NI Water has encouraged the public to continue to use their water supply wisely despite the drop in temperatures.
A number of properties across Co Antrim, Co Down, Co Londonderry and Co Tyrone suffered water supply issues last week as the heatwave reached its peak.
NI Water warned a hosepipe ban was possible due to the extreme demand in the system.
On Thursday, NI Water, the Department for Infrastructure (DfI) and the Department of Agriculture, Environment and Rural Affairs (DAERA) thanked the public for their actions to reduce demand on the water supply system.
Water reserves “may have improved slightly” but NI Water, DfI and DAERA, encouraged everyone not to become complacent in a united message.
NI Water said it moved a 38.5 million litres of water by tanker across Northern Ireland since the high demand incident began on July 16.
Thirty-six tankers carried 1,800 loads of treated water to reservoirs which were struggling to cope with customer demand.
The operation involved staff from across the business making sure the tankers continued to operate 24/7.
Infrastructure Minister Nichola Mallon said the operation was one of the largest movements of water across the network by tanker that NI Water has ever carried out.
“It is a complex process with every tanker cleaned and sterilised as well as ensuring staff availability throughout the night to drive and fill the tankers,” she stated.
“Scientific teams are also on hand sampling the water to ensure it continues to meet stringent quality control checks.”
Agriculture Minister Edwin Poots added: “Some rain is here, but it has still been a dry summer, which puts pressure on our water sources, which are essential for farmers, small businesses and local councils.
“Our bodies of water, including rivers and lakes, have taken a major hit to their levels and we must still be vigilant in how we use water so they can recover.”
NI Water’s Director of Customer Operations, Des Nevin, said the recent rainfall is welcome but the company does not anticipate that it will have the necessary impact on the reservoirs.
“We continuously monitor raw water storage in our reservoirs but storage levels vary and depend on a number of factors,” explained Mr Nevin.
“For example, rain needs to fall in the right areas - less than half of the land surface area of Northern Ireland acts as raw water catchment for reservoirs.
“Soil moisture levels are at a record low - the prolonged spell of hot, dry weather has led to record low soil moisture levels.
“Where rain falls on very dry soil it rehydrates the soil first and will only flow into reservoirs once the soil is sufficiently hydrated.
“We are seeing a situation where the demand on water supply has reduced over recent days and we would thank those customers who have helped us by using water wisely during this period and I would appeal to all our customers to continue to think about how they are using water at all times.”