You will have to pay a fee of €20 if you request a re-inspection after receiving an Advisory Notice.
Water Services Act 2007 (Re-inspection) Regulations 2013
http://www.environ.ie/en/Legislation/Environment/Water/FileDownLoad,33444,en.pdf
In a new build the householder has 90 days after connection of the system in which to register the system at a fee of €50. This does not apply to a previously registered system which has been replaced or upgraded.
Domestic Waste Water Treatment Systems (Registration) (Amendment) Regulations 2013
http://www.environ.ie/en/Legislation/Environment/Water/FileDownLoad,33419,en.pdf