ᐅ Yellowish-brown water coming from the tap...

Created on: 23 Mar 2026 09:11
P
Pianist
Good day!

Yesterday, I removed my 26-year-old dishwasher because a new one is being installed today. Beforehand, I turned off the main water supply as a precaution and drained the remaining water from the lowest outlet point. I wasn’t sure if the shut-off valve was completely tight.

I then screwed on a blank cap and sealed it with Teflon tape, just to be safe. When I reopened the two main valves, yellow-brown water came out of all the taps on every floor.

The situation cleared up quickly, but I’m still wondering: where did that water come from? It seems that by shutting off and draining the system, I mobilized some stagnant water that had been sitting there for a long time and was now released. I tend to think it originated from the hot water side.

The house is as old as the dishwasher.

Does anyone have an idea? Many thanks!
P
Pianist
24 Mar 2026 12:13
Hmm... I just realized that the heat exchanger seems to be heavily scaled because warm and cold water alternate continuously, and the water flow from the showerhead has generally decreased over the past few years...