How can I reduce excessive water bill costs?

The first thing I'd do is check your meter carefully and look for any leaks around the house. I once had a crazy high water bill and it turned out to be a tiny leak under the kitchen sink that I didn't even notice - just a drip here and there, but it was doing serious damage to the bill. If you notice weird usage, call your water company to come check it out, so at least you can rule out the problem right away. In the meantime, install flow reducers on your faucets and shower: they cost next to nothing, and they really do help without you having to give up anything practical.

For the rest, change a few small habits. Turn off the water while you're brushing your teeth or washing dishes, fix any faucet that's leaking even slowly (it seems like nothing but multiplied over months and months it makes a real difference), and if you ever need to replace your washing machine, pick one with a good efficiency rating. If you share the house with other people, talk about it together - often the problem is that nobody knows how much the other person is using, and it just takes a conversation to make everyone more aware.

One last thing: ask your water company if they have discounted rates based on income or if they offer discounts for lower usage. I think a lot of people don't know that these things exist. And if your bill still seems weird compared to other quarters, write to them with the details - sometimes it's just a meter reading error.