Said It Here

Should I remove an old mixing valve during a renovation?

Old mixing valves take up valuable space and complicate plumbing layouts, leaving renovators unsure whether to cap them off and switch to a direct single supply or simply leave them in place. Tackling this removal requires altering copper pipes and handling dual-to-single outlet conversions, which makes homeowners weigh the effort of a DIY fix against the risk of future leaks.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    leaving the old valve in place
  2. 2
    having a plumber remove the valve and hook up straight cold water
  3. 3
    Leaving the tempering valve in place
  4. 4
    Checking if it feeds other fixtures like the bathtub

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/Plumbing2 people · September 2026

“I am renovating this bathroom so toilet is out, and we have to patch drywall elsewhere anyway. Would you recommend having the valve removed at this point and just hooking up straight cold? Or just leaving it alone and assume it'll continue to be fine?”source ↗

pennyonthetraintrack · r/Plumbing · 1 upvotes

“Is this something that can be removed? It takes up a lot of room under the vanity.”source ↗

“Can this be a DIY job? Is it possible to remove it, switch the valves from dual outlet back to single outlet (for the sink), and then put a stopper on the copper outlet pipe?”source ↗

Rare_Inevitable9992 · r/Plumbing · 1 upvotes

Where this came up

People with this problem also raised