Galway County Council guidance says to hire a permitted contractor and hold on to desludging receipts for five years. Many tanks are emptied every 12 to 18 months, though tank size, the number of people in the house and the condition of the system decide the real interval.
The usual signs: slow drains, gurgling toilets, a smell outside, soggy ground above the percolation pipes, and water backing up. The contractor confirms the condition of the tank when they arrive.
Know where the lid is and how a tanker reaches it, find the last emptying date and keep the receipt from this visit.
The CSO 2022 census table puts 45,482 Galway County households on septic tanks or other individual treatment systems. Galway County Council describes a grant of 85% up to €12,000 for eligible remedial work after an inspection. Routine emptying is a separate matter, so check the terms with the council.