Workers who are represented by two unions have overwhelmingly voted for strike action over a pay dispute.
86% of Scottish Water workers who are members of GMB Scotland back industrial action and 89% of Unite members have also voted for strike action.
Claire Greer, GMB Scotland organiser, said: “The overwhelming support for industrial action and the strength of feeling among staff about the conduct of senior management is no surprise.
“The way the company has allowed this situation to arise and then deteriorate so badly has been inept and needlessly antagonistic.
“It has only created distrust and conflict and now threatens disruption that could, with a good sense and better judgment, have easily been avoided.
“The solution to this could not be clearer. The pay offer must be decoupled from the wider restructuring of grades and salaries.
“We are happy to discuss both, but separately.”
Unite general secretary Sharon Graham, said: “Scottish Water has got nobody to blame but itself for the mess it has created. It has refused to make our 500-strong membership a fair pay offer.
“Instead, the boardroom has found the time to award its new chief executive an eye-watering pay package.
“Unite fully support members in the fight for better jobs, pay and conditions at Scottish Water.”
Stephen Deans, Unite regional coordinating officer, added: “Scottish Water has refused to meaningfully engage with us on pay and over a proposed new grading structure.
“Unite’s membership includes key frontline workers and without them Scotland’s ability to respond to any crisis stemming from waterworks, flooding and sewers is all but non-existent.
“Double standards have gripped the upper echelons of Scottish Water and we will not let this go unopposed.
“Strike action is now inevitable unless Scottish Water make a reasonable pay offer for 2023 which is separate from negotiations on a new pay and grading structure.”
A Scottish Water spokesperson previously said: “We continue to seek negotiations with trade unions over a very fair and reasonable proposal to increase every employee’s pay by at least 8% and modernise our pay structure in a way that our colleagues are demanding.”