Residences and businesses often clean hardscapes such as driveways, sidewalks and parking areas by spraying them with a hose or pressurized washer, but little thought is given to how much water is being used and what can happen as a result.
A running hose uses about 10 gallons of water per minute, or 100 gallons in 10 minutes, and a power washer uses about two to five gallons of water per minute. Sweeping hard surfaces regularly and disposing of the material at the landfill instead of hosing or power washing it into streams and storm drains not only saves hundreds of gallons of water but also benefits water quality in area streams, rivers and lakes.
Many contaminants such as petroleum products (gas, oil or antifreeze), ice melt, fertilizer and pesticides, heavy metals, sediment and animal waste can accumulate on driveways, sidewalks, steps and parking lots. Cleaning hard surfaces with water can transmit these materials directly into storm drains and adjacent streams, entering waterways untreated. Many residents don’t realize that water running through storm drains in our community does not receive treatment prior to discharge. The result negatively affects drinking water, recreation, fisheries and wildlife.
Even small concentrations of some toxins can have widespread impacts. Nutrients introduced into rivers and lakes from sources such as fertilizers cause excessive weed and algae growth and, as a result, can reduce the amount of oxygen in the water, resulting in harmful effects on aquatic organisms and lake ecosystems.
Cleaning hardscapes with water is an example of unnecessary water usage that easily can be rectified with simple common sense practices. Just bring out the broom.
Lyn Halliday is an environmental scientist and owner of Environmental Solutions Unltd. She consults locally on environmental issues and was instrumental in the development of the Steamboat Springs Water Conservation Plan.