A MAJOR study of rainwater tank quality in Brisbane has found it good enough to drink. The $600,000 study by Brisbane City Council on 29 rainwater tanks found the water met Australian Drinking Water Guidelines in most cases.

Final results will be released in July. However, the study found fecal coliforms and e.coli within acceptable levels, except where animals and foliage polluted the roof-top water source.

Water was even considered “pure” in two of the tanks which underwent monthly monitoring by the Scientific Analytical Laboratory.

Under the trial, homeowners within a 12km radius of the CBD paid 50 per cent of the cost of fitting rainwater tanks, dual flush toilets, AAA-rated shower roses, water pressure limiting devices and energy-efficient light globes.

The tanks were plumbed to the toilets, outdoor hoses and hot water systems.

Results from the study are being used to develop national water tank guidelines.

It has already resulted in plumbing and drainage legislation being changed to include rainwater as a source.

A council spokesman said the study found the water was not “pristine” but had very low concentrations of micro organisms.

Despite this, the council is refusing to declare it fit to drink.

“This is not a scientifically controlled process, with rainfall catchment surfaces exposed to birds, pollutants, leaves, possums, bats, insects and dirt” he said.

In the highly contaminated tanks, bacteria counts reached “the hundreds to thousands per 100ml”.

The 2004 national drinking water guidelines stipulate safe levels at less than one organism per 100ml.

The Australian Conservation Foundation has called on all governments to set targets to increase rain water tank rollout across the nation by 5 per cent a year.