Most of 100+ adult residents of Cheeverstown House in south Dublin have no privacy for providing intimate care, because they share bedrooms and use multi-functional bathrooms, according to a report by the Health Information and Quality Authority.
HIQA also found fire evacuation plans at the facility for people with learning disabilities were unworkable in four out of eight of the centres inspected.
Cheeverstown House is a voluntary organisation serving almost 400 people with intellectual disabilities, many of them adults living on its Templeogue campus and in community houses throughout south Dublin.
The eight centres inspected last April by HIQA accommodate 125 people, most of whom are adults, with children receiving respite care in one centre every fortnight.
HIQA found no centre had a person in charge and that Clinical Nurse Managers visited them between every one and four months.
Inadequate staffing levels curtailed residents' activities and outings, while fire evacuation plans were unworkable in four centres.
Multi-occupancy bedrooms and multi-functional bathrooms meant there was no privacy for providing intimate care to residents.
HIQA also found staff members preparing food were unaware of residents' dietary needs and allergies, and had no training in food hygiene.
Infection control measures were "poor" and residents had no bank accounts, meaning their State allowances and pensions were lodged to Cheeverstown House's central account.
Action plans submitted by the management to address shortcomings were rejected by HIQA as insufficient.
In a statement, Cheeverstown House said it "noted the findings" from HIQA and is working with the authority to agree an action plan to "remedy the issues and concerns raised in an agreeable time-frame".
It said it remains committed to providing quality care to people with intellectual disabilities.
Advocacy group Inclusion Ireland has said the HSE must be more proactive in enforcing compliance with statutory regulations by service providers such as Cheeverstown House.
The organisation's chief executive officer, Paddy Connolly, called on Minister for Health Leo Varadkar to ensure there is independent oversight of how findings of HIQA inspections are being implemented by the HSE and other publicly-funded bodies.
Some residents have not left Sligo centre 'for months'
Meanwhile, according to a separate HIQA report some profoundly intellectually-disabled residents of a HSE-run centre in Sligo have not left it for months.
Inspectors were told a day service previously provided to residents in one unit at Cregg House had closed when staff had left and was not replaced.
HIQA said no structured activities were provided to occupy residents since the closure.
The unit concerned provides residential accommodation and support services for six adults with severe to profound intellectual disability and associated mobility issues.
The inspection, on which today's report is based, was pre-announced and was carried out in February.
Cregg House was found to be seriously non-compliant with statutory regulations in a HIQA report last month.
The complex accommodates a total of 108 residents and was taken over by the HSE from an order of nuns following dispute about the adequacy of state funding three years ago.