The National Institutes of Health owes the Washington Suburban Sanitary Commission almost $1 million, and more than $491,000 of that balance is overdue, according to officials at the water and sewer utility.
NIH owed the water and sewer utility more than $1.46 million before it made a $508,216.17 payment Nov. 21, according to WSSC officials.
No other federal agency has an account as large, said I.J. Hudson, a spokesman for the WSSC, which serves 1.8 million customers in Montgomery and Prince George's counties.
WSSC expects another payment from NIH this week, Hudson said.
NIH's delinquent debt accounts for much of the more than $670,000 in delinquent governmental accounts owed to the WSSC in November, according to the utility.
But federal agencies aren't the only water and sewer users who are months late in paying the utility.
Delinquent accounts owed to the WSSC totaled more than $8.4 million last month, according to the utility's November delinquency report.
In April 2011, nearly one in 11 WSSC customers were late paying their bills, and the overdue total exceeded $12 million.
In an emailed response, Bradley Moss, a spokesman for NIH's Office of Research Facilities, said that the institutes believe two bills, in June and August 2012, were processed late. The first bill was paid and the second was endorsed for payment Nov. 27 and should be remitted by the Department of Treasury to WSSC in the next few days, Moss said.
With that considered, Moss said, NIH believes it has a zero balance.
When NIH payments are late, the institutes pay a penalty fee based upon Department of Treasury rates, according to Moss.
NIH is studying means by which the payments can be processed in a more automated fashion, Moss said.