Attorney General William Tong vowed to launch a full investigation into Aquarion Water Company's request for a 27% rate hike.

Eversource, which bought Aquarion in 2017, filed the request with state regulators Friday.

The rate hike would be implemented over three years, and would be the company's first in nearly 10 years.

The company says in that time, it has invested more than $740 million in critical infrastructure.

Tong said in a statement, "The last thing Connecticut families and small businesses need right now is a double-digit water bill hike, on top of steadily mounting surcharges. I fully support modernizing our aging water infrastructure, but we need to make sure we are doing it in a way that respects the financial pressures Connecticut families and small businesses are facing right now."