Irish Water received over 180 complaints from customers in the Shannonside region last year.
Details released through freedom of information show the largest volume of complaints was from Roscommon customers - where 29 issues of concern were classified as general, 28 were linked to billing issues and 20 were marked as operational.
53 complaints were made in County Leitrim - the majority linked to operational issues.
A total of 45 complaints were made in County Longford - including one emergency complaint and one linked to payment as well as credit and collections.