I live in DC, it is ridiculously expensive but rent increases are capped, google says the formula is CPI + 2% but no more than 10%/yr. If she stayed in the same

I live in DC, it is ridiculously expensive but rent increases are capped, google says the formula is CPI + 2% but no more than 10%/yr. If she stayed in the same unit she might want to make sure her landlord isn't raising her rent illegally.