The build up to 363.7 million barrels was unexpected. It put stockpiles close to the upper range for this time of year, the federal agency said.
Despite a shutdown of non-essential government services, the EIA published its weekly report. News reports say the agency has the funding to operate until Oct. 11, which means that it could produce another weekly oil supply report before it is put on hold due to the shutdown.
The agency said supplies of motor grade gasoline rose by 3.5 million barrels to 219.7 million barrels and are at the top of the average range for this time of year.
Supplies of distillate fuels, which include home heating oil, fell by 1.7 million barrels to 129.2 million and remain near the lower limit of the average range for this time of year.
The national average retail price of regular unleaded gasoline fell in the week, dropping for the fourth consecutive week.
The national average fell by 7 cents to $3.425 per gallon. The price is 37.9 cents per gallon below the price in the same week of 2012, the EIA said.