I've already dealt with the toilet here. Switching to a 'composting' toilet has allowed me to remove a lot of pipes, valves, through hull fittings and a large storage tank. It's working well. Sawdust, pine needles or dry sea grass, as found along the high tide line of many beaches, all serve well as substrates. There's some satisfaction to be had by managing to simplify things without loss of function.
On the intake side, loading water has sometimes been awkward due to the unreliability of my engines - making maneuvering in close quarters hazardous. My preference to anchor for free in a river or bay as opposed to paying for a marina berth also limits my options. There aren't many anchorages with a fresh water tap available.
Many people have water makers these days. Salt water to fresh sounds ideal - there's no shortage of salt water out here. However, water makers are expensive, require a lot of power to run, need operating regularly or their workings become gummed up, and can only be used where the salt water is clean - which isn't the case at every anchorage (not everyone uses a composting toilet or holding tanks).
So, I have been relying on my rain-water cating system, which I described installing here.
Of course, crossing the Atlantic, I couldn't rely on rain water. It might well have been dry all the way across. As it happened it probably rained every day after the first week, and often in such quantities I could have refilled my tanks many times over. I simply had to carry enough water to get me across, plus a contingency. (I actually carried far too much for too long - mistake!). But even here, having a supply of rain water available to supplement my basic supply would have allowed me to have plenty of showers and do all the laundry I wanted - if I hadn't been preoccupied with more pressing needs at the time.
Since arriving in the Caribbean a month ago, I haven't needed to find a tap anywhere, and my tanks are currently half full. It rains often enough to supply all we need. And we swim every day, and shower afterwards. We're pretty good at using small quantities for washing up, and use a pressure cooker a lot - which needs very little water.
I'm set up so that I can fill containers from a tap - one in each hull - when it rains. A decent downpour can give me 100 litres - I have 4 x 25l containers, and so far haven't felt the need to go out in the rain to empty the containers into the tank for a refill. I have considered plumbing the taps directly into the tanks, via a filter. It's still quite a bit of work lugging the containers onto the deck to fill the tanks. However, I've sometimes forgotten to turn off the collecting taps when I've gone sailing, and a bit of sea spray is enough to contaminate a tank of water so that you wouldn't want to drink it. So there is some benefit of manually emptying the containers. I get the chance to taste the water if I have any suspicions of contamination. And containers of water are handier for doing the laundry, which we do in a great big bucket on deck.
Seabirds don't seem to be in the habit of sitting on boats around here, which eliminates a major source of contamination. However, my decks aren't perfectly clean, and rain picks up dirt in the air, so I add a little thin bleach to each tank - diy chlorination.