Submitted by jng2013 t3_10fbfwr in massachusetts
I bought a dishwasher from Costco.com and they sent out a plumber to install it for us. Plumber said code required a "water hammer arrestor", which was an air chamber to reduce the water hammer effect when a water valve closes, and it was $140 to install it. With the dishwasher already delivered and old one removed, I felt I had no choice but to pay. Is this device actually required by code for a dishwasher? I did a google search and couldn't find a definitive answer for Boston. Just wanted to make sure I wasn't completely lied to.
individual_328 t1_j4vxdh3 wrote
Here's the MA plumbing code. Water hammer requirement is on page 72.
https://www.mass.gov/regulations/248-CMR-1000-uniform-state-plumbing-code