Does she eat wet food?  If so, she probably doesn't need additional
water.

If your cat appears to be dehydrated, you must get her to the vet right
away.  She may even need an emergency IV!!!  Your pet might have a physical
problem which makes her not feel like drinking.

However, if like you say she WILL drink if you hold the container try these
ideas.

Cats don't drink a lot of water in there natural state (wild), a great deal
of moisture comes from their prey.  So a lot of their fluid intake needs can
be met with canned food.  But you're right, they still need to drink some!
My cats like food with lots of gravy (fluid in it), they always slurp up all
the gravy  leaving only a little dry canned food behind. But a cat  rarely
needs to drink as much as a dog.

Cats are very finicky about how fresh the water is.  Do wash and refill her
water bowl daily?
Maybe for her you need to change the water twice a day.  Be sure to wash the
bowl everyday too, to prevent even the slightest algae buildup which can
effect the taste.  Also, don't use a plastic water dish - use metal or
ceramic instead - the plastic can make the water taste funny.
Some cat owners even give their cats bottled water, saying they prefer the
taste.

Some cats prefer RUNNING water, this is where 'cat fountains' come in handy.
(Look for them at your pet store.) Try one with a filtration system so the
water always tastes fresh.  The water fountains are great if you have to
leave the cats on their own for a night or two - they have a large reservoir
so the water won't run out and the filter keeps it fresh.  Also practically
untippable, you don't have to worry about the cats knocking the water dish
over and spilling out all the water.

I had one cat that loved to drink from the sink faucet, practically the
only water she would drink.  She'd follow you into the bathroom and insist
on a drink.  It was very cute! Now I have a cat who wants to drink from the
toilet.  That's not so cute...

-- maryjane

Try a pet drinking fountain, she may find it fascinating.

Since you mentioned later on that she is consuming canned food, this
really isn't a dire situation since most of her moisture needs are being
satisfied with the food. In the meantime you could add some water to the
canned food and mix it up, but not so much that it makes a soup.