FIRMS closed by Covid-19 face the risk of unfairly high water bills based on last year's normal consumption rates, according to Chambers Ireland.
The Covid-19 crisis has exposed the unfairness of imposing a rigid charging system, the umbrella body for chambers of commerce across Ireland has argued in its submission to the Commission for Regulation of Utilities (CRU).
The CRU is seeking public views on its plans - temporarily deferred by the virus crisis - for a nationally standardised system of Irish Water charges on business users. They currently vary widely by local authority.
Chambers Ireland said the CRU's proposed reforms to charges were "extremely strict and inflexible".
It said firms should be given the means to appeal for a quick, simple transition to a lower tariff band based on their own measurement or estimate of current water use.
Chief executive Ian Talbot said: "The CRU's proposals will have businesses paying for their water at rates based on last year's usage.
"With so many businesses closed, this will put many businesses into an inappropriate category. This will force many businesses to challenge the charges, a prospect which could bring the harmonisation process into disrepute."
Mr Talbot said a second wave of bill challenges was likely in 2021 because firms again would be issued with bills likely to be "completely unrepresentative" of actual consumption levels.
Other CRU plans "to transfer all the risk associated with on-site water leakages onto the business customers of Irish Water" were particularly unreasonable given Covid-19 restrictions on premises, Mr Talbot said.
"Many businesses are not free to maintain, or perhaps even access, their business premises. Key workers may be cocooned. The proposed system is so inflexible that it cannot deal with real-world problems."