Per person per day, 55 gals is a 15 min shower at 1.8 gal/min (27 gals) 5 toilet flushes at 1.8 gal/ flush (9 gals) and 19 gals more per person to drink, wash clothes, wash dishes and cook with.
For 2 people, the average drinking and cooking water usage is around 2 gal per day, dishwasher run is 6 gals every other day and a load of wash is around 25 gals every 3 days. That’s about 12 gals per day per person.
That leaves another 7 gals per day per person as extra.
Like I said, not onerous.
Add in a high efficiency washing machine and the extra per day per person for a family of two jumps to 17 gals.