Water that turns yellow, tan, or brown for a while after work on the street is common in St. Louis neighborhoods. Crews working on water mains can stir up loose sediment and rust that has built up inside older iron pipes, and that material can travel into nearby homes. Discolored water can also point to a problem that needs a call to your water provider, so it helps to sort out what you are seeing before deciding what to do.

Start with the pattern

Look at which taps are affected. Discoloration at every cold tap in the house usually points to the supply coming into the home. Discoloration only at hot taps points to something inside the house, most often the water heater, where sediment collects at the bottom of the tank over time.

Check one cold tap

  • Choose a cold tap close to where the water line enters the home, such as a basement utility sink or an outdoor hose bib on the same supply.
  • Run it at a steady flow and hold a clear glass up to a window or a light to judge the color.
  • Hold a plain white cloth or white bowl under the flow as well. Rust-colored water often leaves a stain on white laundry, which makes the color easier to judge.
  • Watch whether the color fades over several minutes. Water that gradually clears is usually sediment being pushed out of the line.
  • If the water stays dark or gets worse, move on to the next checks and note what you saw.

Check the hot side separately

If cold water runs clear and only the hot water is discolored, the water heater is the likely source. Sediment and minor rust can collect in the tank and get stirred up when supply conditions change. Before doing anything with the tank, turn off the heater power or gas supply and let the water cool, then follow the manufacturer's instructions for your model. Leave gas and electrical connections alone unless you are qualified to work on them.

Look for a notice

Check your water provider's website, any door hanger left at the house, or a recorded message line for notices about nearby main work or line flushing. Crews sometimes flush lines in a neighborhood after repairs, which can cause temporary discoloration in many homes at once. If neighbors on your block report the same thing, pass that along when you call, because it helps the provider trace the cause.

Write down what you see before you call

  • Which taps are affected: hot only, cold only, or both
  • The color, and whether it changes over time or after the water runs for a while
  • The date it started and any street or sidewalk work you noticed nearby
  • Whether the water has a strong smell or taste, or leaves stains on laundry or fixtures

When to call for help

Contact your water provider if the discoloration affects the whole home, lasts beyond a short period, or comes with an odor, an unusual taste, or a drop in pressure. A licensed plumber can check interior piping if the problem stays inside the house after the supply has cleared. Until you have a clear answer from your provider, avoid using discolored water for drinking or cooking, and keep it out of baby formula and pet bowls.

Keep the record

A short written log is useful even if the problem clears on its own. Note the dates, the taps involved, and what the water looked like. If the discoloration returns later, that history helps your provider and any plumber you bring in move faster. A simple log in a kitchen drawer or on a phone takes only a minute to start and can save time on the next visit.