The company stated that it is continuing to monitor its raw water intake from all of its sources on a daily basis to ensure it meets "strict quality standards".
Contacting the Chief Executive of NI Water, DUP MP Ian Paisley said: "My office has been called by residents in the Portglenone area regarding the cleanliness of drinking water. Recently the River Bann was affected by blue green algae. However, today I have received calls about drinking water in the area being unclean and undrinkable from businesses and residents.
-- Advertisement --
"I have made immediate contact with the Chief Executive of NI Water and asked that they immediately investigate this and confirm the safety and cleanliness of drinking water supply. If necessary they should provide emergency drinking and washing supply to the area."
In a statement NI Water said: "Drinking water that comes from the water treatment works which use Lough Neagh as their raw water source is designed specifically for the potential of algae to be present. Therefore there are robust treatment processes in place.
"Although increased levels of algae in the tap water can alter the taste and the smell of the water, it does not pose a risk to health."
The utility company also reminded customers that they may notice a difference in their drinking water, however tap water can still be used in the normal way.
