Why Does My Tap Water Turn Cloudy and Gritty After Running Clear?

  • Thread starter Thread starter Envergure
  • Start date Start date
  • Tags Tags
    Strange
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
Sign up Log in
6 replies · 5K views
Envergure
Messages
6
Reaction score
0
(Maybe this is the wrong forum; Whatever, it's an unexplained phenomenon to me.)

They're always messing with the plumbing in my dorm. After the last time, the water started behaving strangely when they turned it back on.

When I run the water into a glass, it comes out clear. It then turns cloudy (with gas bubbles) over the course of about 30-60 seconds. The bubbles then float to the top.

The bubbles nucleate throughout the liquid, not on the glass walls. The water doesn't have an odd taste to it, but it does leave a sort of gritty sensation in my mouth, like there's some silt suspended in it.

The main questions are 1) How did the tapwater become silty and supersaturated with air?, and 2) Why does the gas wait to be poured to effervesce?
 
Chemistry news on Phys.org
Envergure said:
(Maybe this is the wrong forum; Whatever, it's an unexplained phenomenon to me.)

They're always messing with the plumbing in my dorm. After the last time, the water started behaving strangely when they turned it back on.

When I run the water into a glass, it comes out clear. It then turns cloudy (with gas bubbles) over the course of about 30-60 seconds. The bubbles then float to the top.

The bubbles nucleate throughout the liquid, not on the glass walls. The water doesn't have an odd taste to it, but it does leave a sort of gritty sensation in my mouth, like there's some silt suspended in it.

The main questions are 1) How did the tapwater become silty and supersaturated with air?, and 2) Why does the gas wait to be poured to effervesce?

This occurs when the water in a pressurized system is turned off, then on. You ARE In fact feeling sediment, and when you first turn on the tap it probably hisses or "blasts". There is air in the pipes, and the water mixes with it; the force breaks the large bubbles into miniscule ones, which makes the water appear cloudy until the air rises.

edit: A great example is a fire hydrant that is worked on a street; you'll see "brown" water (rust mostly).
 
I get this a lot with the hot water.

Cold will be crystal clear (ah the beauty of living in Wales) but the hot water will come out cloudy (air bubbles not dirt).

At first I was worried, but I've been to a number of places and they all get the same thing with the hot water.
 
jarednjames said:
I get this a lot with the hot water.

Cold will be crystal clear (ah the beauty of living in Wales) but the hot water will come out cloudy (air bubbles not dirt).

At first I was worried, but I've been to a number of places and they all get the same thing with the hot water.

Your hot water is probably pneumatically driven, rather than gravity/source-pressure for the cold?... After all you have to store and heat water, taking it out of the normal circuit.
 
nismaratwork said:
Your hot water is probably pneumatically driven, rather than gravity/source-pressure for the cold?... After all you have to store and heat water, taking it out of the normal circuit.

It's pump driven, but it's a Combi system which doesn't store the water. It heats it on demand straight from the mains.

Better because it gives you almost instant hot water, but worse because in a power / gas failure you have no tank of warm water.
 
jarednjames said:
It's pump driven, but it's a Combi system which doesn't store the water. It heats it on demand straight from the mains.

Better because it gives you almost instant hot water, but worse because in a power / gas failure you have no tank of warm water.

I'm familiar with your strange showers and weak pumps! :wink:

Actually, they're starting to become popular in the states now as well, which is good for all of the reasons you listed.

Seriously though, 16 years ago the situation was miserable with your hot water however... I had better showers in Tikal. :-p
 
This is perfectly normal, but doesn't look it. I've seen it happen with hot and cold water.