(WUSA9) --- The Federal Emergency Management Agency recommends one gallon of water per person per day, for drinking and sanitation.
However, FEMA suggests doubling that in very hot temperatures, which is certainly what we are experiencing this week.
The agency says a three-day supply per person for each day is best.
Children, nursing moms, older folks and anyone with a medical condition may need extra hydration.
WUSA 9's health team spoke with the Vice-Chairman of the Emergency Department at Medstar Southern Maryland Hospital Center who says they've already been treating people with heat-related illnesses and dehydration. And some of the symptoms aren't ones you would immediately recognize.
Watch video to find out the symptoms.
The elderly also lose their sense of thirst, so it is important to check up on them during hot weather.
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