Sierra Leone and Liberia risk new deadly epidemics akin to the impact of the Ebola virus due to lack of clean water and hygienic conditions in most homes, an NGO warned Tuesday.

WaterAid said the two provisions were the "first line of defence" against infectious diseases but needed to be put into place before outbreaks began.

In Sierra Leone, more than 37 percent of people do not have access to clean water, the British-based group said in a statement. In Liberia, the figure is 24.5 percent.

When it comes to basic sanitation, WaterAid said the figures were even higher -- 86.7 percent of people in Sierra Leone and just over 83 percent in Liberia live without access to it.

"The terrible suffering of the people of Sierra Leone and Liberia during the Ebola crisis is at high risk of being repeated in another disease epidemic if we do not see action to improve water, sanitation and hygiene practices in our communities, schools and healthcare facilities," WaterAid's Joe Lambongang said in the statement.

"These basic provisions are the first line of defence against infectious diseases including Ebola.

"To ask healthcare professionals to battle an epidemic without clean water, safe toilets and somewhere to wash their hands is unrealistic and needlessly puts lives at risk," he added.

In June, Liberia said it was free of Ebola, meaning there were no known cases in west Africa of the tropical virus that left more than 11,300 people dead in the region since late 2013.

The World Health Organization declared an end on June 1 to Ebola cases in Guinea -- where it first broke out in December 2013 -- and in Sierra Leone on March 17.

According Sierra Leone's health ministry figures, 30 percent of the population dies every year of diseases passed on by contaminated water.