A hosepipe ban is now in force across Northern Ireland as temperatures soar.
It was put in place by NI Water from 6pm on Friday, amid efforts to stop any interruptions to supply.
The hot weather is expected to last with the sun set to shine into the weekend across most of the UK, as water companies said usage had been "significantly more" than normal.
NI Water Chief Executive Sara Venning said the company was appealing to customers to stop non-essential use, as hoses and sprinklers were causing strain on supplies.
She said: "In recent days our treatment works have been operating at near maximum levels with over 700 million litres of water being put into the network, which is some 25% more than is normal for this time of the year.
Despite these steps, demand continues to outstrip supply
She added: "It would be our intention to introduce a formal hose pipe ban in an effort to protect the public against the increased threat of supply interruptions."
The ban prohibits watering private gardens; or washing private motorcars and the company have said that its introduction will take effect from the weekend.
Huge spikes in demand for water at mornings and evening peak times mean utility companies are having to pump millions more litres of water into the system, but they say it is often being used by customers as fast as it is supplied.
Customers in some areas including parts of Belfast and Armagh as well as other rural hand high lying areas have already experienced loss of pressure and intermittent supply failures.
Water-saving tips include:
Turn off the tap when brushing your teeth
Take shorter showers
Take a shower instead of a bath
Use a bowl for washing vegetables
Fill the kettle with only as much water as you need
Avoid washing cars and vans during this time