The Hannibal Board of Public Works is apparently being sued by its biggest water customer over a recent rate hike.

At its meeting Wednesday, the BPW board went into closed session to discuss a lawsuit being brought by the Ralls County Public Water Supply District Number One.

At issue is whether BPW’s contract gives it the right to raise the rates it charges to the PWSD.

The BPW board voted unanimously last August to raise the rate of all water for resale from $3.94 to $4.75 per thousand gallons, which is the same rate Hannibal water customers pay.

The rate took effect in November, and since then, PWSD has recalculated its bill at the old rate and paid BPW a reduced amount.