Residents of one Tasmanian town have been dealing with contaminated water for over eight years, and will continue to do so.

New tests have revealed contamination persists in the drinking water for the town of Pioneer, in the state's north-east, which has plagued by water woes for years.

The town’s tap water was first deemed unfit to drink in 2012, sparking concern among residents who believe they may have been exposed to unsafe levels of lead for years before being warned about it.

TasWater installed drinking water tanks at properties within the town as a solution, and has been supplying many with bottled water supplies for all uses – cooking cleaning and bathing.

In 2014, TasWater commissioned tests of roof paint on properties in Pioneer to look at the content of lead in the paint.

Some of the properties had lead content well above the current limit in the Australian Government's Department of the Environment and Energy guidelines.

In some cases, TasWater went on to connect the water tanks to the roofs, claiming to have misread the test results.

After the mistake was uncovered, TasWater disconnected the water tanks from the roofs began supplying bottled water.

The most recent routine testing of 36 properties in the town saw six return lead levels that were borderline or higher than the Australian Drinking Water Guidelines (ADWG).

TasWater has again advised the residents to stop drinking the tank water and provided bottled water.

The authority says it is still investigating the cause of the lead found in some of the tanks.

“Some of the tanks that returned lead levels borderline or higher [than the ADWG] are filled by roof collection systems which indicates that trucked water is not the cause of the issue,” a TasWater spokesperson said.

Mayor of Dorset Council Greg Howard believes it is a one-off event.

“I think the problem was caused by the fact that some of those tanks didn't have a tap in the bottom for TasWater to do the sampling,” he said.

“As I understand it, when they put those taps in, their view is that they disturbed the water potentially in the bottom of the tank and there may have been some heavy metal residue on the bottom of the tank which caused the issue.

“It's been an ongoing saga and it's been disappointing to be in that situation in the first place for the residents, obviously, and I can understand why they're upset and not happy.”

The State Government has plans to reintroduce a piped supply of drinking water within the next three years.

Cr Howard wants it to happen sooner.

“It's my understanding that TasWater have had someone in the town just recently looking at potential sites for a treatment plant so I think three years is the maximum,” he said.

“I don't necessarily think it is going to be three years.”

Meanwhile, TasWater is left spending over $1,000 a month on bottled water for some of the town's residents.