Elphin has a population of around 70 residents and has until now received drinking water from a basic treatment works which uses a spring at Knockan Crag.
Scottish Water’s communities manager for the Highlands Joanna Peebles said the improvements will enable the people of Elphin and visitors to benefit from a higher quality of drinking water.
"The Ullapool supply has been upgraded and is fed from high quality boreholes at Inverbroom, with water receiving modern filtration," Peebles said.
Scottish Water will connect Elphin to the Ullapool supply through a new 10km pipeline, and the new supply is expected to commece in June 2012.
The company constructed a pumping station at Drumrunie and another one at Strathcanaird where the Ullapool supply currently ends, and it also installed a storage tank at Elphin.
