Over the six year regulatory period, Scottish Water can only increase typical household bills by £5 or less each year.
The water company will be permitted to increase its wholesale charges at no more than the Consumer Prices Index (CPI) – 0.3 per cent per year.
WICS chief executive Alan Sutherland said: “ will allow Scottish Water to build on what it has achieved over the past five years while ensuring that customers receive value for money and the further improvements in service they want.
“Price increases that are capped at less than the level of inflation over the period will provide certainty in difficult economic times while ensuring that Scottish Water has the resources to deliver the objectives set by the Scottish ministers for the industry.”
The review process saw the introduction of a number of regulatory innovations, including the “extensive involvement” of the Customer Forum, which represented the interests of consumers throughout the process.
Sutherland added: “We believe that this approach has led to a better deal for customers.”
The final determination also gives priority to: external sewer flooding; visible leakage; reduction in carbon emissions; managing responses to extreme weather events; and minimising escalated or upheld complaints to the Scottish Public Services Ombudsman.
Scottish Water is also expected to improve its service performance over the regulatory period so that it: maintains its overall performance assessment score within a target range of 380 to 400 points throughout the period; ranks among the leading UK water companies on the new customer experience measure to be introduced by March 2015; and is among the leading UK utilities for customer satisfaction.
A Scottish Water spokesman said: “This is consistent with the agreement we reached with customers represented by the Customer Forum.
“It will provide our customers with continued stability in water charges from 2015 to 2021, while enabling Scottish Water to maintain investment in its network to build on customer service improvements in recent years and support the Scottish economy.”