The public is facing a growing "care injustice" as people are finding it more difficult to get help in England, the regulator is warning.
The Care Quality Commission highlighted growing hospital waiting lists, delays at A&E and record dissatisfaction levels with GPs in its annual report.
Mental health and old-age care were also becoming harder to access.
And the report said even where there was care available many people only had the choice of failing services.
In its 130-page review, the regulator pointed to
- the lack of out-of-hours GP care
- rising rates of preventable admissions to hospitals
- overcrowding on wards and worsening A&E waiting times
- the growing waiting list for routine operations
- mental health patients being made to travel long distances for treatment
- older people going without the help they need for daily tasks such as washing and dressing
Don Redding, of the patient group, National Voices, said it was clear the system was "malfunctioning" and the report should act as a "loud alarm bell".
He urged the government and NHS leaders to take notice as they prepare to publish their 10-year NHS plan later in the autumn, setting out how the extra funding for the health service will be spent in the coming years.
The report is being published as the BBC relaunches its NHS Tracker project, which enables users to find out how their local areas are performing on cancer, A&E, hospital care and mental health services.
Which places are struggling the most?
The CQC is particularly worried about four areas of the country where access to good hospital and social care is problematic.
These have been named as the Isle of Wight, Kent, Wirral and Portsmouth.
People in these areas are hit by both struggling hospitals and poorer-than-average care services, with inspectors worried things are going to get better in the future.
In Kent there are seven local hospitals that are all judged to be not good enough, while one in three nursing homes is failing.
The Isle of Wight's only hospital has an inadequate rating and a third of care homes are failing.
In Wirral, half the nursing homes are judged not good enough along with the two local hospitals, while nearly half of home care services in Portsmouth and its main hospital are not up to scratch.
Does this mean services are getting worse?
No. Overall, the CQC said the majority of services were rated as good or outstanding and the quality of care was being maintained.
In fact, on each measure, there has been a small increase in the number of good and outstanding performers on the year before.
However, that should not be interpreted as a definitive sign of improvement.
The CQC prioritises the worst-performing services for reinspection which means the overall picture is more likely to improve than deteriorate, because the poorest performers cannot get a lower rating.
Instead, the problem being highlighted is more a matter of it getting harder to access services.
People are waiting longer for treatment, going without or – in the case of mental health care – sometimes having to travel long distances for treatment.
What has gone wrong?
It is a simple matter of supply and demand. The ageing population and rise in illnesses such as diabetes means more and more people need care.
While the NHS budget has been rising, it has not been enough to keep up with the growing numbers of people needing treatment.
There are shortages of staff in key areas – 12% of nurse posts and 9% of doctor posts are vacant.
But the CQC is also clear there is a structural problem.
The nature of illness, which means people rely on ongoing care for incurable conditions like dementia, is placing a greater reliance on the way the NHS works with care services, such as nursing homes and help in the home for tasks such as washing and dressing.
Care services are organised by councils or rely on people paying for it privately.
It has created a situation where growing numbers are simply going without help in their later years.
The CQC pointed to figures showing the numbers not receiving the care they need has increased nearly a fifth in two years to 1.4 million – that is nearly one in seven older people.
Caroline Abrahams, of Age UK, said it has got so bad that it has become "pot luck" whether you can get help.
What is being done about this?
The Department of Health and Social Care said action is being taken.
It pointed to the increased funding for the NHS that was announced by the prime minister in the summer.
That will mean by 2023 the budget will have risen by more than £20bn a year in real terms.
There is also a big emphasis being placed on the NHS to work closely with care services.
On top of this, ministers have promised to reform the funding system for social care, with a Green Paper expected to be published later this year.
A spokesman added: "We want the NHS to be the safest healthcare system in the world – and this starts by ensuring every single patient in this country receives the highest quality of care, no matter where they live."