Irish Water is being criticised about meters being installed with numbers that appear to be obscured and not visible to customers.
Its website shows meters with a clear series of numbers, five on a black background, and the last three digits on a red background.
But some customers have complained that they can't see some of the red numbers and find it difficult to monitor usage as a result.
Irish Water said both types of meters it fits comply with required standard but said a low power radio unit which allows meters to be read remotely by a passing Irish Water van - may partially obscure the red digits on one of the meter types.
"Customers should be able to see at least two red digits, which gives the usage in cubic meters to two decimal places or to the nearest 10 litres," said an Irish Water spokesperson.
Units of water are measured in cubic litres, being the first digit from the right on a black background.
A cubic litre is 1,000 litres of water.