Who Should We Hold Accountable for Basement Flood from Water Filter Burst?

Three days ago, we found a leak in our water softener and called a Coolray plumber. He said our Pressure Reducing Valve (PRV) was old and causing high water pressure, so we paid $550 to replace it. He checked the water filter and said it was fine.

Two days later, our basement flooded because the water filter burst. The plumber claimed the water pressure was normal and the burst was due to internal distress. They called a remediation company, and we confirmed our home insurance covers this.

We're unsure who to hold accountable. Should we go after the water filter company, even though we might not get much compensation? Or should we tell our home insurance that the PRV caused the damage, although this might affect our home history and future sales?

**Advice needed!**