The state Department of Public Health announced Thursday that $40 million in low-interest loans to protect the state’s public drinking water by financing local projects aimed at improving water treatment plants and other facilities was approved by the State Bond Commission on May 27.

Among projects that will receive funding are a Groton Utilities water treatment upgrade project and upgrades to Norwich Public Utilities’ water treatment plant and distribution system.

The package approved by the Bond Commission will make it possible for the state’s Drinking Water Fund to provide low-interest loans to local and regional public water systems for drinking water improvement projects, the health department said in a news release.

Under this program, loans are repaid at approximately half the market interest rate over 20 years.

Groton will receive an additional $8 million, for a total funding of $42 million, for a major upgrade of its surface water treatment plant.

Groton will make significant improvements to its plant to improve water quality, modernize treatment technologies and upgrade aged facilities.

The plant originally was constructed in 1938, and improvements to the facility are crucial for long-term infrastructure sustainability, the health department said.

Norwich Public Utilities will receive $13.5 million for water treatment plant filtration upgrades, finished water transmission main improvements, and construction of a new water storage tank to improve water quality, the health department said.