Answer:

water

Answer	Crossword Clue
WATER	Bather's need
WATER	Marathon handout
WATER	No-cal drink

WATER	Well content?
WATER	What ten theme answers contain
WATER	Aquarium contents
WATER	Homeowner's monthly expense
WATER	What carbon dioxide reacts with to form carbonic acid
WATER	Short-supply item in the news
WATER	Spring flower?
WATER	Desert cry

WATER	Give the plants a drink
WATER	Aquafina product
WATER	Desert request
WATER	Dilute, with "down"
WATER	Word that can precede either part of the answers to starred clues
WATER	Drink disparaged by W.C. Fields
WATER	Plant need
WATER	-

WATER	Important greenhouse gas
WATER	Kind of chestnut or polo
WATER	Moisten the marigolds
WATER	No-calorie beverage
WATER	Desert wanderer's request
WATER	10K race handout
WATER	Tend to, as flowers
WATER	Firefighting need

WATER	Radiator filler
WATER	Tend the plants
WATER	What rises in a flood
WATER	Zero-calorie beverage
WATER	Marathoner's need
WATER	Evian product
WATER	Irrigate
WATER	Feed a plant

WATER	Feed, in a way
WATER	It freezes at 32 degrees F
WATER	Freshen up the freesia
WATER	Power or proof start
WATER	Restaurant freebie