How Lead Enters Your Drinking Water
Lead does not usually come from the original water source — it enters your drinking water through corrosion of plumbing materials. This process, known as leaching, occurs when water sits in pipes, solders, or fixtures that contain lead. The older your home and plumbing infrastructure, the greater the potential risk.
Key sources of lead in drinking water include:
- Lead service lines: Many homes and buildings built before the 1980s have lead service lines connecting the municipal water main to the home. These are the single largest contributor to lead in tap water.
- Lead solder: Until 1986, solder containing lead was commonly used to join copper pipes. Even small amounts of leaching can elevate lead levels.
- Brass faucets and fixtures: Older brass components — including some sold after lead regulations were tightened — can contain meaningful amounts of lead.
- Municipal distribution systems: In some older cities, portions of the water distribution infrastructure may still contain lead components.
Factors That Increase Leaching
Not all lead-containing plumbing leaches at the same rate. Several factors increase the amount of lead that dissolves into your water:
- Water acidity (low pH): More acidic water is more corrosive and dissolves lead more readily.
- Water softness: Soft water with low mineral content tends to be more corrosive than hard water.
- Water temperature: Hot water leaches lead more quickly than cold water — never use hot tap water for drinking, cooking, or making formula.
- Standing time: Water that has sat in pipes for several hours accumulates more lead. This is why first-draw water from the tap can have higher lead concentrations.
Who Is Most at Risk?
While lead in water is a health concern for everyone, certain groups face heightened risk:
- Infants and young children — especially those fed formula made with tap water — absorb a higher percentage of ingested lead and are more vulnerable to its neurological effects.
- Pregnant women — lead can be transferred to a developing fetus.
- People living in older housing stock with original plumbing.
Practical Steps to Reduce Lead in Your Water
- Flush your tap before use. Run cold water for 30 seconds to 2 minutes if the water has been sitting. This flushes out water that has been in direct contact with lead-containing pipes.
- Always use cold water for cooking and drinking. Hot water dissolves lead faster and should never be used for food preparation or baby formula.
- Install a certified water filter. Look for filters certified by NSF International to Standard 53 for lead removal. Pitcher filters, faucet-mounted filters, and under-sink systems are all options.
- Get your water tested. Contact your water utility or an accredited lab to test your tap water for lead. This is the only way to know your actual exposure level.
- Ask about your service line. Contact your local water utility to find out if you have a lead service line and whether there are replacement programs available.
- Replace old fixtures. If your home has older brass faucets or plumbing fixtures, consider replacing them with clearly labeled lead-free options.
Understanding Water Test Results
The EPA's action level for lead in drinking water is 15 parts per billion (ppb). However, the EPA has stated that there is no safe level of lead exposure, and many health experts recommend taking action even at lower levels — particularly in homes with young children. If your test results show any detectable lead, it is worth investigating the source and implementing protective measures.
If you rent, your landlord may be required to disclose known lead hazards and address them. Contact your local health department if you are unable to get cooperation from a landlord.