What is a good source? What else can I use or do?

I've always heard that lemonade is good to use when you're prone to kidney stones. If sugar is a problem, you can make yummy lemonade with Splenda. (That's what Chick Fil A uses for their sugar free lemonade, but it costs $11 a gallon around here.)

I read an article once about putting a little jello powder in water to get your toddler to drink more of it when dehydrated (after a stomach virus). There's a little salt in jello, btw.

You can put sliced oranges and lemons (or strawberries or cucumbers) in water to allow them to steep and make "fruit infused" water. It's pretty tasty.

Of course, none of this will help if she just *won't* drink. I like the idea of making it a game -- "Help me drink all of this water."

Most elders loose their drive to drink when they need to, and they do not easily recognize when they get dehydrated. Most elders also enter the hospital with blood work that reads dehydration. For the continuous problem with UTIs consider the supplemental capsules in D-Mannose, about 30.00 for 120 capsules and I order my Source Natural from Amazon. They are large capsules and too large for many elders, but the powder is tasteless and can be dumped in a spoon of pudding or small amount of water. Stops bacteria from adhereing to the bladder wall much as cranberry does, but without the need of fluids in large amounts and without the acidity. Worth a try, works for me, and I am actually against almost all supplements and vitamins. Your Mom may like things like jellos and etc a lot more than just water. I almost mix a bit of apple juice in mine as I don't like water, but a spoon of apple juice or coffee can get me to drink it. Wishing you good luck. You can but try.

Pippy this may sound like a long shot but it’s amazing how it’s worked for my DH aunt, 94, with dementia.
I buy the little small bottles of water. I loosen the lid and leave them by her chair. She will empty several of those throughout the day. I told her when we first started with the small bottles that the doctor wanted me to drink several of them everyday and I needed her to help me. I would drink mine down and she would drink hers to help me. She thought it was funny.
If the water is in a glass, she ignores it.
I offer it to her with her meds. She takes three diff groups of meds. She drinks at least half a bottle with each group.
She also drinks two cups of decaf each morning. It’s sweet so she likes it. She’s a big fruit lover. Like Barb said, melons and citrus are full of juice. She drinks a milk shake daily which is really a protein drink we add ice cream to and different fruits. She won’t eat soup. I think it’s too tedious for her. Popsicles are good.
My mom tasked herself with drinking her water each day by lining up several glasses on her kitchen counter. She would pass them going back and forth to the bathroom or when she would exercise walking around the house. She found it easier for her to use a straw. Her finger tips were numb so she couldn’t hold the glass. She would just leave the glass on the counter and use her straw. She had CHF and when it was bad and she had to limit her water, I was told to count any water I added to her food to come to the total allowance for the day, so just realize that whether it’s juice or jello it counts.
I think aunt started drinking more water when she quit worrying about having to get to the bathroom. And I think she’s a bit OCD about it now. She sees a half full bottle and she wants to finish it off. If your mom doesn’t like water then give her whatever she will drink. Also notice if her mouth is dry or moist, the color of her urine etc. She may have difficult veins that roll and actually not be as dehydrated as you suspect.
Here is a link you might find helpful.

https://www.femina.in/wellness/all-you-need-to-know-about-dehydration-165136.html#preventive-tips-for-dehydration

There is a lot of water in watermelon and other juicy fruits. Also, soup can be a good source of hydration.