Lead in tap water comes from your pipes, not the plant
DC, Arlington and Alexandria still have lead service lines in older neighborhoods, and any home built before 1986 may have lead solder. The water leaving the plant is lead-free; it picks lead up on the way to your glass. Treatment at the tap is the answer.
Signs you have it
- Home built before 1960 in DC, Arlington, Alexandria, Takoma Park or Hyattsville
- Home built before 1986 anywhere (lead solder was legal until then)
- Utility notice that your service line is lead or unknown
- Older brass faucets and fixtures
What causes it
Lead service lines, lead solder on copper joints and older brass fixtures release lead into standing water, especially overnight and in warm weather. Chloramine can make older plumbing more prone to leaching than chlorine did, which is why DC adds a corrosion inhibitor.
In the DMV specifically
DC Water's Lead Free DC program is replacing lead service lines across the District and recommends point-of-use filters certified for lead in the meantime. Arlington and Alexandria have their own replacement programs. Suburban homes built after 1986 rarely have lead sources beyond older fixtures.
What fixes it
Recommended
Reverse osmosis certified for lead
NSF/ANSI 58 reverse osmosis reduces lead by well over 95 percent at the tap you drink and cook from.
Also useful
NSF/ANSI 53 lead-certified filter
A point-of-use carbon block filter certified specifically for lead is a lower-cost option for a single tap.
Also useful
Replace the service line
The permanent fix. Check your utility's lead service line map and replacement program; the filter covers you until it is done.
What does not work
- Whole-home softeners or carbon tanks (not certified for lead and installed upstream of the fixtures that release it)
- Boiling (concentrates lead)
- Pitcher filters not specifically certified to NSF/ANSI 53 for lead
Related questions
How do I find out if I have a lead service line?
DC Water, Arlington and Alexandria publish lead service line lookup maps online. Your utility is also required to notify you if your line is lead or unknown.
Should I run the tap before drinking?
Yes, flushing 30 seconds to 2 minutes after water has sat for hours reduces lead. It is a stopgap, not a fix, and it wastes water. A certified filter is the reliable answer.