Water:
I never had used the sink except for Storing towels and magazines, but then I found a use for it and a need and I now use it all the time. I upgraded the faucet and splash boards, didn't have it on my year, and replaced the pump motor with a quiet one. now works great.
I still use my "Water System" in that I got 3 5-Gal big water bottles, the blue-green ones you usually see on water coolers in offices etc... with the hand pump. Lower right corner of pic (they have a battery one, but trying to keep thing simple without breaking and batteries) I then fill them when I go to the market, they have those refill stations for a $1.75 @ 5 Gal.
I use them for cooking/drinking and the sink water for anything else. This guarantees the taste won't be camp/chlorine tasting and better than home water. It's cheap, easy to refill.
I use about 3/4 or a little more on 3-4 day trips. IF I go longer, I'll carry two. One to use while I refill the empty one.
I have 3 just so I can take two and still have a back-up at home.
I also get that green Moss in the Brita at home.. heheh Slime water algae but if you've done any camping, you're used to it...
I'll fill up the TD water with a camp hose or hose at home. It's clean, drinkable in a bind but used for Misc stuff, brushing teeth, rinsing etc...
Typically, when I get back I'll have some water in the bottle left, I'll let it stay if it's some and they use the residual from the next bottle to fill it. or some thing like that. Or, I just pour it out and refill full.
For my little quick "Sleep & Go"s trying to get somewhere, I got a little 2-gal version that fits in the sink so I don't have to mess with the bigger 5-gal ones for just quick night and go...
So far, so good...