Roof-collected rainwater fails health test

Drinking water from your roof carries a significant risk of illness, according to a five-year study from Massey University.

More than half of 560 samples from private dwellings in New Zealand exceeded the minimal standards for contamination and 30 percent showed evidence of heavy faecal contamination.

“I’m utterly amazed at the number of roof water supplies that fail the New Zealand drinking water standards,” says Stan Abbott, a microbiologist at the Institute of Food, Nutrition and Human Health.

Roof-collected rainwater consumption is popular because the public believes that rainwater is pure and safe to drink, says Mr Abbott, who is Director of the Roof Water Research Centre at Massey’s Wellington campus.

More than 400,000 New Zealanders depend on roof-collected rainwater systems for their drinking water, especially those living on farms, lifestyle blocks or baches that are not served by town water supplies.

The likely sources of the contamination were faecal material deposited by birds, frogs, rodents and possums, and dead animals and insects, either on the roof, gutters, or water tank. Contamination can lead to gastrointestinal diseases from pathogens including salmonella, campylobacter, giardia and cryptosporidium.

“Simple steps such as installing down-pipe debris screens and a first-flush diverter will reduce the risk of contracting waterborne diseases,” he says. A first-flush diverter is a device that reduces contamination of the tank water by diverting the first flush of contaminated water after a rain-fall event so that contaminants do not enter the tank. Recent research at Massey University has shown spectacular improvements in water quality in the storage tanks linked to first flush diverters.

While relatively few disease outbreaks linked to contaminated roof-collected rainwater have been reported in New Zealand, Mr Abbott says indications are that there is massive under-reporting of illnesses associated with contaminated roof water.

“The lack of evidence linking illness and poor quality roof water inhibits moves to improve systems delivering rainwater for consumption.”
Although it is the homeowner’s responsibility to ensure drinking water is clean, he says information on the safe collection and storage of roof-collected rainwater seems not to be reaching many people.

“Accurate communication of the health risks of contaminated roof water is necessary so that the consumers can manage the risks.”

The Building Act requires premises to be provided with potable water for consumption, oral hygiene, utensil washing and food preparation. Under Section 39 of the Health Act it is illegal to let or sell a house unless there is a supply of potable water.

Roof-water users can reduce their risks of disease from contaminated rainwater consumption by regular maintenance and using a well-designed system, says Mr Abbott.

Source: Massey University

Related stories:

Backyard gardens need good food-safety practices, too
The recent tomato contamination outbreak has many people thinking about growing their own garden-fresh fruits and vegetables. But a food-safety specialist in Penn State's College of Agricultural Sciences says it's not where the produce is grown, but how it's grown, so amateur cultivators should know a few important tips about home-garden food safety.

New research house to guide future home development
The University of Nottingham is helping to battle climate change on the home front -- with the construction of a new experimental house on campus that will cut 'greenhouse gas' emissions by 60 per cent.
Rain gardens touted as pollution removers
University of Connecticut scientists say properly designed "rain gardens" can trap and retain up to 99 percent of common pollutants in urban storm runoff.
Water: The forgotten crisis
This year, the world and, in particular, developing countries and the poor have been hit by both food and energy crises. As a consequence, prices for many staple foods have risen by up to 100%. When we examine the causes of the food crisis, a growing population, changes in trade patterns, urbanization, dietary changes, biofuel production, and climate change and regional droughts are all responsible. Thus we have a classic increase in prices due to high demand and low supply.
Mars air once had moisture
A new analysis of Martian soil data led by University of California, Berkeley, geoscientists suggests that there was once enough water in the planet's atmosphere for a light drizzle or dew to hit the ground, leaving tell-tale signs of its interaction with the planet's surface.
Africa's deserts could supply solar electricity to continent: experts
Solar power from Africa's deserts could supply all 600 million citizens currently without electricity and even export power to Europe, a green energy conference in Nairobi heard Thursday.
Scalable wind turbine might fit on your roof
When you think of wind power, you probably picture gigantic wind turbines spinning gracefully in the middle of large open areas.
New cell-based sensors sniff out danger like bloodhounds
A small, unmanned vehicle makes its way down the road ahead of a military convoy. Suddenly it stops and relays a warning to the convoy commander. The presence of a deadly improvised explosive device, or IED, has been detected by sophisticated new sensor technology incorporating living olfactory cells on microchips mounted on the unmanned vehicle. The IED is safely dismantled and lives are saved.

News discussion:

Importance of not saving first of rainfall. in Medicine & Health news