Three unions are prepared to ballot 1200 members of 1600 workers at Northumbrian Water and Essex and Suffolk Water over proposals to axe the company's final salary scheme.
The ballot for members of GMB, Unite and Unison will commence on 18 September after notice is served on 11 September.
Northumbrian Water has been in consultation with workers over plans to change its final salary scheme to a career average scheme since January this year.
GMB organiser Maxine Bartholomew told PP the union was "ready to press the red button" on the ballot on Friday.
She added: "Throughout eight months of consultation, Northumbrian Water has consistently failed to demonstrate the existing defined benefit pension scheme is unaffordable. Northumbrian Water remains a highly profitable company which generated an operating profit of £384.3mn for the 15-month period ending March 2015."
The company said the final salary scheme was unsustainable. It will contribute 19.5% and members will add 8% to the new Career Average Revalued Earnings (CARE) scheme.
The GMB said a formal ballot for industrial action would take place after consultation has concluded on 10 September.
Earlier this year a strike by Tata Steel workers was called off after the firm agreed to keep its final salary scheme open in exchange for cost-cutting measures while a dispute at Nestle is continuing.
