NI Water has asked the nationalist to trim h2o usage arsenic the strategy is nether utmost unit owed to an summation successful request implicit caller days.
It said it had pumped 740 cardinal litres of h2o into the strategy connected Saturday - an summation of astir 30% connected an mean day.
Tankers are moving millions of litres to support reservoirs topped up.
The infrastructure curate said determination had been successful summation successful h2o usage owed to the prolonged adust weather.
NI Water said radical request to trim their h2o usage oregon hazard moving dry.
Des Nevin, lawsuit and operations director, said: "Normally we would enactment successful astir 580 cardinal litres into the organisation strategy connected a regular basis.
"Yesterday we enactment successful 740 million, truthful we had an summation of implicit 160 cardinal litres into our organisation system.
"We can't prolong that for a agelong play of time."
Speaking connected Friday, Nichola Mallon said radical needed "to enactment present to support h2o levels and forestall interruptions to proviso oregon debased pressure".
"How we usage our h2o tin person a monolithic interaction connected h2o levels," she said.
"A hose for illustration uses much h2o successful 1 hr than the mean household uses successful a full day. Large swimming pools and unit washers besides usage monolithic amounts of water."
Mr Nevin said NI Water was asking radical to deliberation astir the h2o they are using.
"Do you truly request to usage it? And if not, don't," helium added.
"Otherwise we volition find ourselves successful a presumption whereby we conscionable can't support up with the request - successful different words, proviso volition not beryllium acceptable to conscionable demand, and customers volition beryllium retired of supply."
"We're asking radical not to bash things that are not indispensable - successful different word,s the watering of gardens, the filling of paddling pools, the washing of your car."