Does soundproofing the bathroom walls really work?

Depends on how loud they sing in the shower.

The noise associated with water pipes is caused by excessive flow velocity from improperly sized pipes. If the pipes are properly sized based upon the fixture unit load value, even insulation should not be required.

It's not just the water in the pipes, but the sound of the water spray in general, too. If you're a light sleeper and trying to sleep in an adjacent room, those sounds can seem quite loud and can make it difficult to remain, or get back to sleep.

We will be reconfiguring our bathroom space, and will end up with the bathtub in the bathroom adj to our bedroom right up against the bedroom wall, so are interested in reading about soundproofing options as well.

Depends on what sound you are trying to deaden - & to what degree you would like to "deaden" -

- One of the most difficult sounds to deaden is foot fall
- easier would be the shower singer

In sound studios they use multiple layers of sheetrock of differing thickness and staggered seams - along w/lots of other materials (this may not be an option for you - unless all trim is being removed during remodel)

In a bathroom - re: water in pipe sounds - Old black iron pipe is far superior than the newer PVC pipe for deadening sounds sloushing through plumbing

Totally deadening all sounds is unlikely, very costly, and difficult to achieve in a typical home/master bath - too many obstacles that actually help transfer sound rather than deaden - best scenario is to plan soundproofing before building - In your case if you are doing a total gut you can get some good soundproofing built into plans -

- doors, windows, wallbaord adhered directly to joists/studs (**esp 1/2" which is what builders use), electrical boxes, hardwired lighting/fans, ductwork are all conduits to sound

- If it's just sink wall that you would like to deaden the sound - using iron pipe wrapped w/special insulation (NO GAPS!) and using Roxul (mineral wool) insulation in the interior walls may offer significant decrease in sound transferance btwn those 2 walls- Make sure they use at least 5/8" sheetrock - 2 staggered layers would be better

Link to company that I have purchased from in the past (no affliation w/them) - they are an excellent resource - very helpful people

Good luck

Here is a link that might be useful: soundproofing

Two words: ear plugs. Just a thought from someone whose dh is a LOUD snorer.

Try using "Quietrock" drywall. Expensive but it is the equivalent of 8 sheets of drywall on a wall.
I just used this in a lawyers office renovation we did with very good results.

Totally agree with jejvtr -- using cast iron drain pipe will eliminate a lot of noise from flushing toilets.

We have a 1975 split level home that has black pvc drain pipes. Whenever the upstairs toilet is flushed you can hear the "falling" water in the FR. We will be replacing just the pvc drops with cast iron. We're told you only need to replace the vertical drop portion, not the entire drain system.