Local councils lacked funds and expertise to run system
Irish Water's investment plan notes a number of major issues which prevented local authorities from running the network effectively.
They included a lack of funding from central government and not being allocated the technical resources needed.
Among the issues noted were:
Annual spend on maintenance should have been €200m-€250m, but since 2008 actual spending was a "fraction" of this figure.
Local authorities did not have the resources to operate high-tech plants. This resulted in operations being outsourced to the private sector for up to 20 years, at an annual cost of €120m.
Some new plants are over-sized, and consideration was not always given to upgrading existing assets.
A total of €130m was spent installing leak detection equipment, but there was no funding to operate it. This resulted in leak reduction targets being missed, and only 50pc of the so-called district meter areas were operable in 2014.
Some plants were built to link households with septic tanks to the public sewer systems, but without a commitment to connect. A number are "heavily under-utilised" as a result.
Improvement works were not always sufficient or suitable.
"Poor quality" infrastructure was installed by some developers and group water schemes, which has the potential to result in a "major financial liability".