Healthwatch said on average people wait two months between contacting their local authority and actually being able to access services, a period of time which could cause “incredible stress.”
While councils have a duty to support carers, the research found gaps in the data, with a third of councils unable to provide a recent idea of how many carers lived in their area and nearly half unable to say how long carers on lists had been waiting.
Healthwatch said better data is urgently needed if local authorities are going to reach out to carers earlier and make a successful case for resources to meet local demand.
According to the charity Carers UK, unpaid carers currently contribute Â£132 billion pounds worth of care support to family and friends. This is more than seven times the Â£17 billion councils spend annually.
It is estimated it would take four million extra full-time paid social care staff to cover the work of unpaid family carers.
Healthwatch said its report was derived from 5,447 carers across England, many of whom only found out about the help on offer by chance or at a point when they had already started struggling.
It often meant the person cared for suffers, sometimes ending up in hospital or a residential care home, affecting their quality of life and ultimately costing the NHS and social care sector more money.
Carers themselves sometimes had to give up work or became ill themselves. The emotional toll of being a carer - in particular feeling guilty about not being able to cope - can also leave lasting scars.
Healthwatch England national director Imelda Redmond said carers “kept the NHS and social care afloat.” But as society ages “services need to be much more on the front foot.”
She said the Government’s green paper on social care, which is expected later in the autumn, provides a “brilliant opportunity” to recognise their contribution and make plans to ensure they get the support they need.
Glen Garrod, president of the Association of Directors of Adult Social Services, also called for the green paper - together with long-term funding solution for social care.
He said it was “deeply regrettable that adult social care directors find themselves facing difficult choices, against a backdrop of insufficient funds to support carers in their area to the extent they would like to be able.”