Northern Ireland Water has warned supplies may be cut as the water network faces high demand due to current hot weather and people holidaying at home.
The company has called for the public "to reduce their water usage immediately".
Director of Customer Operations Des Nevin said: “If demand continues at this level it will lead to failures in our network and some customers will lose supply or suffer low pressure. A number of customers over the past few days are already experiencing this, especially those on high ground.
“Yesterday we put 695 million litres of water into our distribution system, this is over 120 million litres more than normal.
“We are asking our customers to help us, especially over the next few days when temperatures continue to be high."
Mr Nevin said there has been increased water usage recently with garden sprinklers and hoses left on overnight.
“A hose uses more water in one hour than the average family uses in a whole day, “ he said.
"A pressure washer can also be a massive drain, so please think about whether the task is really essential at the moment.
“While it is tempting, please avoid using swimming or paddling pools this weekend. Filling a 12ft swimming pool uses the same amount of water 500 people use for daily handwashing.
“We want everyone to enjoy their home and garden, we just need people to think about how they use their water and if what they are doing is essential.”
NI Water has also asked customers to sign up to its free text alert service which keeps people informed about any changes to the water supply.
To sign up visit niwater.com/register-for-keeping-you-informed.
