Massachusetts Auditor Suzanne Bump, Democratic State Sen. Jo Comerford of Northampton and Northampton Mayor David Narkewicz have endorsed incumbent Massachusetts Sen. Ed Markey.

The trio of endorsements, announced Sunday afternoon outside Northampton City Hall, come as Markey faces primary challengers U.S. Rep. Joe Kennedy and labor attorney Shannon Liss-Riordan.

The endorsement also followed Saturday’s announcement that influential labor leader Sara Nelson, president of the Association of Flight Attendants union, was backing Markey.

According to a news release from the senator’s office, Northampton, in 2014, became one of a handful of Massachusetts communities to create a stormwater utility to finance overhauls of aging stormwater and flood control systems impacted by climate change. Narkewicz, Markey said, has been a leader in developing green infrastructure to adapt the city for climate change.

The senator’s office noted that an audit conducted by Bump found that only 6 % of Massachusetts municipalities have planed to adapt their water infrastructure for climate change, an issue that Markey has worked to address at the federal level.