Going from $50 to $115 in a few months with no explanation - while families with four people pay less than you do alone - something’s wrong with this picture. That’s not a rate increase. That’s either a billing error or a system that’s broken.
You’ve been there 23 years. You know what’s normal for this building. So start documenting: write down that you’ve been charged $50, then $55, then $61, then $115. Ask your neighbors (casually is fine) what they’re paying. Get it in writing if you can.
Then ask the landlord, in writing, to explain how your charge is calculated and to show you the actual water bills for the building. You have a right to understand what you’re paying for. “Just started charging” after two decades of renting there deserves an explanation.
If you don’t get a straight answer, there are people who can help. Many California cities have Rent Stabilization offices that handle exactly this kind of dispute. Legal Aid societies often give free consultations to seniors. Your local Area Agency on Aging can point you toward tenant assistance programs too. You shouldn’t have to navigate this alone on a fixed income.