PORTLAND — Portland Water District trustees recently approved a $47.8 million budget for 2010 that includes a more than 3 percent mid-year rate hike.

The $37.2 million operating portion is essentially the same funding as the current budget, spokeswoman Michelle Clements said in a press release.

Included in the budget is a $10.6 million capital improvement program, which will fund several infrastructure projects. About $4 million will be used to upgrade aging waste-water treatment facilities and $3.5 million will be put towards water distribution renewals.

The budget assumes a 3.5 percent, mid-year water rate increase, estimated to add about 50 cents to a typical residential water bill. Trustees are expected to finalize the actual water rate increase, which will not affect waste-water rates, in the coming months.

The PWD is a quasi-municipal group that provides water, waste-water and environmental services to 10 greater Portland communities, including Portland, Cape Elizabeth, Cumberland, Falmouth, Scarborough and South Portland.