Customer complaints about Irish Water fell by nearly 20 per cent last year, according to the Commission for Energy Regulation.

The commission dealt with 650 issues raised by Irish Water customers in 2015.

But the body thinks the higher volume of issues in 2014 may have been due to the introduction of water charges that year.

The CER dealt with almost 4 thousand complaints in 2015 - from gas, water and electricity customers.

The largest number of complaints were about Bord Gais Energy.

The company has a 23 per cent share of the gas and electricity market, but accounted for over 40 per cent of complaints.

Three quarters of complaints about energy suppliers related to problems with bills.