Conservation Corner: Contrary to popular belief…..
I find it fascinating when a new study or event contradicts common practice, and maybe even common sense. An example is how we have learned that several decades of fire suppression in our forests now result in fires that burn hotter, faster and are more destructive than those of the past. Here are a few things I have come across that might lead us to question some common water conservation practices.
Some studies suggest that low-flow showerheads save water at the expense of increased energy costs. Most low-flow showerheads compensate for restricted flow by mixing air with the water. The air gives the water a ‘softer’ feel, eliminating the needle-like spray associated with those old, cheap low-flow showerheads. But, the air also cools the hot water perceptively, so the person in the shower responds by turning up the hot water resulting in increased energy use.
Have you ever triggered a sensor-operated faucet just by walking by? It happens. But, that is not the only reason sensoroperated faucets use 30-60% more water than manually operated ones. Most sensor-operated faucets are set to provide full-flow, while most people only turn on the tap halfway when washing their hands. Sensor-operated faucets also tend to run longer than manual washing. Sensor-operated faucets may be more sanitary than manually operated faucets, but they do not save water.
Automatic irrigation systems
Having an automatic irrigation system is far easier than watering by hand, but is it more efficient? In theory, a properlydesigned system should be more efficient than hand-watering. But, the system is only as efficient as the person who runs the
controller. A US study concludes that 92% of automatic irrigation timers are touched just twice a year: once when turned on in the spring, and once again when turned off in the fall. People with automatic irrigation systems tend to water longer and more frequently than people who have to drag hoses around.
The effectiveness of a rain barrel really depends on climate. Obviously, in rainy areas, rain barrels fill faster and more frequently than in drier areas. But, the irony is that landscapes in rainy areas receive sufficient moisture from the rain and do not need the supplemental water saved in the barrel. In dry areas, a rain barrel will not hold enough water to make much of a difference. On average, a rain barrel will save about 2.5 cubic metres of water a year. Does it really make sense for a homeowner to buy – or a municipality to subsidize the cost of – a product that saves so little water?
Odd/even watering restrictions
Odd/even is one of the most common forms of watering restrictions. They are easy for the homeowner to remember, and easy to enforce. But, do odd/even watering restrictions actually result in less water use? The US Department of Environmental Protection has this to say:
- “Odd/even day-watering and off-peak watering generally does not reduce overall water demand (and may actually increase overall demand), but can reduce peak demands. Such a restriction is only useful when the system generally has sufficient water quantity, but has system limitations in meeting peak demands.”
In some climates, odd/even restrictions condition homeowners to water more frequently than they need to. This does not mean that odd/even restrictions are not a viable part of a water conservation strategy, only that they should be chosen for the right reason, not because they are convenient. None of these studies prove that these water conservation methods are wrong, only that, in certain circumstances, some of them may not be as ‘right’ as we might think they are.
By Neal Klassen, BCWWA “Watermark” contributor
Originally published in the Spring 2009 issue of Watermark Magazine, the official publication of the British Columbia Water & Waste Association (BCWWA).
Posted April 2009