and Manganese

Install an aerator to help remove iron and manganese.

Use green sand filters to remove low iron and manganese concentrations.

Controlling Iron Bacteria

Well water can become contaminated if the well is sunk into rock which contains
natural iron. Some bacteria can cause the iron to precipitate out of the water as a
redish fleck. This won’t pose a health threat but iron can cause taste and odour
problems and staining of sinks, toilets and laundry.

Periodically disinfecting your well may help.

Controlling Lead

Lead in drinking water systems is usually caused by aggressive water acting on the
lead solder in your plumbing – when water sits in soldered pipes overnight or for
longer periods it may dissolve some lead from the solder.

Run water in the morning for several minutes until it is cold.
You may want to consider replacing old pipes, or install a limestone contactor
system (page 16).

Removing Hydrogen Sulphide

A rotten egg smell usually means there is hydrogen sulphide in your water.

Install an aerator to help oxidize dissolved hydrogen sulphide to solid sulphur, and
then remove the solid sulphur with a sediment trap or activated carbon filter.

Alternately, you can add chlorine bleach to the well to “oxidize” the dissolved
hydrogen sulphide to solid sulphur and to kill bacteria which may be converting
sulphur to hydrogen sulphide in the well. Again, remove the solid sulphur with a
sediment trap or activated carbon filter.

Replace activated carbon as necessary.

Removing or Reducing Gas (Methane)

If your well is giving off natural gas (methane) you should seal the well head at the
top and install an air vent that lets the gas escape at least 2.4 meters (8 feet) above
ground level.

Install an aerator and activated carbon filters to remove gas that may have been
absorbed into the water.

Removing Gas and Oil

Clean up by pumping the contaminated layer to waste and install an activated
carbon filter to remove small amounts of oil or gas.

Consider using an alternative source of supply (eg. bottled water) until the problem
is resolved.

Oil material may come from your pump – check to make sure your pump is not

Reducing Cloudiness (turbidity)

Contamination which causes cloudiness may contain disease–causing bacteria,
viruses or parasites. You should always treat cloudy water to remove these
organisms. In-line filters may be effective for slightly turbid water, but may clog up
if the water is excessively turbid.

Alum, when added to cloudy water, will cause particles of clay, silt or other matter
to settle. To use alum effectively your water system must have a settling pond.

Controlling Fluoride

Test your well water for natural fluorides – concentrations above 1.5 mg/L may
cause mottled teeth and other health effects.

If natural fluoride levels are below 0.7 mg/L, ask your dentist about the use of
fluoride supplements.

If the concentration is higher than recommended, you may be able to treat the water
chemically or through reverse osmosis or distillation.

Controlling Arsenic

Test your well water for arsenic when first installed, and then periodically every
five years. Arsenic is a naturally occurring element that has been found at elevated
concentrations in some areas of British Columbia.

Should you find elevated arsenic, consult an Environmental Health Officer about
ways of reducing arsenic levels, including reverse osmosis, distillation, and other
point-of-use devices.

Consider developing a new well in a different location, or finding another source of
supply, including bottled water.

Controlling Nitrates and Nitrites

Nitrates and nitrites are chemicals which are formed from the decomposition of
organic matter.

Protect water sources, especially shallow groundwater aquifers from contamination
by nitrates and nitrites. Common sources of nitrates are fertilizers, barnyard wastes,
septic systems, municipal and industrial waste water, and leachate from garbage

Nitrates and nitrites reduce the ability of the blood to carry oxygen. This is not
normally a significant problem for adults, but children less than 6 months old are at
increased risk. See Health File #5 – “Nitrate Contamination in Well Water”
available at your local Health Unit.

Consider developing a new well in a different location if elevated nitrate levels are
found in your well.

Controlling Corrosive Water

Filtering corrosive water through crushed limestone in a 200-litre (45 gallon)
contact chamber will decrease corrosiveness. The contact chamber should be
designed to allow water to be in contact with the limestone for 30 minutes to one
hour at maximum flow rates. If possible, the contactor should be the last treatment
component before the water enters the house. Limestone contactors will be most
effective with very soft waters (i.e., with a pH of 6 or less).


It may be necessary to disinfect your well if bacteria tests show that it has become
contaminated. Even if you prevent further contamination of your well, the bacteria
that have already gotten into it can cause ongoing water quality problems.
Problems which can result from bacterial contamination of a well include an
increased risk of illness and the production of unpleasant tastes or odours.


Giardiasis (Beaver Fever) and Cryptosporidiosis are gastrointestinal diseases which
may be contracted through consumption of water which has been contaminated by
animal or human feces (See Health File #10, available at your local Health Unit).
The organisms which cause Giardiasis and Cryptosporidiosis have been found in
surface water supplies such as streams, rivers and lakes throughout North America,
and have been found in British Columbia surface waters as well.

Giardia and Cryptosporidium (the organisms which cause Giardiasis and
Cryptosporidiosis) are parasites which can form a thick-walled cyst to resist
environmental stresses and are therefore more capable of withstanding disinfectants
than pathogenic bacteria. The safety procedures outlined here are recommended
to ensure safety against contamination by these highly resistant
disease-causing organisms.

Assume that your water supply has been contaminated if floods or earthquakes
strike your property. Don’t drink the water until you have adequately treated it.

Disinfect water if you suspect any contamination of your supply.

Disinfect all water that will be used for;
• drinking;
• cooking;
• brushing teeth;
• washing dishes; and
• washing fruit and vegetables to be eaten raw.

It is especially important to make sure that any water used to make infant formula
is disinfected.

Let muddy or cloudy water settle before disinfecting (or, preferably, use a different
source of water).

Pour off clear water into a separate container before disinfecting. It sometimes
helps to filter the water through a clean cloth.

Hauling Emergency Water

In an emergency, haul safe water from a public supply as an alternative to treating
your own water.
• Clean and disinfect all water containers and other equipment with a solution
10 times stronger than the solution used to treat water.
• Do not use containers which have held oil, sewage, pesticides or
other chemicals.
• Disinfect your supply of hauled water to counteract possible contamination
from handling or transporting.


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