Ofwat said offering help should be a priority for all water firms.
It stressed that different parts of the UK will see variations in their bills – for some, the amount they pay for water will increase by 10% while for others will reduce by 6%.
That comes at a time when water companies issue customers’ bills for next year, showing an average increase of 1.7% or about £7, the regulator said.
David Black, Ofwat interim Chief Executive, said: “Many households are worried about their bills, and we expect water companies to play their part in supporting customers.
“Our research shows that only 15% of customers know about the financial help available to them and just 3% are actually getting financial support from their water company.
“Those who are struggling need to know that there is help available.”