The average household in Wales and England will see bills go up by 31, the biggest increase in nearly 20 years.
One in five households are finding it hard to pay, as a result of the Consumer Council for Water CCW warning that the rise would squeeze struggling households.
It said customers who can't afford their bill will not be allowed to slip through the net due to a postcode lottery of regional variations in billing.
Water companies must go the extra mile in helping people who need help with their bills, according to Ofwat.
She encouraged customers to ask to be put on a water meter, saying it could bring savings.
She said it's important for companies to help us when we miss a payment to be proactive when they see us going into debt.
Welsh Water's chief financial officer, Mike Davis, said that they had absorbed as much of the costs as possible, but they are not immune to these pressures.
This is a worrying time for some, because of the cost of living pressures, and we want to support as many people as possible, a spokeswoman said.