Maine Water Co. announced Monday it will invest $3 million to update the aging drinking water infrastructure in northern York County.

The company will make investments in the company’s distribution center, in its water treatment plant and in a critical pump station in the Biddeford-Saco area, said Maine Water President Judy Wallingford. She anticipates the company will soon request permission for a rate increase that could add as much as $5 a month to the water bill of an average customer in the Biddeford-Saco area.

“Northern York County is poised for solid economic growth in the next few years and it’s our job to make sure the water infrastructure is dependable well into the next few decades,” Wallingford said.

Wallingford said a recent study of Maine Water’s infrastructure in the Biddeford and Saco water system showed projects in Biddeford and Old Orchard Beach were the highest priority for the company. The water system in that area serves customers in Biddeford, Saco, Old Orchard Beach and the Pine Point section of Scarborough and last year received $2 million in improvements.

Wallingford said the company will soon submit an application to the Maine Public Utilities Commission requesting a rate increase, an approval process that could take as long as nine months.

While the exact amount of the rate request has yet to be determined, Wallingford anticipates it could add $4 to $5 to customers’ monthly water bills.

Customers in the Biddeford and Saco area currently pay an average of 40 cents per day for water, compared with the average of $1 per day for water for most Mainers, Wallingford said. Maine Water customers will be notified when the company requests a rate increase.

The $3 million in improvements announced Monday will include a project to replace an existing 8-inch water main that dates to the early 1900s with a 12-inch water main on West Street in Biddeford. The $1.2 million upgrade will be done in conjunction with a Maine Department of Transportation road project in the street. Replacing the water main will improve water flow for fire protection to Hills Beach, the University of New England and along several other roads in coastal Biddeford, according to the company.

Also scheduled are distribution system upgrades for Colby and Winona streets in Old Orchard Beach. The chemical handling process will be upgraded at the water treatment station on South Street in Biddeford. Maine Water plans to upgrade a pump station in Biddeford that serves a high service area in the southwestern part of the city in the area of Route 111. The location of the pump station has yet to be determined, but company officials estimate it will cost about $850,000.