Business customers could be refunded if their water supplier was to exit the market.
Under new rules, approved by Ofwat water retailers will need to return credit balances to customers at the end of their contract.
That follows a consultation launched by the water services regulation authority to change the Customer Protection Code of Practice (CPCoP).
The proposed amendments to the CPCoP aim to deliver protections for those business customers who have accrued credit against their accounts.
Last month, Ofwat unveiled measures to raise credit quality and transparency standards for water firms in a bid to protect customers against potential company financing risks.