It is an emergency measure by the Department of Defence to provide alternative supplies to properties in the vicinity of the base after the detection of contaminated water.

Dangerous chemicals leached from the RAAF Base at Tindal between 1998 and 2004 to reach Katherine’s water supply.

A group of chemicals called PFAS were used in firefighting foam at Tindal which has now contaminated groundwater in the area.

The Department of Defence’s further testing of local groundwater is expected to be known in a year.

Five neighbours were supplied with emergency supplies after the contamination was revealed and that number has now grown to 51.

A department spokeswoman said the supply of rainwater tanks to Tindal’s neighbours was being considered “on a case-by-case basis”.

Writing in yesterday’s Katherine Times, Michael Bolton of Collins Road said recent testing of his bore for PFAS has come in at 4.56; almost 10 times the recommended level for humans.

“My family have unwittingly being ingesting this toxic bore water for the last 15 years,” Mr Bolton wrote.

Mr Bolton said his own research revealed concerns about the health dangers of PFAS.

“For the record, PFAS/PFOA do cause cancers, they are persistent in the environment with a predicted 40 year half-life and they will manifest in the food chain. They will accumulate in people,” he said.

The chemicals, known as PFAS, have also been found in Katherine’s tap water which has subsequently been cleared the NT Health Department as being at safe levels.