An aside: drinking water in Tas.

Local news items recently warned of problems with drinking water in Tassie towns and the list includes some places we visited. The tin dragon has, it seems, left a legacy of heavy metals and some other kind of dragon has tainted water supplies with unwanted organisms.

Residents of Scamander are reminded that a TEMPORARY boiling of drinking water alert is in place... Avoca, Pioneer, Ringarooma and Whitemark have been deemed unsuitable for drinking following the detection ... of heavy metals... Residents of Gladstone, Herrick, Ledgerwood, Derby, Winnaleah, Branxholm, Fingal, Mathinna, Cornwall, Rossarden, Mole Creek, Lady Barron & Lilydale are reminded that a PERMANENT boiling of drinking water alert is in place for this water supply....
http://www.benlomondwater.com.au/News/Alerts---Restrictions/Alerts---Restrictions

Water tanks are an obvious solution but hazards lurk there as well. One local manufacturer used lead solder to seal the seams of stainless steel tanks which have "lead levels well above safe levels set by public health guidelines". The tanks have no manufacturer's label and concerned owners are advised to get their tank water tested by a laboratory. I don't know how older metal tanks were sealed.
http://workplacestandards.tas.gov.au/safety/alerts/lead_contaminated_steel_rainwater_tanks

Cities and larger towns have their own problems which are expensive to fix, though we're reassured that the problem isn't an urgent one:

TASMANIAN councils might be stuck replacing hundreds of kilometres of water pipes containing asbestos, costing them tens of millions of dollars... `These are very low-risk assets and it would be unaffordable to replace them prematurely.' 
http://www.examiner.com.au/story/1394838/new-pipes-may-cost-millions/?cs=95

Cottage and water tank
(and the roof needs cleaning).

Plastic rainwater tanks would be preferable, provided the roof and gutters were suitable... and kept clean, which requires diligence and effort.

For us, the warnings are academic because we're out of the NE Tas housing market. I learned today that the little cottage is "under offer" and so too the owner's house, which was another option if we were considering a move. Both properties had water tanks and a connection to a local dam that supplied water of unknown quality via an unofficial network of plastic pipes. Truth be told, we were never in a stable-enough position to be in the housing market and that's the case now too.