YOU attach it underneath the tap and when you sip your glass of water you can rest assured that the contents are virtually fluoride-free.

However, the contraption – a reverse osmosis filter system – doesn’t come cheap at $650.

But it is a price some Mackay residents are willing to pay as they prepare for ‘F-day’, which will officially arrive tomorrow.

Sales of the nifty filtration system at Dowdens Pumping in Mackay have picked up over the past month as people prepare for the introduction of fluoride to our water supply.

And sales manager David Dowden said it wasn’t a bad option for those who weren’t big on the F-word.

“It takes soluble items out of the water,” he said.

“It will do up to 95 per cent (of fluoride) and there are other cartridges that will do it at 75 per cent.”

The filtration system can produce up to 190?litres of drinking water a day.

Mr Dowden said six of the systems had been sold in the last month but he expected more to fly out the door when fluoride was introduced tomorrow.

“Definitely, the demand has increased,” he said.

“The adding of fluoride to the water has created a lot of interest.”

North Mackay resident Bob Hollis said he invested in a reverse osmosis filtration system because he was concerned about how much fluoride he could end up consuming.

“How do we know what dosage is going in? How are we going to check?” he asked. “The idea of putting a class seven poison in our water and calling it a health initiative is just crazy.”

The World Health Organisation is one of numerous international health institutions to endorse the practice of adding fluoride to drinking water to improve dental health.

The Nebo Road water treatment plant is required to add between 0.6 and 0.9 parts of fluoride per million parts of water – the equivalent of one drop in a tub of bathwater.

The introduction of fluoride is part of a $24?million upgrade to the plant that will increase water capacity from 55?mega litres to 75?mega litres.