34% of domestic septic tanks failed the Environmental Protection Agency inspection in Co. Tipperary last year.
The Premier County is below the national average which is at 53%.
The local authority carried out 62 inspection in 2021.
The data shows that of those that failed the inspection 60% got their septic tanks were fixed by end of last year.
However Co. Tipperary had one of the lowest fix rates in the country – Leitrim and Roscommon were the only counties that had a lower fix rate of 47% and 45% respectively.
The EPA is calling on local authorities to increase enforcement to ensure houseowners fix faulty septic tank systems in a timely manner.