Riders aren't supposed to bring water on buses or trains but because of the heat wave that is gripping the D.C. region, Metro is temporarily lifting that ban.

WASHINGTON – Metro is lifting its loosely-enforced ban on drinking water on trains and buses July 3 and July 4 due to the extreme heat hitting the D.C. region.

“The exception to Metro’s ‘no eating or drinking’ policy applies to water only – in stations and aboard trains, buses and MetroAccess vehicles,” Metro said in a statement.

The food and drink ban, which riders do not always follow, is legally enforceable in Maryland, Virginia and D.C.

Metro Transit Police officers will not enforce it against water bottles Tuesday or Wednesday, although it is infrequently enforced anyway.

Metro said all chillers in indoor Metro stations are working. Those chillers cool the air somewhat in stations but become less effective as the “feels like” temperature outside rises above 100 degrees.

Air conditioning in rail cars is usually more effective, bringing the temperature down about 20 degrees.

Metro asks riders who are not feeling well to ask a station manager to call for medical help.