Manx Utilities are seeking a company to survey the Islands reservoirs.
It's looking for an organisation to carry out calculations and sediment profiling at the active sites at Sulby, West Baldwin, Kerrowdhoo and Clypse, along with other locations at Cringle, Ballure and Block Eary.
In its tender Manx Utilities says it's important to gain a better understanding of the size, shape and volume of its assets in this case.
Interested parties who have questions or clarification to seek should put their requests to the government portal by Noon on March 14 - with the deadline for submissions the following week on March 21.