Household water bills in Scotland face an average rise of £9 per year, above inflation, over the next six years.
The industry regulator has published its draft plan for allowing Scottish Water to invest £4.5bn up to 2027, £1bn more than the last six-year period.
The investment is expected to help ensure water pipes and sewerage works can withstand extreme weather.
It is also to put the government-owned water company on course for net-zero carbon emissions 20 years from now.
The recommendation of the Water Industry Commission for Scotland (Wics), that bills rise at 2% per year above inflation, is out for consultation.
Alan Sutherland, Wics chief executive, said the plans would "future-proof" services for future generations.
"To delay increased investment would put water quality, reliability and the 2040 net-zero target at significant risk, with the likelihood of even higher bills to fix those problems in future," he added.