How Do Our Water Systems Work?
Water is a renewable resource that is provided naturally through the earth’s water cycle, in the form of precipitation. While water is provided by nature, many of us rely on a complex network of pipes, pumps, equipment, and people provided by our community’s municipal water systems to safely deliver clean water to our taps, and remove used water from our homes and businesses.
There are 6 key stages in our municipal water systems:
- Source water – the lakes, rivers and underground aquifers that are the source of our water supply, fed by rain and melting snow.
- Water treatment – the processes to filter and purify water so that it is safe for human use.
- Water distribution systems – the pipes and pumps that deliver clean water to our taps. In BC there are more than 32,000 km of underground water pipes – that is enough pipe to circle 80% of the way around the earth!
- Wastewater collection systems – the pipes and pumps that take away used water from our toilets, drains, bathtubs, and laundry. These are also called sewers. In BC, there are over 26,000 km of municipal sewer pipes underground – that is enough pipe to circle two-thirds of the way around the earth!
- Wastewater treatment – the processes to remove contaminants from our used water so that it can be safely returned to the environment. This is also called sewage treatment.
- Stormwater systems – the pipes, ditches and natural systems that channel our rain water and snow melt away from our homes and businesses and back to the natural environment. In BC there are over 20,000 km of stormwater pipes underground – that is enough pipe to circle half way around the earth!
Where does our water come from?
In British Columbia, 91% of residents get their water from municipal water systems, 8% get their water from private wells, and 1% get their water delivered by tanker trucks into holding tanks.
86% of the water that feeds into municipal water systems comes from rivers and lakes – these are called surface water sources. 14% of the water that feeds into municipal water systems comes from underground aquifers – these are called ground water sources.
How does water get from the source to our taps?
In municipal water systems, water is withdrawn from the water source and treated before it is pumped to our homes and businesses. The quality of the source water determines the type of treatment method. Most systems will include several stages of filtration (to remove suspended particles, debris and algae) and disinfection (to remove bacteria and viruses and purify the water). Disinfection methods include chlorination and treatment with UV (ultra violet) light.
After treatment, municipal water systems distribute water to homes and businesses in large pipes called water mains that are usually buried under our roads and sidewalks. Water mains are maintained by our local governments, and paid for by water rates and property taxes.
Water lines are smaller pipes that transport the water from water mains to individual homes, apartments and businesses. Water lines are the responsibility of the property owner.
How do we know our water is safe to drink?
Water in municipal systems is required to meet strict water quality standards established in provincial regulations, and is tested regularly to ensure that it is safe to drink.
Where does our water go?
Common steps in municipal sewage treatment:
- Preliminary treatment
- This stage of treatment removes grit, like sand and gravel, egg shells, coffee grounds etc. from raw sewage. 12% of municipal sewage in Canada receives no treatment or preliminary treatment before it is discharged into the environment.
- Primary treatment
- This stage of treatment starts with temporary holding of sewage to allow the solids to sink to the bottom, and oil and grease to float to the top. The settled and floating material is removed, and the remaining liquid is moved to the next stage of treatment or discharged to the environment. 30% of municipal sewage in Canada receives preliminary and primary treatment before it is released into the environment.
- Secondary treatment
- This stage of treatment removes dissolved and suspended biological matter and the remaining liquid is moved to the next stage of treatment or discharged to the environment. 51% of municipal sewage in Canada receives preliminary, primary and secondary treatment before it is released back into the environment.
- Tertiary treatment
- In this stage of treatment, water is treated with chemicals and filtered prior to being released to the environment. 7% of municipal sewage in Canada receives preliminary, primary, secondary, and tertiary treatment before it is released back into the environment.
Stormwater is the result of rain or melting snow. Some of this water is absorbed by the earth and percolates down into underground aquifers, and some finds its way through ditches to streams and rivers that flow into lakes and oceans.
In urban areas, where the ground is covered by sealed surfaces such as roads, parking lots, or buildings, stormwater systems prevent flooding of our homes and businesses by collecting the water in storm drains and piping it to lakes, rivers and the ocean.
Stormwater is not treated before it is discharged to the environment. This means that contaminants and debris can wash into the system, and impact humans, fish and other wildlife that use the lakes, rivers and ocean areas where stormwater flows.