In most of the US, water from the tap is safe to drink. Public water systems are regulated under the federal Safe Drinking Water Act, and the EPA sets limits for harmful substances. Restaurants serve tap water for free.
Your water company publishes a yearly Consumer Confidence Report (also called a water quality report) by July 1. Search your city name and "water quality report", or look on your water bill.
If there is a problem, the water company must tell the public. Sign up for your city's alerts.
Taste and smell can differ from home. A little chlorine smell is normal; it kills germs.
Homes built before 1986 may have lead pipes or lead solder. Lead is harmful, especially to babies, children and pregnant people.
If water has been sitting for hours, run the cold tap for a short time before drinking.
Use cold water for drinking, cooking and baby formula. Hot water can pull more lead from pipes.
Ask your landlord or water company if your building has a lead service line. Many water companies offer free or low-cost testing.
A filter certified to remove lead (look for NSF/ANSI 53 on the box) reduces it.
In rural areas, some homes use a private well. The EPA rules do not cover private wells. The owner is responsible for testing. Ask the landlord for recent test results, or contact the county health department.
During a boil water notice (see the guide on outages and boil-water notices).
From a bathroom tap labeled "non-potable" (not for drinking), or outdoor hoses.
If the water company or health department says so.
Spending a lot on bottled water every week. A refillable bottle and a filter jug cost much less.
Using hot tap water to make baby formula.
Assuming a filter fixes everything. Each filter is certified for specific problems; read the box.