Snake blood does not actually hydrate you and instead can dehydrate you and could even make you sick just by drinking it.
You cannot drink blood when thirsty as while blood is essential for the body to sustain life it is poisonous to actually drink blood.
You can become very sick from drinking blood and especially if you drink it everyday or drink animals blood or other peoples blood.
Blood can also carry various viruses and infections which can lead to you contracting those infections and viruses.
If you licked a little blood of your own then it's unlikely that you would get sick but you should not drink it.
Drinking blood can also dehydrate you instead of hydrate you due to the salt it contains.
Human blood contains about 9g of salt per liter.
Those 3 liters you're drinking each day would give you around four and a half times your RDA, which would lead to dehydration and kidney failure if you didn't also drink lots of water, and hypertension if you did.
You should always keep plenty of water with you and especially if going out camping, hiking, boating etc in case you get lost or cannot get help right away.
Drinking water from a pond or creek would be better for you than drinking any blood but water from a creek or pond or lake could also contain bacteria that could make you sick but it's less likely to make you sick and is more hydrating than blood from humans or other animals.