That's because Massachusetts is among the minority of U.S. states that don't require home sellers to disclose flood damage or risk to potential purchasers.
An Act enhancing homebuyer awareness by providing notice to persons purchasing property in a flood zone (H. 1345 | S. 753) – filed by Rep. Thomas Walsh and Sen. Dylan Fernandes – would remedy this. The bill requires sellers, prior to accepting purchase offers, to disclose the extent of any previous flood damage and whether the premises are located in flood hazard areas.
This bill needs support from as many legislators as possible to gain momentum at the State House, so ask your legislator to cosponsor H. 1345 / S. 753.