How far must a septic tank be from a house in Ireland?

The EPA's Code of Practice for Domestic Wastewater Treatment Systems (population equivalent of 10 or less) specifies a minimum horizontal separation distance of 7 metres between a septic tank or treatment unit and any building, including the house it serves. This distance protects foundations from potential settlement or leakage and keeps the tank close enough to the house for practical drainage runs while leaving clear access for a desludging tanker.

The percolation area — the trenches or bed where the treated effluent disperses into the soil — is generally required to be sited slightly further from the house again, and it must also be kept clear of underground services, tree roots and any structure with foundations that could be affected by the wetted soil.

These distances are minimums, not targets, and the code should be read alongside the other setbacks (to boundaries, wells and watercourses) so that all requirements are satisfied simultaneously on the chosen layout, not just the house distance in isolation.