Said It Here

Air coming out of hot water lines only

Trapped air in hot water lines is often caused by a failing or recently replaced water heater that generates gas or allows air to enter the tank. Running the taps only offers a temporary fix because the underlying source of the air inside the system hasn't been resolved.

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
    Keeping the water dripping when it is cold
  2. 2
    Checking if the valve underneath is all the way on
  3. 3
    Running the tub and sink on hot for five or so minutes to flush out air.

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/HomeMaintenance1 person · September 2026

I had my hot water heater replaced a week ago, and the hot water is still milky and has a sort of sour fruit smell to it.source ↗

My friend advised me to run my tub and sink on hot for five or so minutes to flush out the air, but this only worked for a few hours tops before returning again.source ↗

jeneveuxpassavoir · r/HomeMaintenance · 1 upvotes
r/Plumbing1 person · September 2026

It’s only happening with hot water, it’s an older house and I’m not sure when the water heater was last replacedsource ↗

rlykhj · r/Plumbing · 1 upvotes

I’m just trying to figure out why bc the air isn’t going awaysource ↗

rlykhj · r/Plumbing · 1 upvotes

It’s with all the sinkssource ↗

rlykhj · r/Plumbing · 1 upvotes

Where this came up

People with this problem also raised