Rif Brachot 41b

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41b

{Chullin 106b continues}
and anything which separates in regard to immersion separates in regard to washing hands, in terms of chullin, and in kiddush of hands and feet in the Temple.

And we conclude in the name of Rabbi Yehoshua ben Levi that "until the joint applies" both the chullin and teruma {stringently, that is until the third joint in the gav of the hand.}
And so is the halacha.

Rav said: a man may wash his hands in the morning and make the condition upon them {that the washing should apply, for eating} for the entire day.

{Chullin 107a}
Ravina said to the Benei Pakta of Arvut: that ones such as yourselves who do not have much water may wash your hands in the morning and make the condition upon them for the entire day.
Some say this is only in pressing circumstances, and this then argues on Rav's statement.
And some say this is even not in pressing circumstances, in which case this is {exactly} the statement of Rav.

Rava said: this irrigation ditch {a pipe into which they pour water from the river and it brings the water into the field}, we do not use it to wash our hands {netilat yadayim}, and we do not immerse our hands in it. We do not immerse our hands in it - for it is drawn water, and we do not wash our hands with it, for it comes not from human strength {koach gavra}.