Discolored Water: Causes and Solutions

The Portland Water Bureau’s Bull Run Watershed, one of TVWD’s water sources, is an unfiltered surface water source. During periods of heavy rain, such as fall and winter, organic matter and sediment levels can temporarily increase in the Bull Run watershed, which can alter the color of the water. This can impart a yellow tint to your water, similar to tea. This is primarily due to natural organic materials, such as tannins from decaying vegetation in the Bull Run Watershed. 

Discolored water can occur due to planned maintenance or unexpected disruptions in the water system. Over time, naturally occurring sediment accumulates at the bottom of water mains. Occasionally, this sediment may make its way into your home’s plumbing. Activities such as fire hydrant use, main breaks, or nearby water system construction/maintenance may disturb sediment that has settled in the water mains, causing it to enter your home when you turn on your tap.

Typically, the water clears on its own within a few hours, often much sooner. To help manage sediment, TVWD conducts routine water main flushing. Signs are posted in areas where crews are working, and updates are provided on our Flushing Program page.

If your water appears discolored, follow these steps:

Let’s start with your COLD-WATER system.

• Turn off all taps inside your home. Then, open all spigots on the outside of your home. Run water at each spigot, one-by-one, until it runs cooler and clearer, then turn them all off.
• Next, go inside. Turn on the cold water at your kitchen sink until it runs cooler and clearer. Repeat this turning on the tap one-by-one at each bathtub, sink, and shower in your home.
• If your home has multiple stories, start downstairs and move up one level at a time. Repeat this process until you’ve flushed all the taps in your home.
• If discolored water persists in one tap, continue to flush that tap until water appears clearer.
• For fastest results, flush your toilets often so the water turns clear more quickly.
• Remember that discolored toilet water might be a result of cleanliness in the bowl and may not be a result of the new water supply.
• If you don’t use your taps for several weeks, discoloration might return. In this case, you can repeat the flushing process. 

If your hot water is discolored, you can flush that system in the same way.  

• Turn on the hot water at each tap one at a time. Let each run until it’s clear. If your home has multiple stories, start downstairs and move up one level at a time.
• If water continues to run hot but remains discolored, your water heater may need to be flushed. In that case, you should contact a licensed plumber to flush the water heater tank. 

These steps are for a single-family home. If you live in an apartment or condo, contact your maintenance representative for help.

If your water does not clear after these steps, contact TVWD at (503) 848-3000.

In older homes with galvanized pipes, discoloration may result from the plumbing itself. This is often noticeable:

• First thing in the morning, or after long periods of low or no water use.
• At seldom-used faucets.

To resolve this type of discoloration, please follow the steps below.

Let’s start with your COLD-WATER system.

• Turn off all taps inside your home. Then, open all spigots on the outside of your home. Run water at each spigot, one-by-one, until it runs cooler and clearer, then turn them all off.
• Next, go inside. Turn on the cold water at your kitchen sink until it runs cooler and clearer. Repeat this turning on the tap one-by-one at each bathtub, sink, and shower in your home.
• If your home has multiple stories, start downstairs and move up one level at a time. Repeat this process until you’ve flushed all the taps in your home.
• If discolored water persists in one tap, continue to flush that tap until water appears clearer.
• For fastest results, flush your toilets often so the water turns clear more quickly.
• Remember that discolored toilet water might be a result of cleanliness in the bowl and may not be a result of the new water supply.
• If you don’t use your taps for several weeks, discoloration might return. In this case, you can repeat the flushing process. 

If your hot water is discolored, you can flush that system in the same way.  

• Turn on the hot water at each tap one at a time. Let each run until it’s clear. If your home has multiple stories, start downstairs and move up one level at a time.
• If water continues to run hot but remains discolored, your water heater may need to be flushed. In that case, you should contact a licensed plumber to flush the water heater tank. 

These steps are for a single-family home. If you live in an apartment or condo, contact your maintenance representative for help.

Most often, cloudy or milky water is caused by tiny air bubbles, not sediment. This happens because water under pressure holds dissolved air, which is released when the pressure drops as water exits your faucet. Cold water exacerbates this condition, as it holds more dissolved air than warm water.

Cloudy water typically clears on its own after sitting for a short time and is not a public health concern. Air in water can also occur after certain system repairs or flushing activities.

For more information about water quality and discolored water, visit our Water Quality FAQs page.