Why not cut back your mate consumption to only one L (and don't eat the leaves), and substitute other liquids for the rest.

I would skip the juice idea- it is usually full of sugars. If your choice is to have other herbal teas, don't just have one kind.

Just a question. Have you ever had your blood sugars tested? Extreme thirst can be a sign of diabetes.

3 to 5 liters of juice would be a lot of fructose. 3 to 5 liters per day of anything other than water sounds like a lot, but an active adult may very well need that much water daily. Add about a liter per hour of strenuous physical activity. Prudence would dictate moderation in the intake of anything, including teas. If you don't like the taste of water, you can divide your daily intake between several different beverages, so you're not getting too much of any one beverage. I drink my water with a twist of lemon, which gives it flavor but not too much fructose.

I drink only water, green tea (in the morning only), and (occasionally) roibos tea.

I also think it's important to rotate what you're drinking. Bone broth is great in a mug, but it would probably get old for every beverage. Herbal teas are good, as are infusions. I also like to add a little lemon juice or unsweetened cranberry juice to my water for flavor.

Water is really best. Non-caffeine herbal teas like Rose Hips etc. shouldn't be bothersome, but if you drink them in large quantities, water them down and change them up. Bone broth is great. Lemon/lime in water is good, too. Teas with caffeine or stimulants like Mate probably shouldn't be consumed in large quantities, though I love my morning coffee. Perhaps the stimulant in Mate makes you thirsty and it has become slightly addicting?

I agree with Anna, you are drinking a lot of fluid there!!!! A personal question here, what does your urine look like? Is it dark for most of the day or dark and then very light as the day progresses? Dark urine may mean you are not hydrating properly and is something you should seek medical advice for esp. in regards to diabetes. And another question: do you eat paleo?

It is really nice to drink hot water alone. The taste is really quite pleasant, but you may not be ready for that yet, so why not try adding a flavor, why not try ginseng root? A slice of fresh ginseng root can be boiled up or just popped into boiled water, which will certainly take the edge off the plain ol' water taste. Ginseng has many health benefits.

There are other Chinese herbs you can take esp. if you are experiencing fluctuations in blood glucose/diabetes and many can be boiled in water to give a pleasant tasting drink which can been taken during the day. I would advise seeing a Chinese herbalist to get a full test done, you will then be given the herbs from him/her.

If you are used to making up and drinking the mate, Chinese herbs may offer a kind of substitute to your 'tea ceremony' until you can graduate to plain hot/cold water.

If you really can't face any of the above stuff, it is OK to start with juice of you then top it up with water gradually - so start on the first day with regular juice and on the second day water it down until it tastes weaker and drink that, then continue to water it down until you have a very small amount of juice per water ratio. This is a technique I used on my children who couldn't bare the thought of drinking water one summer a while back, within a week they were on 100% water, no juice, no complaints.

I'm personally a big fan of fermented drinks like fermented coconut water and kombucha. If you have water kefir grains you can ferment the sugar out of anything and make it a sparkly soda. Wild Fermentation, a great book, even discusses someone using Mountain Dew....but I have personally used it on the aforementioned coconut water, apple juice, and cranberry apple juice.

I think too much of anything is probably bad (even water!)

That said, I think there is some pretty strong epidemiological evidence for health benefits from over 10+ cups of green tea a day. IIRC all the markers they measured health against were improved the more tea was consumed (the studys top amount was 10+ cups)

5 litres is a lot to drink of anything, it seems to me. I would try going with just water for a while and see if the thirst dies down, and if it doesn't, see a doctor. I also would like something other than water to drink, but haven't found anything really satisfying. I like yerba mate, but do not drink it because of the caffeine and other xanthines. It has a lot of caffeine. I also love real tea, but avoid it now for several reasons. One is the xanthines, and another is that it has very high levels of fluoride and aluminum, both of which are rather poisonous, and neither of which is needed in any level in the body. I wonder about all the people who recommend drinking green tea, including Andrew Weil. What do they think about the fluoride? Regular tea consumption would mean you're getting more than if you had a fluoridated water supply.