When Gary and Karen Breadsell first bought their dream retirement home in Bullsbrook in early 2015, they could not have imagined it would lead to them joining a national class action against the Department of Defence.

Key points: A class action has been filed addressing PFAS contamination in WA

A class action has been filed addressing PFAS contamination in WA Residents in Bullsbrook have been hit hard by PFAS used at a nearby air base

Residents in Bullsbrook have been hit hard by PFAS used at a nearby air base The class action demands compensation for property value losses

But neither the Breadsells nor their fellow residents in the small semi-rural community, which nestles around the Pearce air base on the outskirts of Perth, knew about the water contamination at the heart of the suit filed by Shine Lawyers in the Federal Court on Thursday.

They are among more than 40,000 Australians included in the class action over alleged property value losses due to contamination by toxic firefighting chemicals, known as PFAS, used at defence bases around the country.

It includes people living near bases in Wagga Wagga and Richmond in New South Wales, Wodonga in Victoria, Darwin, Townsville in Queensland and Edinburgh in South Australia.

They are hoping to replicate the success of other PFAS class actions launched on behalf of property owners around bases in Katherine in the Northern Territory, Oakey in Queensland and Williamtown in NSW.

Defence agreed to settle in February but the Federal Court has yet to approve the agreement, including $212.5 million for Oakey and Katherine residents.

Legacy issues with toxic chemicals from firefighting foam in waterways remains a national issue. ( Supplied: CRC CARE )

The new class action was due to be lodged last year but was delayed because of a High Court judgement which created uncertainty over how class actions are funded.

As a result, Shine ran a strong grassroots campaign — including a community sausage sizzle in Bullsbrook — to encourage plenty of affected people to sign up and convince the litigation funder, LCM, that the action was viable.

Retirement dreams ruined

The Breadsells were happy to commit at the January sausage sizzle and on Tursday said it was "absolutely fantastic news" the class action had been filed.

They are worried they are stuck with a property tainted by the stigma of PFAS contamination through no fault of their own.

Bullsbrook residents Gary and Karen Breadsell and Colin Butland have all signed up to the class action. ( ABC News: Hugh Sando )

Like many Bullsbrook residents, they had never heard of PFAS contamination until 2016, when Defence began supplying them with bottled water and announced an investigation into whether bores and groundwater had been affected by the chemicals used at Pearce air base.

Mr Breadsell said the news devastated them.

"It burst our bubble, it burst our dream," he said.

They had been excited about retiring to the property, across the road from farmland and with a house they could transform with their renovation skills.

But last month, the couple took the property off the market because they were unable to sell it, even though official testing had shown their bore water to be safe to drink.

Like other people living on the western side of Bullsbrook, they have no scheme water.

'Financially, we're stuffed'

The lead applicant for the class action, Reannan Haswell, still gets bottled water delivered fortnightly because her bore water was not safe to drink.

She and her family moved to the area in 2010.

"PFAS has impacted us pretty hard," she said.

"We had plans for this house. We had it on the market not long before the contamination inquiry started in this area.

"And once we realised the inquiry was going on, we realised potentially we couldn't sell because we could be sitting on a contaminated property."

PFAS class action client Reannan Haswell, second from left, with her partner, their three children and American activist Erin Brockovich, right. ( Supplied )

Ms Haswell said they had taken a big financial hit because of the contamination.

"Financially, we're stuffed, we really are," she said.

"We can't sell our property, we can't move on, so we're stuck here."

Mr Breadsell estimated their loss in property value was between $100,000 and $200,000.

The keen renovators said they had spent up to $180,000 fixing up the property, including installing a new septic system and spending $18,000 on bore water filtration systems.

To add insult to injury, the economic aftershocks of coronavirus restrictions forced the couple to shut down their property management business last month

But they are grateful to have picked up fly-in, fly-out work at a Pilbara mine site, helping to sanitise workers' spaces against another contaminant — the coronavirus.