Why Did the Tap Water Suddenly Change Color?

Posted on: 30 May 2018

It's never a nice sight when you turn on a faucet in the office kitchen and find the tap water has turned brown, red, yellow, speckled, or some other color. Tracing the problem isn't always easy, but most of the time, you can get a pretty good idea of what's going on. Your first step is to check with the facilities department and see if the city has been flushing out the utility lines; that can knock sediment and rust into the water. But if the city hasn't been doing anything, you may need to do a little more investigating.

Cold vs. Hot

First, is this happening with just cold water, just hot water, or both? If it's just hot water, you've got a problem with your hot water heater or the lines running from the heater. At that point, you need to call a plumber who works with commercial water heaters to find out exactly what's going on.

If the problem is happening with just cold water but not hot, one of two things is going on. One is that the problem is coming from the water main or lines outside the building, but it's such a new problem that the water in the water heater tank is still OK. In other words, when you turn on the cold water, you're getting that strange water straight from the main. But when you turn on the hot water, you're getting stored clean water from the tank. The other possibility is that there is something wrong with the cold water pipes.

You also need to take a look at location. Check whether this is happening at just one faucet or at several (or all plus toilets).

Red vs. Something's Off

The color can give you a clue as well. Reddish or reddish-brown water that looks rusty probably is filled with rust, and that points to either a line flush or some sort of work that knocked rusty residue off the sides of the pipes and into the water. If the water is somewhat yellowish or a light brown, that could be from algae in the water supply (very common in summer, and your water utility company should have more information) or sediment. Is anyone doing relandscaping or relocating a water pipe? That could have introduced more sediment into the water supply.

Solving the Problems

For water-heater problems, as mentioned, you need commercial plumber services. For the other issues, in most cases, flushing the pipes out by running all the faucets for a while should work. Yes, that does use a lot of water, but that's really all you can do.

If flushing is not working, then get a plumber onsite to take a look at the pipes. While most of the things that can change water color are safe and temporary, don't just assume things will be fine if you can't get clear water after several minutes of running all the taps. You need to find out why the water isn't improving.