In Depth
Going green
Reusing water
Don't throw out the bath water
Last Updated July 11, 2007
By Sabrina Saccoccio, CBC News
There's one on nearly every block: The neighbour with the coveted lawn and irrigation tendencies that could sustain a major agricultural crop.
The grass is always greener, until a summer water shortage hits, and that neighbour has to shut off his sprinklers — or be fined.
In Calgary, for example, failure to stop watering comes with a penalty of $200 to $2,000. Bans usually limit sprinkler use to every other day. Complete bans restrict lawn watering entirely. And forget topping up the swimming pool or washing cars.
One solution is to douse the lawn with recycled household water. This may sound unhygienic, but according to water experts, it actually isn't. In fact, the murky stuff washed down the drain after a bath or once the dishes are done can be cleaner than groundwater found in some major Canadian cities. Sweden takes it one step further, using urine to fertilize farms.
In Canada, recycled water is also used to flush toilets. Similarly, heat from household water going down the drain is captured to keep morning showers bearable.
A recent study found more Canadians are using these kinds of water conservation techniques. According to the Statistics Canada study released Wednesday, nearly a quarter of homes with lawns used water sprinkler timers, while rainwater was also being collected. Barrels or cisterns were placed outdoors in 14 per cent of Canadian homes. Saskatchewan and Alberta collected rainwater more often than other places, with a rate of 28 per cent.
"We assume these are being reused," said John Marshall, senior Statistics Canada analyst, "given that both [barrels and cisterns] are used to conserve water whether you're drawing from it to water your lawn or the garden."
How does rainwater collection work to recycle water?When reserved in large barrels or cisterns, rainwater can be used to hydrate lawns in drier times. But pools of water sitting around for too long encourage mosquitoes that can spread disease.
A safer way to collect rainwater is to make wells in the soil around trees, and to sink plant beds below grass level so water can amass.
Experts also suggest landscaping backyards so runoff flows toward trees and plants. When patios and pathways are on higher ground than soil, rainwater is more usefully directed.
What are other methods of water reuse?
Water used in showers, for laundry, in sinks and to do the dishes is all reusable providing it contains only biodegradable soaps and detergents. Environmentalists refer to it as "greywater." It doesn't include what's flushed down the toilet; that's known as "blackwater."
In some cases, 80 per cent of water that leaves the home can be used again.
"It relates back to the nutrient stream. We are what we eat, and in a perfect world the water we use would go back to the land," said Mario Kani, a professional engineer and president of Sustainable Edge, a company that designs greywater systems.
What can recycled water be used for?
Although it's not clean enough to drink, recycled household water can be used for lawns and gardens that don't have food crops. Hoses from the tub or sink can be installed to filter recycled water into the backyard.
This method is actually better for the environment than sending recycled water out as effluent to rivers and harbours. Contaminants in recycled household water affect bodies of water more than they do ground water.
Putting recycled water into the soil is good, but using it on plants, which help to further clarify it, is even better.
As Kani explained, "Roots have a great capacity to clean water contaminants but they also contribute nutrients because they actually feed the plants."
Water is purified when pumped through plant root systems, he said.
In his own home, Kani uses a heat exchanger to warm cold water coming into the shower. Much like solar panels collect warmth from the sun, exchangers reclaim heat from water washed down the drain.
How are recycled water systems set up?
Not many homes have water recycling systems because they are difficult and expensive to install. The cost of retrofitting an older home isn't worth the savings in water use. "You'd have to rip up ceilings and do some major plumbing," Kani said.
But with newer homes it's worth the work. It means using separate pipes for toilets. In most homes, water washed out of both drains and toilets goes into one pipe that takes it to city service.
For Kani, his increasingly pricey heating and water bills are enough reason to switch.
With municipalities finding it more expensive to provide fresh drinking water, recycling it might become a necessity down the road. The United Nations Educational, Scientific and Cultural Organization (UNESCO) has predicted a major world water shortage by 2020.
A typical pump to shuttle shower water to the toilet can be about $1,500 (not including the labour costs to install it).
A pump like this can cut fresh water use by a third. As of 2001, the average Canadian used more than 345 litres of fresh water every day, mostly in the bathroom. That number was the second-highest in the world next to usage in America.
Are there building code laws for recycled water use?
Municipalities generally categorize all water leaving the home as sewage, making recycling systems illegal in some areas.
In most places, recycling water and reusing it on lawns means proving it's not contaminated.
On the other hand, some governments reward people who install these systems. In arid places like Arizona, the government reimburses residents 25 per cent of the costs of water recycling equipment.
But plumbing renovations, no matter how small, require building permits, and each community has its own standards for code.
What other methods are being used?
In Sweden, a test market in the council of Tanum is recycling urine for use as fertilizer on farms. All new homes in the area are required by law to have special toilets that separate urine and pipe it into a holding tank that farmers access at regular intervals.
Experts say this is better for the environment because the special toilets use less water. And less energy is utilized at treatment facilities.
Most importantly, human urine has the most concentrated source of phosphorus, which is a vital ingredient in agricultural fertilizer. Tell that to the neighbour with the great lawn.