Can you imagine a city without water? We use it
for drinking, cooking, and for other household needs. In 1998, Canadians,
on average, used 343 litres of water per person per day. Water is
also needed to clean our streets, fight fires, fill public swimming
pools, and water lawns and gardens. And then, where would this water
go without a sewerage system? It is not surprising that some of
the oldest infrastructure built by human society consisted of aqueducts
and sewerage systems. Even in Canada, many cities still use parts
of water systems that were built not long after the cities were
first settled.
Municipal water use refers to all water supplied by a municipality
for its residents, businesses and industries. Although municipal
water use is a small part of water consumption in Canada (just 11%
of all withdrawals for 1991), it is the most visible use for most
Canadians.
Sources of Municipal Water
Across Canada, nearly all of the water used by municipal water
systems comes from lakes and rivers, the remainder (12% of the total)
comes from groundwater. In many places, water is distributed through
a series of pipes connected to a municipal water supply system.
In smaller centres and in rural areas, it is usually obtained from
wells. Water supply systems typically have intake, treatment, storage,
and distribution components. Rural residents usually have individual
groundwater supplies. Wells must be carefully prepared and maintained
to prevent pollution.
In some remote areas, water is delivered by trucks. For example,
in the far North, water may have to be trucked to homes that do
not have conventional water supplies because the ground is frozen.
Water is also delivered by truck in some rural areas where shallow
wells tend to go dry.
Where there are piped systems in the North, the pipes are often
buried well below the surface (up to 3 or 4 metres down) to get
below the worst of the frost. The pipes are also insulated to prevent
the water from freezing.
In permafrost areas, there is a different problem. The heat lost
from even insulated underground pipes would melt the permafrost
and cause the ground to cave in. Therefore, above-ground utilidors
(insulated boxes) are used to carry water pipes and sewer pipes
to individual residences. These pipes may also carry hot water for
heating. The utilidors are heated, insulated, metal or wood-clad
enclosures that are generally installed on piles or blocking.
Cost of Water
Establishing and maintaining water systems is costly. There are
three major costs:
- Water supply: Water usually has to be pumped,
stored, moved and treated to make it available in safe form for
consumers. It then has to be taken away after use. At all of these
stages, infrastructure is needed.
- Infrastructure maintenance: Maintenance includes
on-going maintenance, but also periodically being upgrading and
being increased in capacity.
- Administration: There are numerous overhead
costs in running a water system.
Water prices across Canada are generally low compared to other
countries. Based on 1996 data, the average household pays $27.65
per month, and uses about 30 000 litres per month, for water delivered
to the residence. Monthly bills range between $15 and $90, the lowest
being in Quebec, Newfoundland, and British Columbia, and the highest
in the Prairie provinces and northern Canada.
Although the operating costs for trucked-in water service are very
high, the lower capital costs make it more economic than piped service
for most northern communities. Consumption is much lower for areas
with trucked service, about 200 litres per capita per day in the
Northwest Territories and Nunavut.
Patterns and Trends in Municipal Water Use
Figure 1 shows user-categories for municipal water use in Canada
as a whole. The majority of consumption is done by residences. In
fact, residential use is larger than shown here
as the "commercial"
category includes consumption by apartment buildings. Note that
a disturbing 13% of water provided is lost through leakage.
[D] Click for larger version, 2 KB Figure 1. Municipal Water Use by Sector, 1994
Figure 2 gives a further breakdown of the residential sector in
order to show how people use water within a house. Personal washing
and toilet use make up about two-thirds of the total. It is not
surprising that water conservation programs have focussed on these
uses, stressing new technology such as lower-capacity toilets, and
water-saving shower heads.
[D] Click for larger version, 2 KB Figure 2. Residential Water Use in Canada, 1999
Figure 3 shows trends in municipal water use over time. The data
shows results of surveys conducted periodically, at the years shown.
The total water use is made up of data from municipalities that
responded to the survey in a given year plus a regional estimate
for municipalities that did not supply data (or were not surveyed).
Details are given in the State of the Environment (SOE) Technical
Supplement noted as a source.
[D] Click for larger version, 3 KB Figure 3. Daily Municipal Water Use per Person, 1983 to 1999
In Figure 3, the user can see that daily per capita water use in
the municipal sector declined by almost 10% in the period 1989 to
1996 (from 694 litres to 628 litres). After 1996, consumption climbed
slightly due in part to piped water systems replacing some groundwater-based
systems. The figure was 638 litres per person per day in 1999.
Although water usage rates vary across Canada, the overall per
capita use is very high compared to that in other industrialized
countries. Only the United States has higher rates of municipal
water usage.
|