Todd Saunders lives in a supported residential facility (SRF). It's his home, and his welcome is warm and generous.

"Thank you for coming, it's really good to have you in my home ... you are welcome here," Mr Saunders said.

The sense of security is a stark contrast to the upheaval and uncertainty that led the 52-year-old to need an SRF in the first place.

"I'd been married twice," he said.

"I started to get a bit ill. I had a few problems and it just kept going, getting worse ... so without this place I don't think I'd possibly even be here.

"I can't manage living on my own."

The home provides Mr Saunders' meals, manages his medical care, utility bills, laundry and so on.

It does the same for the 46 other people, men and women, of varying ages who also live there.

Without us people would be in hospital, on the streets

The home is in the Adelaide beachside suburb of Semaphore, and is run by Shane Heffernan and his partner.

Mr Heffernan says residents have varying backstories: life in the corporate world, lawyers, interior decorators, but all share a common thread.

"The majority of our clientele have been assessed multiple times being unable to live independently," Mr Heffernan said.

"So places like Anglicare and Western Mental Health have made that decision.

"If our sector wasn't here these people would be more than likely in the hospital system or on the streets."

Shane Heffernan and Kris Moroney are concerned about the future of the housing due to the changes. ( ABC News: Simon Royal )

As head of the community visitors scheme, it's Maurice Corcoran's role to see conditions in SRF's are up to scratch.

He says some operators do a good job creating a home-like environment.

Others do not meet a reasonable standard.

But as a whole, Mr Corcoran says SRFs provide a crucial accommodation option — sometimes the only one — for highly vulnerable people.

"We would be far worse off [without SRFs] for many of these individuals," Mr Corcoran said.

"They would just have nowhere else to go. They don't have family, they don't have resources, they don't have the ability to rent a home of their own."

But there's a risk to the future viability of SRFs, which both Mr Corcoran and SRF operators believe stems from confusion over the National Disability Insurance Scheme (NDIS) and the SA Government's funding commitments.

Subsidy clarity needed

Currently the state pays homes a subsidy for each resident of between $7.25 to a maximum of $14.65 per day.

The president of the supported residential facilities association, Kris Moroney, says it's the future of that subsidy that's causing most of the grief.

"We've had no clarity around that," Ms Moroney said.

"It's been an ongoing conversation with the State Government we are waiting on some more information and we are waiting on an NDIS forum to happen for our sector.

"At this point in time we are 44 days from the commencement of rollout so it's a pretty scary time to not have clarity around some issues that will leave up to 800 people potentially homeless.

"I'm worried we are going to fall between the cracks."

In a statement to the ABC, the NDIS says it will provide some funding for accommodation needs and that "this support is for people with very high needs".

"It was agreed by governments that accommodation outside of the NDIS remains the responsibility of the states and territories," it read.

The SA Government gave its own statement.

"The State Government has guaranteed funding to the supported residential facility sector while it transitions to the NDIS," it read.

"We will continue to fund SRF residents until they get an approved NDIS plan."

But Mr Corcoran points out not everyone will qualify for NDIS, nor is it clear how the State Government would assist those who miss out.

"At one SRF, early interpretations and assessments by the NDIS found that only six out of those 60 residents were going to be initially eligible for those NDIS packages," Mr Corcoran said.

"Many of these SRF owners are up for new leases and leasing new buildings, they just don't have the certainty to make that commitment."

Family-like group being spilt up

Jeanette Scannell is one who has chosen not to risk signing a new five-year lease on her SRF.

Jeanette Scannell has called in a painter to fix up the building before handing it back to the landlord. ( ABC News: Simon Royal )

Instead the painters have come in, done some touch up work before the place is handed back to the landlord.

"We are not prepared to put our house on the line and that's what it comes to," Ms Scannell said.

While Ms Scannell has run the home for 14 years, many of the residents have been there for decades.

"They have been family here for 40 years plus and now they are all separated we've managed to keep nine together, but that's the maximum and the rest are just by themselves and it's the saddest, saddest thing."

Mr Corcoran says the NDIS (and the state) need to remember the founding ethos behind the scheme: to remove the lottery-like nature of who gets decent disability services and to provide people with a disability, choice.

He believes not everyone living in an SRF would choose to stay, but for those who do, that should be supported.

One of those people is Todd Saunders.

"I would say to people trying to fix the system, what are you doing?

"It's not broken, what are you trying to fix ... you are scaring people."