A new faucet, a repaired supply line, or a freshly soldered joint can leave a metallic taste in the water. Some St. Louis homes have older copper or galvanized pipe alongside newer sections, so plumbing work is a common reason a tap suddenly tastes different. You can narrow down the cause with a few observations before you test anything.

Notice Where the Taste Shows Up

Start by checking which faucets carry the taste. Run the cold tap in the kitchen, then the bathroom sink, then any outdoor hose bib. If only the hot side tastes metallic, the water heater or hot supply lines are the likely source. If both sides taste off, the cause is more likely in the main line near the meter or in the water coming from the street. If one fixture alone tastes off, look at that fixture first.

Check the Timing

Think about when the taste started. A taste that appeared the day after work was done on the plumbing points toward new materials settling in. Solder flux, the paste used on copper joints, is meant to be rinsed away, but it can leave residue if the lines were not flushed well. A metal taste that fades over days or weeks often comes from that initial conditioning. A taste that stays steady for months may point to something else, such as corrosion in an older section of pipe.

Flush the Line Before Testing

Water that sits in pipes overnight picks up more from the metal around it. Before you collect a sample, run the cold tap for a few minutes until the water runs cold from the street side. Then collect a sample in a clean glass container. Compare it with a sample taken after the water has sat for several hours. If the sample taken after sitting tastes stronger, the metal contact is likely in the pipes or fixture rather than the main supply.

Look at the Fixtures

Faucets, aerators, and supply connectors can all carry residue or small particles from new installation. Unscrew the aerator at the tip of the faucet and rinse it under running water. Look for flakes, grit, or a dull coating. Inspect the flexible supply lines under the sink, especially any fittings that were added recently. If the taste clears after cleaning the aerator, the source was local to that fixture.

Use a Test Kit for the Basics

Home test kits can help you sort out general water chemistry, such as hardness and pH, which affect how water tastes and how it reacts with metal. Some kits also check for copper or iron. Read the instructions closely, use a clean container, and compare the color against the chart in good light. Home kits give a rough indication rather than a laboratory result, so treat them as a first step.

When to Send a Sample to a Lab

If the taste is strong, persistent, or coming from a fixture you use for drinking or cooking, a certified lab test gives a more reliable answer. Ask the lab to test for the metals you are concerned about, and ask specifically whether they test for lead. Older homes in St. Louis may have lead in service lines, solder, or fixtures, so it is worth asking even if the taste seems mild. Your water utility also publishes annual water quality information, which can help you understand what the supply carries. Compare any lab report against the reporting limits listed for each contaminant.

What to Do While You Wait

  • Run cold water through the kitchen tap for a few minutes after the water has sat unused for a long time.
  • Use cold water, not hot, for drinking and cooking, since hot water tends to draw more from the plumbing.
  • Clean or replace the aerator on any fixture that tastes off.
  • Keep a short note of when the taste started and what plumbing work was done nearby.
  • Check whether the taste changes after the line has been flushed on a few different days.