Customer complaints about Irish Water fell by nearly 20% last year, according to the independent energy regulator.

The Commission for Energy Regulation (CER) dealt with 650 issues raised by Irish Water customers in 2015.

But the body has said that the higher volume of issues in 2014 may be due to the introduction of water charges that year.

The CER dealt with almost 4,000 complaints in 2015 - from gas, water and electricity customers.

The largest number of complaints were about Bord Gáis Energy. 

The company has a 23% share of the gas and electricity market, but made up over 40% of complaints.

Electric Ireland, which has a 50% market share, contributed to 37% of objections. 

SSE Airtricity, with a 15% share, accounted for around 13% of complaints.

The CER received a total of 3,884 contacts from consumers.

The majority of complaints investigated related to issues with inaccurate billing, incorrect account details, problems with budget plans, and large catch up bills following estimated readings.

Across all of the electricity, gas and water sectors, 53% of complaints were either upheld in favour of the customer or the customer accepted a settlement offer.