Water. It makes up 70% of our body, we'll die in three days without it, it's the most important resource for life. I have a lot of rants about how we waste water maintaining lawns we don't use, defecate in our drinking water, and return used water back to the water table in worse condition than when we got it, but no matter how we treat it, we still have to drink it, so why not drink your water out of an earth-friendly container?
It may seem like tap water is just tap water, and a container is just a container, but that isn't always the case. For the United States, tap water is an incredibly cheap source of potable water. Water varies in mineral content and taste from area to area, so your tap water could be sweet and wonderful, or it could have a weird taste that drives you to buy bottled water, no matter what though, it is drinkable. So even if your water tastes icky, I encourage you to drink that rather than bottled water for the savings alone. I used to drink exclusively bottled water because I despised what came out of my faucet, but I had to stop once my work hours were cut back and money became tighter.
The first week of drinking tap water was hell. It tasted awful, so I didn't drink as much, so I became dehydrated and cranky. After about ten days though, I realized I didn't mind the taste of my water, and after about a month it started to taste good. Now, after four years of drinking exclusively tap water, I've started to notice the difference in water taste between cities, but unless the water truly does taste foul it just seems like the minor variation in fruit from separate orchards, and so I can drink tap water everywhere I go.
If you can stand the ten days of transition, I highly recommend it (I took the opportunity to show tap water that I wasn't its bitch), but if you don't want to, that's fine, there are other options. The first is to get a water filter. There are kinds that attach directly to the sink and others that come in the form of a refillable pitcher, but whatever you get try to make sure that the replaceable parts are recyclable. If you're less worried about the gunk in your water and more about the taste, you can also try flavoring it with tea leaves, honey, or a little juice. And if, like me, you've recently become aware of water chlorination and the nasty things it can do to your body, then keep a pitcher of water out overnight to let the chlorine evaporate and use the water the next morning. It's not a perfect solution, but it works.
Despite the possible drawbacks, I still think I'm incredibly lucky to live in a place that commonly has indoor plumbing with drinkable water. I could drink bottled water, soda, or "healthy" drinks, but why have any of those except as a treat when I can have more water than I can drink for pennies? People also ask why I bother to carry around a water bottle when I can get free water cups anywhere. Well, that's the other thing about zero waste; I don't just carry a water bottle because I'm okay with tap water, I carry a water bottle because I don't want to go through hundreds of single use cups and bottles in a year.
When I carry a water bottle I never need to get a drink at food stands or fast food stops, I'm never left thirsty with nothing to drink, and and I never have to stop at a vending machine or quickie mart for something to drink before work. With a water bottle, I always have a drink I like nearby and never have to accept a disposable bottle or cup for any reason. A lot of the time when people hold out a drink cup to me all I have to do is hold up my water bottle and smile and they immediately understand. No explaining, no arguing, no derision. My water bottle is a universally understood symbol of zero waste sustainability. Needless to say I love it and never go anywhere without it.
As much as I love what my water bottle does for me, as soon as this one wears out I have my eye on the new Klean Kanteen Reflect, which uses no paint or plastic in its design and is constructed from reusable and recyclable materials. My current water bottle works just fine, though I've been waiting for an accident to happen so that I can get one that isn't leaking chemicals into my water. However in my desire to not create more matter to be downcycled or landfilled, I've decided to put off getting my dream water bottle until the last possible second. If you are just starting out with a water bottle though, or can find a way to recycle the one you already have (mine has no numbers on it, that probably means it's extra-toxic. sigh), I totally recommend that you get a stainless steel water bottle with no liner. No liner means nothing on the inside to dent, scratch, or stain, and food-grade stainless steel won't leach toxins or chemicals into your water. You can even put non-water drinks into an unlined stainless steel container and not worry about corroding or degrading the container, or the container leaching stuff into the juice (or what-have-you) on account of the acids, sugar, or other stuff in your drink. Stainless steel isn't the only way to go, but from all the research I've done I think it's the best.
So now that you've heard more than you ever wanted to on the wonders of tap water and unlined stainless steel bottles, go out and get a reusable water bottle--whatever kind you want--and refuse to accept another disposable cup or bottle ever again.
First time reading about a hundred steps to zero waste? Go here for the introduction and index.