Mom wears Depends, but as she stands up from using toilet she has loss of urine and wets on the outer cover of new Depends. Any suggestions?

i think u should have her sit a little longer to make sure all is out. contact doc to make sure she doesn't have any gyn issues. u know with age our womb drops. seeing a doc is important. also, with kindness and speaking with her gently that will work. sometimes its our diet and or maybe she should stop drinking at late hours. may sure she's drinking her 8 glasses as early part of the day. rather than after 6 or 8pm. just make sure she has a glass to sip some like a sipping cup or something just in case her throat gets dry.

I've been noticing this on myself, also. I found that the urine does not completely empty when sitting, but when I sort of stand and lean forward, it will gush out more, just like a man standing to pee. It took a while of wetting my new underwear until I realized I needed to take time to pee and then when the peeing into the toilet while sitting was done, I needed to partially stand and lean forward to get out the rest of the pee. There is also medicine a urologist can prescribe to help her completely empty her bladder.

A change of position often leads to being able to empty the bladder more.
If mom is sitting in a chair, recliner or in bed before you get her up to go to the bathroom change her position and wait a little bit before getting her up. If she is in a recliner recline it a bit more or sit it up more fully and wait a minute or so. If she is in bed have her sit on the side of the bed for a minute, if she is sitting in a chair upright let her stand a bit and move before getting her on the toilet.
Many of these will help with her balance before she gest moving anyway.
Once on the toilet let her take a bit of extra time before getting up. You might even want to get ready with a washcloth or absorbent pad (cut up a few pads and use those) and place it so that it will absorb any leakage as she stands. This should prevent the pull up from getting soiled right away.

You could press gently on the area of her bladder before she gets up and she will feel the urge again

I wondered why aides would leave my MIL for a few minutes when she was in the bathroom its because when we are older our bladders tend to slip down making it hard to void completely. With your Mom Dementia, she has forgotten she needs to push to void her bladder completely. My Mom didn't even know what I meant when I said to push. If you let her sit a little longer, she may (or may not) get the urge to push again. And like Midkid said, having her lean forward may help.

Encourage her to sit on the toilet for a few more minutes. Bending slightly from the waist, if she's capable, will help push that little extra bit of urine out.

There's no rush--don't make her hurry, becauase that will end in her having accidents, which as you've discovered, cause more time wasting than just being a little more patient.