Irish Water has confirmed a possible breach of data protection may have occurred after it sent information packs with the wrong names to over 6,000 customers.
The water company said it occurred with packs sent to the owners of multiple properties.
The company has contacted the customers involved.
They also alerted the Data Protection Commissioner in relation to the incident, once they became aware of it on 4 September.
In a statement Irish Water said: "Our understanding is that the issuing of the letters does not constitute a breach and that the Office of the DPC are satisfied with how Irish Water have dealt with the issue".
Information being collected includes the PPS numbers of customers, how many people live in a a particular property, and whether the home is rented or owner occupied.
The company said in relation to the letters: "Irish Water has apologised for any confusion and concern that this might have caused affected customers".