Re: Water hammer, and arrestors don't work
Water hammer is caused by the inertia of the water in the pipes making the water want to keep moving when a valve (like your washing machine) suddenly shuts. It's kind of like having a concrete Jersey barrier dropped in front of your car when you're tooling down the freeway. The shock will travel back through the pipes and will be absorbed by either pipe expansion or movement.
I'm guessing that the pipes going to the basement shower aren't securely fastened to the building structure past the shutoff valves.
If the static pressure (no faucets open) is greater than 50 PSI, installing a pressure regulator set between 40 and 50 PSI should help. You could also install expansion tanks -- like those used on water heaters -- as a massive shock arrestor on the lines near the washing machine.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.