On Saturday the Post reported on a set of D.C. Water and Sewer Authority test results from 2006 that show major lead level spikes in the tap water of hundreds of homes just after lead pipes near them were replaced. The test results were obtained through a freedom of information act request by Virginia Tech professor Marc Edwards.

WASA has spent $93 million since 2004 in an effort to reduce lead contamination in residential tap water through a series of partial pipe replacements. What this means is that WASA has been replacing public portions of lead service lines, while leaving homeowners responsible for replacing lead pipes that are on their property. What these 2006 test results show is that the practice of partial pipe replacement has actually made the problem worse -- when the lead service pipes were cut in half and joined to new pipes, lead shavings began being released directly into the flow of tap water into homes.

For those of you who don't recall, WASA admitted in early 2004 that two-thirds of the 6,118 residences they had tested had water that exceeded the lead limit of 15 parts per billion. The agency didn't do a good job alerting the public to the danger until an all-out panic ensued. The estimated number of homes affected eventually rose to around 23,000, and city officials responded by distributing free Brita filters and testing kits to eligible residents - although more recent studies suggest consumer-grade water filters don't actually filter lead anyway (h/t Kramestopher's Blog). WASA announced later that year that it would begin a comprehensive plan to rid the city of lead pipes once and for all.

This latest report shows that tap water drawn from 658 homes within a week after the agency partially replaced their lead service lines had average lead levels of 260 parts per billion, 17 times the amount the federal government considers unsafe in drinking water.

Perhaps more disconcerting is that fact that we are only hearing about this now, from an independent scientist, rather than from WASA itself. The agency has apparently not been following up to determine the effectiveness of its partial pipe replacements, and General Manager Jerry Johnson offered only the weak rebuttal late last week that he believes the practice causes only a short-term problem that is resolved by customers running their taps for a minute or two before drinking the water. Our question is: if that's the case then when, exactly, did customers receive notice in 2006 or 2007 that they should be running their tap water for 1-2 minutes before they drink it?