Environment Minister Phil Hogan has announced a grant scheme of up to €4,000 for households whose septic tanks require upgrading.
Inspections will begin in the new year. Properties whose waste treatment systems have registered and fail the inspection will be eligible for a grant.
Homeowners will have to register their septic tanks by February 1 in order to qualify for a grant. Inspections are being carried out on unregistered properties also.
To date, 290,000 people, or 58% of those with septic tanks, have registered their systems.