Water tastes salty. How can I help her stay hydrated?

It may be more productive to give her "juicier" foods, like grapes, watermelon, celery, oranges, cucumbers, cauliflower, popsicles, etc.

There is a product called "Jelly Drops" that are specifically made for hydrating.
They are like a giant jelly treat. So, elderly people can eat them easily. They don't stick to teeth or anything. they quickly turn into water but do not burst when you bit them.
It was created by a man to keep his elderly grandma hydrated.
Just look at Jellydrops.com

Do YOU taste your home water as salty too, or it just your mom? If it's just mom, it could be a medical issue with HER vs. a problem with the water in your home.

~Perhaps it’s not your water. When you are dehydrated you concentrate the salts with your saliva when you will taste salt in your mouth and on your lips! 

~If mom has had Covid, this could be the after effects of the virus causing taste changes which are sometimes long lasting and other times short lived.

Geaton has some good suggestions for giving mom 'juicier' foods to increase her water intake.

Good luck.

Does she love coffee or tea? Because I hate plain water, but do well with a few spoonsful of coffee in it. I have never heard of anyone experiencing water as salty, so maybe run that past the doc next you see him or her. I looked up this odd thing, and it turns out that some people are very sensitive to water softners, and water treated with that can taste salty. So my question is, does ALL water taste salty to her? They say that there can be a backwash from some treatment methods. Worth checking out and eliminating as a cause.

If you are giving her tap water as Alva said this could be the problem. Have you tried her on bottled water? After drinking it, I cab't drink tap. You can get a generic brand for like 10 or 15 cents a bottle. And as Geaton says, there are other ways to get water into her. Me, I have to literally force myself to drink water. A bottle needs to next to me for me to remember to drink. And I don't drink 64 oz a day of anything. I don't get thirsty. I have to remind myself I need to drink.

Hello 😊 I deal with that with my mom. We joke that she's like a camel because the woman has NEVER enjoyed drinking ANYTHING.... Which is problematic at 80yrs old. So, I get super hydration drinks, coconut water, pickle juice, beet juice, flavor packets (sports which refuels electrolytes) plus foods such as leafy salad, watermelon, grapes, broths (rather than put it in a mug to drink, give it to her in a bowl, with a spoon. Good luck 😃

I give mom as much watermelon as she wants when in season.

Mom is 86 and the doc recommended 32 oz of water. He said too much was not good either. She gets the rest of her fluids from foods. So mom only drinks Propel Water (electrolyte type vs vitamin type). She loves it. We tried herbal hot tea because she is always cold and she drank that faithfully, but in a MC facility getting hot tea is not easy. So, the Propel waters are the way to go for us. I have 2 bottles sitting around with straws in them. Sometimes she picks it up but when the staff check on her, they hand her the water and she drinks. When my private care person comes in, she does the same and I do that as well. Mom is pretty stubborn but she likes sweet and Propel has a sweet taste. I drink it too but I dilute it with water. Just handing her the bottle with the straw as I talk to her works most of the time. I sometimes point to a spot on the bottle and say, drink to this line. (That gives her a goal) ;)

Would slices of cucumber or oranges take away that taste, I wonder?

My mom says that too. I do 3/4 water and 1/4 cranberry juice OR pineapple juice. I alternate the juice so my mom doesn’t get tired with one. I also feed my mom oatmeal (water and milk), her lunch is purée and I add water. May it be lasagna, I add water to it. At night I give my mom fruit shake with protein powder). I hope this helps.