Donegal has the lowest number of septic tank registration fees.
The latest figures on the payment of the septic tank registration fee show a huge variation around the State, with only 26 per cent of Donegal tank owners paid-up compared with 81 per cent of Kerry residents.
According to the Local Government Management Agency, some 258,875 properties had been registered up to last week.
A further 20,000 forms were awaiting processing.
According to last year’s census, there are 497,281 septic tanks and other on-site waste-water treatment systems in the State. Including the payments awaiting processing, this represents a compliance rate of 56 per cent.