The Shannonside region has 6.5% of domestic wastewater treatment systems in Ireland.
That's according to figures from the Central Statistics Office, where almost half a million waste-water treatment systems were registered.
Septic tanks are used in these systems to collect wastewater without connecting it to a sewer.
While, public authorities are connections to the public sewer system.
In 2022, with 15,472 registered domestic wastewater treatment systems, Roscommon had the highest local proportion of systems at 3.2% followed by Leitrim with 1.7% and Longford with 1.6%.
Public authorities accounted for 1.5% and other non-domestic owners accounted for the remaining 1.4%.
In Longford, public authorities accounted for 4% of all owners in 2022, one of the highest nationally, whereas in Roscommon it accounted for 1% and Leitrim with 3%.
Kildare had one of the lowest public authorities with 0.1%.
Household owners accounted for 97% of all registered wastewater treatment systems in 2022.
Government legislation requires all households with domestic wastewater treatment systems to register them.
