I am in a river, but not in a lake, I am in computer, but not in a T.V, and I am in rain, but not in snow, What am I?

Question

From house to house I go,
Sometimes wide, Sometimes narrow,
I always stay outside,
Whether there's rain or snow.
What am I?

Answer 1

Letter R .
R is in RiveR, R is in computeR , R is in Rain.
But R is not in lake, TV, or snow.

Answer 2

The letter "R"

Answer 3

Alphabet "R"