The Environmental Protection Agency has reported the lowest ever number of people on boil water notices, following improvements by Irish Water over the past year.
The EPA's Programme Manager has said the number of people on boil water notices has been reduced from 23,000 to 6,000 since this time last year.
Speaking to RTÉ's News at One, David Flynn said he expected that number should drop to virtually nil by the start of next year.
He said the next step will be to address the 112 supplies at risk within the water system.
Mr Flynn said under-investment in the system over decades has caused the majority of the problems.
He added that a Remedial Action List of at risk supplies has been given to Irish Water and they will be dealt with as a priority.
Ireland has 973 public water supplies and over 80% comes from surface sources such as rivers and lakes, which vary greatly in quality.
However, last year the EPA tested more than 236,000 samples of water over the country and found the quality of public drinking water in Ireland is very high.
99.9% of public water samples passed all the EPA's microbiological tests while 99.94% passed all chemical tests.
The EPA has confirmed that four water supplies served by the Stillorgan Reservoir in south Co Dublin supplying 220,000 people, are no longer at risk from contaminants like cryptosporidium following remedial action by Irish Water.