We use just under 5 gallons of fresh water per day for 2 people. This is in relatively cold average temperatures, with infrequent swimming and doesn't count: laundry, hosing down the boat and foul weather gear which we do when we take on water. It does include showering - we rarely use marina facilities...just because we rarely are at a marina and when we do dock long-term we don't choose to pay every day to shower on land.
From what I can tell, on average a US household uses about 65 gallons per day (1 2) although that number varies widely. You can use this worksheet to roughly estimate your household's usage. Leaks not included of course. We carry 66 gallons in our normal tankage and it lasts us approximately 2 weeks.
We do not use salt water regularly for washing dishes or bathing. We will rinse large pots or very messy pots with salt water in the cockpit occasionally and we will shampoo if we are already swimming before a fresh water rinse.
We use pressure water for everything. We don't even have a foot pump yet although we plan to install one this winter.
How much water do you use? I'm wondering if our usage will go up when we get to warmer weather and if so by how much.